Ice Core Science

Home , Ice cutting, Ice drilling, Kohnen Station, Nicholas Shackleton

PAGES International Project Ofﬁ ce Sulgeneckstrasse 38 3007 Bern Switzerland Tel: +41 31 312 31 33 Fax: +41 31 312 31 68 [email protected] Text Editing: Leah Christen News Layout: Christoph Kull Hubertus Fischer, Christoph Kull and Circulation: 4000 Thorsten Kiefer, Editors

VOL.14, N°1 – APRIL 2006 Ice Core Science

Ice cores provide unique high-resolution records of past climate and atmospheric composition. Naturally, the study area of ice core science is biased towards the polar regions but ice cores can also be retrieved from high .pages-igbp.org altitude glaciers. On the satellite picture are those ice cores covered in this issue of PAGES News (Modiﬁ ed image of “The Blue Marble” (http://earthobservatory.nasa.gov) provided by kk+w - digital cartography, Kiel, Germany; Photos by PNRA/EPICA, H. Oerter, V. Lipenkov, J. Freitag, Y. Fujii, P. Ginot) www Contents

2 Announcements - Editorial: The future of ice core research - Dating of ice cores - Inside PAGES - Coastal ice cores - Antarctica - New on the bookshelf - WAIS Divide ice core - Antarctica - Tales from the ﬁ eld - ITASE project - Antarctica - In memory of Nick Shackleton - New Dome Fuji ice core - Antarctica - Vostok ice drilling project - Antarctica 6 Program News - EPICA ice cores - Antarctica - The IPICS Initiative - 425-year precipitation history from Italy - New sea-ﬂ oor drilling equipment - Sea-level changes: Black and Caspian Seas - Relaunch of the PAGES Databoard - Quaternary climate change in Arabia

12 National Page 40 Workshop Reports - Chile - 2nd Southern Deserts Conference - Chile - Climate change and tree rings - Russia 13 Science Highlights - Global climate during MIS 11 - Greece - NGT and PARCA ice cores - Greenland - NorthGRIP ice core - Greenland 44 Last Page - Reconstructions from Alpine ice cores - Calendar - Tropical ice cores from the Andes - PAGES Guest Scientist Program

ISSN 1563–0803 The PAGES International Project Ofﬁ ce and its publications are supported by the Swiss and US National Science Foundations and NOAA. 2 Announcements: Ice Core Science

Editorial: Past, present and future ice core research Ice core science is still a young fi eld of paleoclimatic and atmospheric research. Essentially, it all began in the 1960s when American, Danish and Swiss researchers retrieved the fi rst deep ice core record from Camp Century, northwestern Greenland. From that point on, it has been a success story, with many national and international deep ice core projects changing our view of the Earth’s climate system. The documentation of unprecedented rapid climate variations in Greenland ice cores during the last glacial (Dansgaard-Oeschger events, named after two pioneers in ice core research), and the quantitative reconstruction of greenhouse gas concentrations from air bubbles enclosed in the ice, are just two of the most striking examples of how ice core science has advanced our knowledge. The success of ice cores alongside other outstanding paleoclimatic archives, such as marine and lake sediments, tree rings, corals, etc., stems from their high temporal resolution combined with their coverage of many glacial cycles. In addition, the combination of various climatological and atmospheric data streams (temperature, gases, aerosols, etc.) from the same independently dated archive make ice cores extremely valuable. Despite its rather short history, ice core science has gained huge momentum and had a very strong impact on paleoclimatology. It 500 has reached full speed only within the last decade, as refl ected by the extraordinary development of the publication history of ice core related papers (see Figure), which have experienced a six-fold 400 increase in the last 15 years, and by the rapid multiplication of ice core drilling projects in different regions of the globe, bringing new 300 national players such as China, Korea and India into the game. High time to bring together the most important results gained 200 from various research groups worldwide and to think about the future. Accordingly, this issue of PAGES News ggivesives anan overviewoverview ofof the results of many of the major ongoing ice core projects, reach- 100 ing spatially from the poles to the equator and temporally from

No. of publications/year recent climate variability to paleoclimatology over the last 800,000 0 years. The need to look ahead and shape the future of ice core sci- 1984 1992 2000 2008 ence in multinational collaborations has long been recognized. In Year the last two years, this has led to the “International Partnerships in Figure: Publication history of papers with Ice Core Sciences (IPICS)”, an open planning body of currently 18 the keyword “ice core” from 1987-2005. nations that has identifi ed the most important scientifi c questions Information was retrieved from SCOPUS (www.scopus.com/scopus/home.url). to be addressed in future ice core projects. These questions have been channeled into four IPICS white papers (www.pages-igbp. org/science/initiatives/ipics/), which are also summarized in this issue of PAGES news. The timing of this newsletter is also fi tting, considering the upcoming International Polar Year (IPY). IPY will be the starting line for many of these future ice core projects, which will keep us glaciologists busy for another 10-20 years, and will provide the paleoclimate community with more detailed, quantitative and potentially paradigm-changing ice core results.

HUBERTUS FISCHER PAGES Guest Editor Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany huﬁ [email protected]

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PAGES NEWS, VOL.14, N°1, APRIL 2006 Announcements 3

contributions to PAGES during their Ababa. He has been active in PAGES time on the committee especially as the PEP III African Coordinator. Inside PAGES in building the community in their Cathy Whitlock (USA), a paleoecolo- home countries, and we gratefully gist, is Professor of Earth Sciences at acknowledge their help and dedica- Montana State University. She has Lately, the PAGES IPO has been tion. An open call for nominations important links to the modeling and buzzing with visitors. Denis-Didier for one additional SSC member will paleo-ecology communities. Rousseau (France) spent a week at close 15 September 2006. We partic- the IPO preparing a Loess-dust activ- ularly encourage nominations of pa- PAGES jobs database ity, Hubertus Fischer (Germany) was leoscientists from Russia and former PAGES free online listing of paleosci- in the offi ce to guest-edit this spe- Soviet Union countries, since this ence jobs has just been expanded to cial issue and work on the new IPICS geographic region is currently under- include a quick and simple form for website, Isabelle Larocque (Canada) represented on the SSC. For details you to add your job offer directly to is helping to establish a new PAG- on the nomination procedure, please the jobs page. Jobs are divided into ES Databoard Working Group and go to: www.pages-igbp.org/people/ categories (PhD, faculty, etc.) and meeting, Dmitry Sonechkin (Rus- sscleaders/nominations.html. will be posted the same day. Post or sia) discussed a contribution to the search for jobs at: www.pages-igbp. PAGES/CLIVAR Intersection, Olga Incoming PAGES SSC members org/services/jobs/. Solomina (Russia) will help to guest- PAGES welcomes four new mem- edit a GPC sspecialpecial issueissue onon climateclimate bers to its SSC this year. Bette Next issue of PAGES News change in mountain regions, and Otto-Bliesner (USA) is Head of the The next issue of the PAGES news- Bert Rein (Germany) will be here to Paleoclimate Group at NCAR and letter will be published in July. set up the National PAGES Germany Lead Author of the IPCC paleoclimate Please send your general contribu- website. More information about chapter. She brings knowledge and tions to the open section, as well PAGES Guest Scientist Program can experience of climate modeling to as program news, workshop re- be found at: www.pages-igbp.org/ the SSC. Indra Bir Singh (India) is ports and humorous tales from the people/guestscientists.html. Professor of Geology at the Universi- fi eld, to Christoph Kull (kull@pages. ty of Lucknow. He has a background unibe.ch) by 15 May. Guidelines Outgoing PAGES SSC members in terrestrial paleoenvironmental for contributions can be found at At the end of 2005, PAGES Scientifi c science and brings new expertise in www.pages-igbp.org/products/ Steering Committee said farewell to sedimentology to the SSC. Moham- newsletters/instructions.html. Daniel Olago (Kenya), Ashok Singhvi med Umer (Ethiopia), a palynolo- (India), and Olga Solomina (Russia). gist, is Associate Professor of Earth All three members made enormous Sciences at the University of Addis HOLIVAR 2006 Open Science Meeting: Natural Climate Variability and Global Warming

12 - 15 June 2006; Environmental Change Research Centre, University College London, UK The meeting will examine how and why the natural climate system varies and assess the relative importance of natural processes and human activity in explaining global warming.

Meeting Themes: The HOLIVAR2006 Open Science Meeting will consist of 12 keynote talks, a panel discussion and 4 poster sessions organised into the following 4 themes:

- Theme 1 Millennial Time Scales (Chair: Bernd Zolitschka) - Theme 2 Decadal to Centennial Time Scales (Chair: Jonathan Holmes) - Theme 3 Climate Variability in the Last 2000 Years (Chair: Heinz Wanner) - Theme 4 Rapid Hydrological Change (Chair: Ingemar Renberg)

Registration Deadline: 1 May 2006 Further Information: www.holivar2006.org

PAGES NEWS, VOL.14, N°1, APRIL 2006 4 Announcements

New on the PAGES bookshelf

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Tales from the ﬁ eld

PAGES on ice: Fernando Valero-Delgado from the Alfred-Wegener-Institute for Polar and Marine Research is not only the ﬁ rst Ecuadorian to reach the North Pole but most likely also the one who has advanced furthest into the Antarctic. Here he takes a break from the EPICA ice core drilling in Dronning Maud Land, Antarctica, (0°W, 75°S) with some relaxing literature.

Photo: Johannes Freitag, AWI, Bremerhaven, Germany

PAGES NEWS, VOL.14, N°1, APRIL 2006 Obituary 5

Nick Shackleton One of the most eminent geoscientists of all times Professor Sir Nicholas Shackleton, “Nick”, passed away on 24 January 2006, at the age of 69.

Since the late 1960s, when Nick had started to develop the techniques required for high-resolution isotope stratigraphy, he was at the forefront of research in paleoclimate and remained one of the most infl uential and brilliant scientists in this fi eld. These techniques were fundamental in allowing us to obtain the fi rst isotope records showing the history of ice-sheet fl uctuations during the Qua- ternary. The reconstructed glacial-interglacial cycles were not only more numerous than previously supposed but also matched the long-term variations of the astronomical parameters. The paper he co-authored with Jim Hays and John Imbrie in Science inin 1976, now a classic citation and one of the most important Quaternary research papers ever, showed that the variations in the Earth’s orbit and axis of rotation are the pacemakers of the major climatic changes during the Quaternary. This paper, for the fi rst time, validated the “Milankovitch” Nick Shackleton at the meeting on “Climate and Ozone at the Dawn of the Third Millennium” organized by Drs A. Ghazi and A. Berger in Brussels, 13-14 May 1996 in honor of Paul Crutzen hypothesis. (Nobel Prize 1995), B. Bolin (Blue Planet Prize 1995), W. Dansgaard and N. Shackleton (Crafoord Nick devoted most of his life to Prize 1995). Photo by André Berger. the investigation of the relationship fying Cenozoic stratigraphy. His role Stockholm and Padova Universities. between orbital forcing and climatic in INQUA, where he was President He was invited to deliver many pres- changes. He was particularly infl uen- from 1999 to 2003, was particularly tigious lectures and was awarded a tial in the development of high-resolu- infl uential, leading to the Union be- knighthood by Queen Elizabeth II for tion astronomically tuned timescales coming a full member of the Inter- “services in the Earth Sciences” in for geological records, the re-evalu- national Council of Scientifi c Unions 1998.Nick was not only a renowned ation of the Bruhnes-Matuyama in 2005. Furthermore, he was one of scientist but also a brilliant clarinetist. geomagnetic polarity reversal and the pioneers who launched the IM- His collection of clarinets is unique in the investigation of high-frequency AGES program within PAGES in the the world (even more so than his sci- climate changes during the last gla- mid 1990s, served as a member on entifi c work, he told me once!) One cial cycle. More recently, the success the IMAGES SSC, and demonstrat- of his great pleasures was perform- of the Quaternary isotope sequences ed in numerous papers how a new ing in dedication to his friends each convinced him to extend his research generation of high-resolution pa- time he had the opportunity. into the Neogene (and even the Pa- leoceanographic sediment records Professor Sir Nicholas Shackleton leogene). His effort contributed to the from well-chosen high-rate deposi- was definitely one of the greatest determination of an unprecedented tion sites can uncover mechanisms geoscientists of all times, but most continuous high-resolution times- of rapid climate changes. of us are also losing Nick, a good cale for the last fi fteen million years. In view of such accomplishments, friend. One of his last major contributions, it is not surprising that Nick received published in Science in 2000, clarifi es the most prestigious awards allocat- ANDRÉ BERGER a long-standing puzzle of the phase- ed to geosciences: the Blue Planet Honorary President European Geosciences Union relationship between astronomical Prize of the Asahi Glass Foundation forcing, ice sheets, carbon dioxide (2005) and the Crafoord Prize of the Institut d’Astronomie et de Géophysique concentration and ocean tempera- Royal Swedish Academy of Sciences Université Catholique de Louvain ture.Throughout his career, Nick ad- (1995). He was Fellow of the Royal Louvain-la-Neuve, Belgium vised a large number of scientists at Society, Foreign Associate of the US [email protected] all levels and participated in numer- National Academy of Sciences, and ous commissions in charge of clari- an Honorary Doctor of Dalhousie,

PAGES NEWS, VOL.14, N°1, APRIL 2006 6 ProgramProgram ProgramNews: News: Ice News Core IPICS Science

The future of ice coring: International Partnerships in Ice Core Sciences (IPICS)

EDWARD J. BROOK1, ERIC WOLFF2, DORTHE DAHL-JENSEN3, HUBERTUS FISCHER4, ERIC J. STEIG5, ON BEHALF OF THE IPICS STEERING COMMITTEE 1Dept. of Geosciences, Oregon State University, Corvallis, USA; [email protected] 2British Antarctic Survey, Cambridge, UK; [email protected] 3Niels Bohr Institute, University of Copenhagen, Denmark, [email protected] 4Alfred Wegener Institute, Bremerhaven, Germany; huﬁ [email protected] 5Dept. of Earth and Space Sciences, University of Washington, Seattle, USA; [email protected]

Introduction: Goals of IPICS A ﬁ fth, and critical, element of IPICS past. However, we know that just Ice cores provide information about is the development of advanced ice before this time, the characteristic past climate and environmental con- core drilling technology. frequency of climate variability was ditions on timescales from decades different, with cycles of 40,000 years to hundreds of millennia, and direct The oldest ice core (Fig. 1). The origin of this shift is a records of the composition of the - A 1.5 million year record of climate major puzzle. Studying the interac- atmosphere. As such, they are cor- and greenhouse gases from Antarc- tions of climate and biogeochemis- nerstones of global change research. tica try during and before the transition For example, ice cores play a central We currently live in the latest warm will allow us to: role in showing how closely climate phase in a series of cold/warm os- • Understand the natural variabil- and greenhouse gas concentrations cillations occurring every 100,000 ity that has led to our current were linked in the past, and in dem- years. Ice core records show that climate. onstrating that very abrupt climate for the last 650,000 years, carbon • Test the hypothesis that the switches can occur. With the comple- dioxide and other greenhouse gas- change from 40,000 to 100,000 tion of major projects in Greenland es have been closely linked to these year cycles was caused by a and Antarctica over the last 15 years, climate cycles (Fig. 1). However, we lowering of atmospheric carbon the international ice coring commu- still lack understanding of the nat- dioxide concentrations. nity is planning for the next several ural regulation of carbon dioxide, • Better understand the times- decades. The costs and scope of fu- and the ampliﬁ cations that make cales and processes that control ture work create the need for coor- the climate system so sensitive. exchange of carbon dioxide (in-

dinated international collaboration. Both of these factors are important cluding excess CO2 from human Developing this international col- as we try to predict the future. activities) between reservoirs, laboration is the charge of IPICS, In- Furthermore, our oldest ice core, and the links between climate ternational Partnerships in Ice Core from the European Project for Ice and the natural cycles of gases Sciences, a planning group currently Coring in Antarctica (EPICA), ex- such as methane, and of terres- composed of ice coring scientists, tends back 800,000 years into the trial and marine aerosols. engineers, and drillers from 18 nations. 3. 0

] 18 δ O stack Two international meetings in °° / ° [

2004 and 2005 (Brook and Wolff, 2006) lead to an ambitious four-ele- 4. 0 bent hic

ment framework that both extends O

18 -350 the ice core record in time and en- δ hances spatial resolution. The four 5. 0 -380 EPICA Dome C ]

projects were deﬁ ned as: °° 1) A deep ice coring program in -410

Antarctica that extends through δ D [°/ the mid-Pleistocene transition, 320 -440 Vostok

a time period where Earth’s cli- ] 280 EPICA Dome C -470 mate shifted from 40,000 year to 100,000 year cycles. 240 [ppmv 2) A deep ice core in Greenland re- 2

covering an intact record of the CO 200 last interglacial period. 160 3) A bipolar network of ice core re- 0 250 500 750 1000 12 50 1500 cords spanning approximately age [kyr before present] the last 40,000 years. 4) A global network of ice core Fig. 1: Top: benthic oxygen isotope stack from Lisiecki and Raymo (2005) showing the shift from 40 ka to 100 ka global climate cycles in the mid-Pleistocene. Middle: EPICA Dome C stable records spanning the last 2,000 isotope record showing the evolution of central east Antarctic climate for the last 800,000

years. years (EPICA community members, 2004). Bottom: CO2 record from the VostokVostok (Petit(Petit et al., 1999) and Dome C ice cores (Siegenthaler et al., 2005).

PAGESPAGES NEWSEWS, VOLOL.14,.14, NN°1,°1, APRILPRIL 22006006 ProgramProgram ProgramNews: News: Ice News Core IPICS Science 7

Fig. 2: Left: Surface elevation (m) of the northern section of the Greenland ice sheet (Bamber et al., 2001) and radar echo sounding section from NEEM 1 to NEEM 2 (http://tornado.rsl.ku.edu/Greenlanddata.htm). NEEM 1 is the likely location of the new core in NW Greenland. To accomplish these objectives, we The last interglacial and beyond IPICS plans to obtain a reliable high- need to obtain a reliable ice core - A northwest Greenland deep ice core resolution Greenland ice core record record of climate and biogeochem- drilling project of the onset of the Eemian period and istry extending through several of Greenland ice cores provide a com- possibly the previous glacial period— the 40,000 year cycles and up to the pelling picture of the abrupt, mil- a record of at least 140,000 years. present. This requires that we pro- lennial-scale, climatic flips of the The fi rst step is to identify a suitable duce a replicated record extending last glacial period (Dansgaard- site, where the full Eemian period is at least 1.2 million and, preferably, Oeschger events). Understanding the present and not disturbed by fl ow. 1.5 million years into the past. cause of these events, and their impli- Based on radio echo sounding pro- Undoubtedly, ice older than cations for future change, is one of the fi les produced by the University of 800,000 years does exist in the Ant- hottest topics in climate studies, with Kansas, the team at the University arctic ice sheet. The fi rst task will signifi cant policy implications. How- of Copenhagen has deduced that the be to carry out an iterative process ever, the existing Greenland cores are most likely candidate area is in north- of modeling and survey to identify defi cient in one important respect. The west Greenland (Fig. 2). They traced possible sites in the relatively little- last interglacial (Eemian) has proved to internal layers dating back to 82,000 surveyed interior of East Antarctica, be a diffi cult target; even in the most years before present to a preferred where accumulation rates are low recent NorthGRIP core (NGRIP Mem- site where the ice is 2542 m thick, and and ice thickness is high. Observa- bers, 2004), the Eemian record was the Eemian section is estimated to be tion of internal radar layers, allow- incomplete due to basal melting. 80 m thick, with no signs of folding or ing us to follow layers of known The last interglacial period is criti- other problems. age from existing drill sites, will cal because it appears to have been IPY is a target for the start of the be critical. warmer than the present, allowing us deep Greenland drilling. The logisti- The drilling itself poses no to see what happens in a climate like cal, technological and scientifi c chal- unique technical challenges, apart the one we are approaching. Models lenges require an international effort from extremely cold conditions, but suggest that the Greenland ice sheet that builds on the successful North will require a signifi cant logistical will waste away under warmer condi- GRIP program, and scientists from effort. Some required survey work tions; the last interglacial provides a several nations have already ex- is already planned for the Interna- test of such models. Supplementing pressed interest in participating. tional Polar Year (IPY; 2007-2008). existing low-resolution records from IPICS will assess the results of this other archives, a new Greenland ice The IPICS 40,000 year network work in order to recommend one core would indicate the character of - A bipolar record of climate forcing or more target drilling sites. Many the Eemian in the North Atlantic re- and response recent major ice core projects gion and allow us to: Recent paleoclimate reconstructions have been multinational, and we • Chart the full course of an inter- clearly document that the Earth’s anticipate that the pooled survey, glacial from termination to incep- climate is an intricate interplay of drilling, analytical and intellectual tion at very high resolution. oceanic, atmospheric, biogeochem- capacity of all the major players • Determine if rapid climate chang- ical, and cryospheric processes. will be needed to achieve the Old- es occurred in such a warmer However, the reasons for changes est Ice project. climate or in the preceding glacial in greenhouse gas concentrations IPICS will now start drawing up period. and aerosol loads, sea-level and ice plans for how to implement the • Relate climate variations from the masses, as well as their coupling to project, with drilling starting early present and the last interglacial atmospheric and ocean circulation, in the next decade. period to the predicted scenarios are still not suffi ciently understood. under global warming. Previous ice core records from cen-

PAGESPAGES NEWSEWS, VOLOL.14,.14, NN°1,°1, APRILPRIL 22006006 8 Program News: Ice Core Science

tral Greenland and East Antarctica -32.0 deﬁ ned the overall features of gla- IS 1 IS 21 Greenland IS 8 IS 12 IS 14 IS 17 IS 19 IS 20 ]

cial and interglacial periods and -37.0 °° transitions between them, and O [°/

the characteristics of rapid climate -42.0 18 change during the last ice age, at a -30.0 δ few individual sites. However, the

] -47.0

spatial evolution of deglaciation and °° -35.0 Antarctica A7 A2 A3 A 4 A6 abrupt climate change, particularly A1 AC R A 5 O [°/

differences between northern and 18 -40.0 δ southern hemisphere patterns, and 800 the processes responsible for those -45.0 changes, cannot be diagnosed Greenland from single locations. The IPICS 600

40,000 year network of temporally [ppbv] 4 synchronized, high-resolution ice 400 800 CH cores from both polar regions will provide data needed to decipher 200 600 Antarctica climate change mechanisms. The [ppbv] focus is on the last 40,000 years 4 400 because this period includes the CH major Earth System reorganiza- tions of the last glacial-interglacial 200 10000 30000 50000 70000 90000 transition, climate variations of the age [yr before present] Holocene, and the well-dated and Fig. 3: Comparison of climate records from Antarctica and Greenland covering the last 90,000 documented sequence of abrupt years. The last 40,000 years is the best documented time period of both abrupt shifts in cli- climate changes in marine isotope mate in both hemispheres, and the large change from glacial to interglacial conditions. From stage 3 (Fig. 3). The 40,000 year net- Blunier and Brook (2001). work will: ing the glacial period, some modern the instrumental record, and too • Determine spatial patterns in en- coastal ice domes may have merged spatially heterogeneous to be vironmental parameters related with the inland ice. Ice cores from adequately characterized by the to ocean surface conditions (e.g. these locations can provide basic in- small number of existing highly sea ice and marine biological formation (snow accumulation, tem- resolved, well-dated paleoclimate productivity). perature, altitude, ice sheet extent) records. For example, temperature • Construct the sequence of on changes in the mass balance of reconstructions for the past thou- events from 40,000 years to ice caps and ice sheets. sand years remain widely debated present in different geographic A site selection team will identify because there are insufﬁ cient data areas of both polar regions at optimal new core sites and coordi- prior to about AD 1600. The spatial the highest resolution possible. nate cooperation between individual and temporal variability of past • Synchronize the new records coring projects. A science plan will precipitation, atmospheric circula- using high-resolution measure- be developed to ensure that com- tion, and sea ice extent on these

ments of CH4, CO2, and dust, as parable data sets will be available timescales remains even less well well as isotopic compositions of for all drill sites, and to coordinate known. Similarly, while greenhouse air components. efforts for process-related studies in gas concentrations are globally well • Quantify the spatial and tem- parallel to the deep ice core drilling. mixed and can be determined from poral evolution of rapid climate Two new sites have already been a small number of records, varia- changes in both polar regions. identiﬁ ed and will be completed in tions in important climate feedback • Identify climate modes and tele- the near future: WAIS Divide (see variables, such as continental dust connection patterns under differ- Severinghaus, this issue) and Talos and pollution aerosol concentra- ent climate boundary conditions Dome (see Morgan, this issue). Fur- tions, are highly regional. Improved (orbital forcing, greenhouse gas ther cores will complete the network reconstructions of all of these vari- concentration, land ice masses). over the following decade. ables are needed to answer funda- In addition, we need to understand mental questions about the natural the response of the ice sheets to cli- The IPICS 2k array variability of the climate system, mate change. Ice sheet models dif- - A network of ice core climate and and to put potential anthropogenic fer in predictions of the extent and climate forcing records for the last climate change in context. thickness of the major ice sheets at two millennia. Polar regions and high altitudes the Last Glacial Maximum, and their Climate variability on decadal to are especially poorly represented. contribution to global sea level. With century timescales is too low in Recent work under the International the expansion of the ice sheets dur- frequency to be assessed from Trans Antarctic Scientiﬁ c Expedition

PAGES NEWS, VOL.14, N°1, APRIL 2006 Program News: Ice Core Science 9

arctica, where the longest ice core �� records are expected, is a particular need, currently being addressed by �� drilling engineers. Lightweight drills �� capable of drilling to perhaps 1000

� m, and deployed without heavy logistics loads, will also be impor- �� tant. �� Implementing IPICS �� A major purpose of the IPICS2 meet- �� ing in Brussels (October 2005) was �� to establish consensus around the four IPICS projects, and to develop Fig. 4: Reconstructed continent-wide average Antarctic temperature anomalies from calibrated ice core stable isotope records. Black lines show annual data, 20-year smoothing (bold), and a steering committee and timeline 2s (annual) uncertainties. Also shown for comparison are annual average Antarctic tempera- for future work. At this meeting also tures from instrumental data (red), and 20-year smoothed instrumental records of South- representatives from PAGES (Past ern Hemisphere temperature (dashed green). After D.P. Schneider, PhD thesis, University of Washington, 2005. Global Changes) and SCAR (Scientif- ic Committee on Antarctic Research) (ITASE) program in Antarctica (see core networks, including the dozens participated and a formal relation- Mayewski, this issue) demonstrated of ice cores collected in Greenland ship between IPICS and these or- the feasibility of obtaining quantita- (see McConnell, this issue) and on ganizations is currently discussed. tive climate reconstructions on these the Arctic islands, in Antarctica, and With the consensus in hand, writing timescales, given suffi cient number from high mountains at lower lati- teams have fi nalized “white paper” and distribution of highly resolved tudes. While many of these records documents for each project, and are records (Fig. 4). are only 100-200 years in length, now moving on to developing de- However, most existing ice core they can provide guidance for the tailed science and funding plans (for records have inadequate temporal selection of new drilling locations. details of the white papers see http:// resolution, are too short to allow for At other locations, existing long re- www.pages-igbp.org/ipics). A steer- quantitative reconstructions greater cords will need to be updated being committee with representatives than one or two centuries in length, cause many provide only limited from all the nations involved has or do not overlap with modern satel- information after the 1970s (when been formed, and a third meeting lite observations. The IPICS 2k Array satellite measurements began), is planned within the next year or will provide a larger network of ice hampering calibration. two to discuss and adopt the science cores, extending high altitude and Compilation and analysis of ex- plans. Initial stages of IPICS projects high latitude proxy climate and cli- isting data will be an important part should be underway by then, and mate forcing observations to the last of the effort, including improved the scientifi c community can look two millennia. The target time frame statistical analyses and the use of forward to a richer spectrum of ice of two thousand years (2k) includes tracer-enabled general circulation core data in the future. both the industrial era and a long models. International planning and enough prior period to allow sta- logistics cooperation for core col- Project facts tistically meaningful assessment of lection and analysis will be needed. Project: International Partnership in Ice Core natural century-scale variability. This Archiving data at a single World Data Sciences (IPICS) will provide an ice core contribution site is planned. Contact: Ed Brook ([email protected]. to the global climate reconstructions edu), Eric Wolff ([email protected]) being presented to policymakers. Ice core drilling technology Participants: Scientists from Australia, Important criteria for records in the - Improvements in drilling technol- Belgium, Canada, China, Denmark, France, Germany, Italy, Japan, Korea, Netherlands, IPICS 2k Array include: ogy are needed to accomplish the New Zealand, Norway, Russia, Sweden, • The highest possible resolution, IPICS goals. Switzerland, United Kingdom, United and precise and accurate dat- Major issues include fi nding a re- States. ing. placement for commonly used drill- Funding: Support for planning from US • Spatial distribution that cap- ing fl uid components being phased NSF and European Polar Board. Support tures the dominant patterns of out for environmental reasons, de- for projects to be sought from national agencies. climate variability. veloping a system for replicate cor- Where: Global • Multiple data sets from each ing from the same ice core borehole, When: 2006 and following 1-2 decades core, to enable combination of and drilling in relatively warm ice What: Comprehensive international ice multiple records in statistically near the bed/ice interface, which has coring program on all available timescales, meaningful reconstructions. proved diffi cult in a number of re- multiparameter data sets The IPICS 2k Array will build on recent projects. A fl uid that will allow Web page: www.pages-igbp.org/science/ sults from previous and ongoing ice drilling in very cold ice in East Ant- initiatives/ipics/

PAGES NEWS, VOL.14, N°1, APRIL 2006 10 Program News

REFERENCES Lisiecki, L. E., and Raymo, M.E., 2005: A Pliocene-Pleis- Schneider, D.P., 2005: Antarctic climate of the past 200 18 Bamber, J. L., Ekholm, S. and Krabill, W.B., 2001: A new, tocene stack of 57 globally distributed benthic δ O years from an integration of instrumental, satellite, high-resolution digital elevation model of Greenland records, Paleoceanography, 20, doi:10.1029/. and ice core proxy data, Ph.D. Thesis, University of fully validated with airborne laser altimetry, Journal NGRIP Members, 2004: High resolution record of Washington, 2005. of Geophysical Research, 106(B4): 6733-6746, northern hemisphere climate extending in to the last Siegenthaler, U., Stocker, T. F., Monnin, E., Lüthi, D., 10.1029/2000JB900365. interglacial period, Nature, 431: 147-141. Schwander, J., Stauffer, B., Raynaud, D., Barnola, Blunier, T. and Brook, E.J., 2001: Timing of millennial- Petit, J. R., Jouzel, J., Raynaud, D., Barkov, N.I., Barnola, J. -M., Fischer, H., Masson-Delmotte, V. and Jouzel, scale climate change in Antarctica and Greenland J.-M., Basile, I., Bender, M., Chappellaz, J., Davis, J, 2005: Stable carbon cycle–climate relationship during the last glacial period, Science 291: 109-112. M., Delaygue, G., Masson-Delmotte, V., Kotlyakov, during the late Pleistocene, Science, 310: 1313-1317. Brook E. and Wolff, E., 2006: The future of ice core V.M., Legrand, M., Lipenkov, V.Y., Lorius, C., Pepin, science, EOS, 87 (4): 39. L., Ritz, C., Saltzman, E., and Stievenard M., 1999: EPICA-community-members, 2004: Eight glacial cycles Climate and atmospheric history of the past 420,000 from an Antarctic ice core, Nature, 429: 623-628. years from the Vostok ice core, Antarctica, Nature, 399: 429-436.

The sea-ﬂ oor drill rig “MeBo”: Robotic retrieval of marine sediment cores

TIM FREUDENTHAL AND GEROLD WEFER Research Center Ocean Margins, University of Bremen, Germany; [email protected], [email protected] Retrieval of marine sediment cores is conventionally carried out either by gravity coring or by drilling from a ship. Although a number of research vessels allow for gravity coring, the length of the retrieved cores is often shorter than desired. While this limitation can be overcome by drilling into deep-sea sediments, the availability and cost of drill-ships imposes a severe limitation on this approach. To bridge this gap in sediment-coring techniques, we developed a remotely operated underwater drill rig “MeBo” (“Meeresboden-Bohrgerät”; German for “sea-fl oor drill rig”). This portable drill can be operated from research vessels of opportunity. It is deployed on the sea fl oor and is capable of re- trieving 50-m-long cores from sediments and hard rocks. Fig. 1: Last checks on the newly developed sea-fl oor drill rig MeBo before the fi rst deep-water The drill is an electro-hydraulic test from the German research vessel METEOR. (Inset) Consolidated Pliocene marls retrieved by rotary drilling with the MeBo in 1700 m water depth off NW Africa. system that is remotely controlled from the ship (Fig. 1). A steel ar- mixture of tools specifi cally required tests, the MeBo was deployed ten mored umbilical with a diameter of for a drill job. The drill string is com- times in 25-1700 m water depth, with 32 mm is used to lower the 10-ton- posed of 3-m sections. The MeBo has a maximum drill depth of 23.65 m. heavy device to the sea bed, where the capability to drill up to 50 m into In total, about 105 m were drilled in four legs arm out in order to increase the sea fl oor, to recover cores with sand, unconsolidated and consoli- the stability of the rig. Copper wires 74-84 mm diameter, and to stabilize dated marls, as well as glacial till. and fi ber optic cables within the um- the drilled hole to a depth of 40 m. The total core length recovered was bilical supply energy from the vessel The complete MeBo system, includ- about 50 m. Especially in cohesive and allow communication between ing drill, winch, launch and recovery sediments, a recovery rate of nearly the MeBo and the control unit on system, control unit, as well as work- 100% was achieved. deck. The system utilizes commercial shop and spare drill tools, is shipped A major advantage of the MeBo rotary core barrels with diamond or within six 20’ containers. compared to drill ships is that the tungsten carbide bits, as well as push The MeBo was successfully test- drilling operations are indepen- coring barrels, and can set a casing ed on two cruises, from the research dent of any ship movements due to as needed for various lithologies. vessels METEOR (at the continental waves, wind or currents. This allows The MeBo stores drilling rods and slope off NW Africa; cruise M65-3) the recovery of non-fractured cores casing tubes, as well as push-coring and CELTIC EXPLORER (near the is- of high quality (Fig. 1, inset). and rotary barrels, on two rotating land of Rügen in the southern Baltic magazines that can be loaded with a Sea; cruise CE0511). During theses

PAGES NEWS, VOL.14, N°1, APRIL 2006 Program News 11

Relaunch of PAGES Databoard activities

ISABELLE LAROCQUE Institut National de Recherche Scientifi que, Centre Eau, Terre et Environnement Québec, Canada; [email protected] Submitting published data to data centers should be part of the ethics of paleoscience. Data centers have the mandate to collect, orga- nize and provide data to users, but they face reluctance from some scientists to submit their published data. One of the major tasks of the PAGES Databoard, launched in March 2002 (see box), is to “establish a protocol to define the expected fl ow of data from scientists”. Four years after this launch, there is still a lack of engagement from individual scientists from the paleo-community in making their data available. The PAGES SSC recently voted for more prominent actions within the PAGES Databoard. In the new structure of PAGES, data management will become a cross-cutting theme. PAGES thereby aims to reinforce the submission of data from scientists working within PAGES Foci and beyond. Figure: Maps of the data, divided by paleoarchives, available at the NOAA paleo-data center. PAGES Databoard The maps were created using free software available on the NOAA website To reach their goals, data centers The PAGES Databoard will meet in The PAGES Databoard consists of members need data from around the world, the middle of this year to discuss from all of the major data archives such which is far from the case in vari- ways to increase the fl ow of data as NOAA, PANGAEA and MEDIAS-France as well as from thematic data collection ous paleoresearch fields (see to data centers, and to promote a efforts such as the African, European and fi gure). Although many funding web portal that is user friendly and North American Pollen databases and agencies have created policies provides online access to all avail- the IMAGES program. Membership in the that couple further funding to the able data around the world using PAGES Databoard is open to all interested submission of data from previous simple keywords. A list of data scientists and organizations. projects, PAGES will adopt a strat- centers will soon be updated on Goals of the Databoard are to: egy based on science ethics. Ev- the PAGES website. In the follow- 1) establish networks for data management, ery scientist should be proactive ing months, PAGES members will 2) provide tools to facilitate data contribu- in helping to better understand be approached in various ways with tion, the climate system by submitting requests to submit their data to data 3) increase data sharing through a common his or her individual data to a da- centers. We hope that by reminding format for data and metadata inter- ta center. The more data there is scientists how important data avail- change. freely available, the easier it is to ability is, the PAGES Databoard will The success of this initiative depends on the cooperation of various database managers compare sites and proxies, and to strengthen the data-sharing ethic. but most importantly, it depends on the synthesize research results at the willingness of individual scientists to submit local, regional and global scale. If you want to be part of the their data to a participating archive. In the new PAGES structure, PAGES Databoard or you want modeling is emphasized as an in- more details on how and where Agenda tegral approach across all Foci, but to submit data, please contact First meeting and launch of the initiative: very few data centers contain mod- Isabelle Larocque at isabelle_ Kandersteg, Switzerland, 4-6 March 2002 Second meeting (planned, closed): eling data, either input datasets or [email protected]. Bern, May 2006 results from model simulations. Open meeting: end 2006, early 2007. This issue will also be targeted by the PAGES Databoard.

PAGES NEWS, VOL.14, N°1, APRIL 2006 12 National

NATIONAL CONTACT: Chile Dr. Antonio Maldonado CAEZA, Universidad de La Serena Casilla 599, La Serena, Chile [email protected] www.ceaza.cl/Members/bioloter/Integrantes/Antonio/

Chile is characterized by a wide latitudinal range (18 - 56ºS), which is reflected in a large number of different ecosystems and geographical features, such as mountains and volcanoes up to almost 6000 m asl and marine depths of 7800 m. Several types of climate are present, including one of the driest deserts worldwide and one of the more rainy extratropical places, with annual precipitation records up to 8000 mm in the southern part of Chile. There are three main climatic features that determine this gradient along Chile: the tropical circulation, which brings precipitation to the northern Altiplano plateau; the westerly belt-winds, which affect the entire southern part of Chile; and the subtropical southeastern Pacific anticyclone, which interacts with the westerly belt-wind system and determines the Mediterranean climate in subtropical Chile. Together with these three climatic features, the interaction between the cold Humboldt Stream and the presence of the Andes Cordillera, result in some of the climatic characteristics, such as the hyperaridity of the Atacama Desert. Additionally, Chile is affected by ENSO events.

National Science Highlight: Nothofagus pumilio tree-ring based reconstruction of minimum annual temperature for Chilean Southern Patagonia (51º – 55º S) from 1829 to 1996 Aravena et al., 2002 Several Nothofagus pumilio tree-ring chronologies have been developed from trees in northern Patagonia, Tierra del Fuego (Photo) in Chile and Argentina and the central Andes in Chile. These studies have demonstrated the relationship between spring-summer climate and Nothofagus pumilio tree-growth. The current climate of the west coast of southern Patagonia is dominated by a precipitation and humidity gradient. Precipitation originates mainly from the influence of the westerly winds. The reconstruction shows (Figure) that during most of the 19th century, minimum annual temperatures remained below average and increased to values fluctuating around the mean during the 1900-1960 period, followed by a clear trend with above-average values after 1963.

3 2 1 0 -1 -2 -3

emperature deviation (°C) 1820 1840 1860 1880 1900 1920 1940 1960 1980 2000 T Year Fig. Nothofagus pumilio tree-ring based reconstruction of minimum annual Photo: Nothofagus pumilio forest in Navarino Island in temperature for Chilean southern Patagonia (51º – 55ºS) from 1829 to 1996. the southern extreme of Chilean Patagonia (55ºS).

References: Aravena, J.C., Lara, A., Wolodarsky-Franke, A., Villalba, R. y Cuq, E. (2002) Tree-ring growth patterns and temperature reconstruction from Nothofagus pumilio (Fagaceae) forests at the upper tree line of southern Chilean Patagonia. Revista Chilena de Historia Natural, 75: 361-376 Villalba, R., Lara, A., Boninsegna, J.A., Masiokas, M., Delgado, S., Aravena, J.C., Roig, F.A., Schmelter, A., Wolodarsky, A. y Ripalta, A. (2003) Large-scale temperature changes across the southern Andes: 20th-century variations in the context of the past 400 years. Climatic Change 59: 177–232.

Research Institutions:

- CEAZA, Centro de Estudios Avanzados en Zonas Aridas - CMEB, Centro Milenio de Estudios Avanzados en www.ceaza.cl Ecología y Biodiversidad - FORECOS, Forest Ecosystem Services under Climatic www.cmeb.cl Fluctuations - CASEB, Center of Advanced Studies in Ecology & www.forecos.net Biodiversity - CEQUA, Centro de Estudios del Cuaternario de Fuego- www.bio.puc.cl/caseb Patagonia y Antártica www.cequa.cl Funding Agencies - COPAS, Center for Oceanic Research - Chilean Research Council www.copas.cl www.conicyt.cl - CECS, Centro de Estudios Científicos - Fundacion Andes www.cecs.cl/web www.fundandes.cl

Number of Chilean subscribers in the PAGES People Database (www.pages-igbp.org/people) on March 7th: 25 Background Photo: Cerro Tapado in northern Chile (30°S, C. Kull)

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The NGT and PARCA shallow ice core arrays in Greenland: A brief overview

JOSEPH R. MCCONNELL1 SEPP KIPFSTUHL2 AND HUBERTUS FISCHER2 1Desert Research Institute, Nevada System of Higher Education, Reno, USA; [email protected] 2Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany [email protected], huﬁ [email protected]

Introduction PARCA campaigns Ice cores provide the most direct Ice cores are the primary indicator and highest temporal resolution re- of net snowfall over the ice sheet at cord of past atmospheric and pre- all temporal scales. The PARCA ar- cipitation chemistry, and local to ray of >80 ice cores was collected regional-scale meteorology. Such re- during a series of primarily airborne cords have been used to reconstruct campaigns beginning in 1995 and changes in oceanic and atmospheric continuing to the present, and was circulation, to document industrial designed to investigate the spatial pollution and volcanic emissions, and temporal variability in net snow- and to investigate current and past fall and the meteorological changes surface mass balance and net snow- that drive that variability. For both fall. An ice core chemical record re- logistical and scientifi c reasons, the flects changes in both emissions array includes mostly cores span- from the source regions and trans- ning the last few decades, with a port pathways, so arrays of ice core few extending over recent centuries. records are required to distinguish The majority of the ice cores were between these often covarying phe- collected from higher accumulation, Fig. 1: Map showing locations of the NGT nomena. Moreover, arrays of ice (shallow cores: red squares, deeper cores: data sparse areas of the central and cores offer the potential to identify blue squares) and PARCA (shallow cores: red southern GIS, where altimetry mea- spatial variability in emissions, cli- triangles, deeper cores: blue triangles) arrays surements indicate the most change of ice cores in Greenland. Cores identifi ed as mate, and meteorology. Extensive shallow are less than 50 m in depth. Cores (Fig. 1). For validation of satellite arrays of ice cores (Fig. 1) have been funded by NSF (deeper cores: blue diamonds) and meteorological model estimates collected recently on the Greenland and EGIG (shallow cores: red stars) are shown of net snowfall, a multi-parameter Ice Sheet (GIS) under two projects: for completeness. approach to dating is used that in- the Alfred-Wegener-Institute North nitrate and sulfate (Fig. 2) and the cludes high-resolution chemical Greenland Traverse (NGT) (follow- impact of industrial emissions on measurements from traditional and ing the 1990 to 1992 German/Swiss north Greenland precipitation. More expanded continuous fl ow analysis glaciological study along the old recently, measurements of sea salt (CFA), together with discrete water line of the Expedition Glaciologique tracers from the NGT deeper cores isotope, beta radiation, and dust International au Groenland (EGIG) were used to investigate interannu- particle measurements for some in central Greenland) and the U.S. al to multidecadal modes in atmo- cores. Program for Arctic Regional Climate sphere/ocean dynamics in the North Although the primary focus of Assessment (PARCA). Atlantic over the past millennium PARCA has been on snowfall and (Fischer and Mieding, 2005). mass balance, the array also pro- North Greenland traverse The NGT array includes 33 shallow 250 and 13 deeper ice cores collected as 200 2- part of 1993 to 1995 overland travers- ] SO4 es in the data sparse northern GIS - NO3 (Fig. 1). Isotopic and glaciochemical 150 analyses on selected cores included 18 discrete measurements of δ O, and 100 major and trace ions, which have been used to address a range of 50 geophysical issues. For example, the cores were used to document firn concentration [ppb the preindustrial climate variability 0 and precipitation history in northern 1800 1850 1900 1950 2000 Greenland (see below). Fischer et al. Year (1998) analyzed the array to charac- Fig. 2: Long-term trend in sulfate and nitrate concentrations in the NGT B21 (80.0°N, 41.1°W) terize deposition mechanisms for core.

PAGESPAGES NEWSEWS, VOLOL.14,.14, NN°1,°1, APRILPRIL 22006006 14 Science Highlights: Ice Core Science

to develop both long-term mean (e.g., Bales et al., 2001; Dethloff et al., 2002) and year-by-year maps of net snowfall for all or parts of the ice sheet, to validate meteorological model estimates of net snowfall, and to interpret repeat altimetry surveys. For example, using year-by-year accumulation records from ice cores, together with fi rn densifi cation modeling, it was found that much of the 1978 to 1988 spatial pattern in ice- sheet elevation change observed by repeat altimetry could be attributed to short-term variability in snowfall (McConnell et al., 2000), with such elevation change masking any thickening and thinning associated Fig. 3: High-resolution record of lead concentration and lead enrichment (relative to aluminum) with long-term, ice-dynamics-driven measured in the PARCA ACT2 ice core (66.0°N, 45.2°W). changes in mass balance. More re- vides a unique spatially distributed tial variability in net snowfall on the cently, net accumulation measure- record of precipitation and atmo- GIS. To date, results have been used ments have been used to validate the spheric chemistry, dust and sea salt ERA-40 reanalysis. Results indicate fl ux, and volcanic fallout. Particularly, Project facts that, as with other meteorological recently collected cores have been PARCA - Program for Regional Climate model outputs, ERA-40 simulations analyzed with a newly developed Assessment) capture much of the temporal vari- CFA system that also includes trace Contact: Joe McConnell, [email protected] ability in snowfall but not the mag- Participants: Roger Bales (University of elements. For example, the records nitude of snowfall around the ice California, Merced), Joe McConnell (Desert document dramatic changes in lead Research Institute), Ellen Mosley-Thomp- sheet (Hanna et al., 2005). pollution in Greenland precipitation son (Ohio State University) over recent decades to centuries in Funding: NASA, with additional support from REFERENCES response to industrialization and the NSF Bales, R.C., McConnell, J.R., Mosley-Thompson, E. Where: Greenland and Lamorey, G., 2001: Accumulation map for the effi cacy of subsequent government Greenland Ice Sheet: 1971-1990. Geophysical interventions in the early 1970s (Fig. When: 1995-present Research Letters, 28: 2967-2970. What: >80 shallow to intermediate ice cores 3). Interpretations of the chemical Dethloff, K., Schwager, M., Christensen, J. H., spanning decades to the last millennium, Kiilsholm, S., Rinke, A., Dorn, W., Jung-Rothen- measurements from the PARCA ice Traditional CFA, dust concentration, water häusler, F., Fischer, H., Kipstuhl, S. and Miller H., core array are ongoing and will ad- isotopes, beta horizons for earlier cores, 2002: Recent Greenland accumulation estimated dress a range of environmental and Expanded CFA for more recent cores from regional climate model simulations and ice core results, Journal of Climate, 15: 2821-2832. paleoclimate questions. including >20 elements and chemical species measured at ~1 cm effective depth Fischer, H. and Mieding, B., 2005: A 1,000-year ice core resolution. record of interannual to multidecadal variations in atmospheric circulation over the North Atlantic. New GIS accumulation estimates Web Page: http://nsidc.org/data/parca/ The Greenland Ice Sheet (GIS) con- Climate Dynamics, 25: 65-74. Fischer, H., Wagenbach, D., and Kipfstuhl, J., 1998: tains enough ice to raise sea level by NGT - North Greenland Traverse Sulfate and nitrate fi rn concentrations on the Green- 7 m, so understanding the current Contact: Sepp Kipfstuhl, land ice sheet: 1. Large scale geographical deposi- and past mass balance is critical to [email protected] tion changes. Journal of Geophysical Research, 103(D17): 21927-21934. sea level prediction. Recent repeat Participants: Sepp Kipfstuhl, Hubertus Hanna, E., McConnell, J., Das, S., Cappelen, J. and altimetry studies show little change Fischer (Alfred-Wegener-Institute for Polar Stephens A., 2005. Observed and modeled Green- and Marine Research, Bremerhaven), in overall mass at higher elevations, land Ice Sheet snow accumulation, 1958-2003, Dietmar Wagenbach (Institute for Environ- and links with regional climate forcing. Journal of although some areas have experi- mental Physics, University of Heidelberg), Climate, in press. enced signifi cant thinning or thick- Thomas Stocker (Climate and Environmen- McConnell, J.R., Arthern, R.J., Mosley-Thompson, E., ening during the past few decades. tal Physics, Physics Institute, University of Davis, C.H., Bales, R.C., Thomas, R., Burkhart, J.F. However, multiple factors determine Bern) and Kyne J.D., 2000: Changes in Greenland ice- Funding: National contributions from Ger- sheet elevation attributed primarily to snow-accu- ice sheet elevation change, includ- mulation variability. Nature, 406: 877-879. many and Switzerland ing changes in ice dynamics and Where: Northern Greenland melt, as well as short and long-term When: 1993-95 changes in net snowfall. What: Snow pits, shallow and intermediate Ice-core accumulation measure- ice cores spanning up to 1000 years, water ments from the PARCA and NGT isotopes (δ18O, δD, deuterium excess), arrays provide a much better under- major and traces, radioisotopes standing of the temporal and spa- Database: www.pangaea.de

PAGES NEWS, VOL.14, N°1, APRIL 2006 Science Highlights: Ice Core Science 15

NGRIP ice core reveals detailed climatic history 123 kyrs back in time

DORTHE DAHL-JENSEN Niels Bohr Institute, University of Copenhagen, Denmark; [email protected] Introduction In 2003, for the fi rst time, an undis- turbed Greenland ice core record reaching further back than the glacial period was completed. The 3090 m long ice core from NGRIP, on the northern part of the Greenland Ice Sheet, contains layers of snowfall from the last 123,000 years. The annual layers close to the surface are 0.19 m thick, corresponding to the present accumulation rate (in ice equivalent) and the annual lay- Fig. 1: The δ18O record from NGRIP (black) (NGRIP members, 2004) on the GICC05 timescale down to 2128.28 m (age 41,760 yr b2k) and below on a timescale based on a fl ow model that ers at the base are all around 1 cm has been tuned to the GICC05 timescale. The synchronized δ18O record from GRIP (gray) is thick. The basal annual layer thick- shown down to 105,000 yr b2k so the two records can be compared. Some of the Dansgaard- ness is so well preserved due to a Oeschger warm stages (DO) are shown, and the Younger Dryas (YD), Holocene and Eemian climatic periods are marked. basal melt of 7 mm/yr, reducing the thinning near the bed (Dahl-Jensen extent of the Laurentide ice sheet, to resolve these layers to gain un- et al., 2003). This very high-resolu- sea ice and the extensive North At- derstanding of the climate system tion record contains 1490 m of ice lantic ice shelves, NorthGRIP shows and to produce a timescale based from the present interglacial period a more continental climate regime on counted annual layers. Chemical (0-11,703 yr b2k (before AD 2000)), and may have seen a higher fraction measurements using Continuous 1600 m of ice from the glacial period of air coming over the northern side Flow Analysis (CFA), including dust (11,703-115,000 yr b2k) and 90 m of of the Laurentide ice sheet, bringing and ECM on the melt water, visual ice from the last interglacial period, with it colder and more isotopically stratigraphy (VS) and ECM on the the Eemian climatic period (NGRIP depleted moisture than GRIP might frozen ice cores make it possible to members, 2004) have seen. Taken as a whole, the resolve the annual layers down to 60 fi ndings here suggest that the atmo- kyr b2k and perhaps further (Fischer The NGRIP isotope record spheric water cycle over Greenland is et al., 2006; Rasmussen et al., 2005). The stable isotope record from the substantially different between mod- The highly resolved records reveal NGRIP ice core is measured in 5 cm ern and glacial worlds. The bottom that the abrupt climate changes like resolution. Down to a depth of 2900 90 m of the NGRIP ice core contains the warmings into DO events, the m (105 kyr b2k), the record shows ice from the last interglacial period. transition into the Bølling/Allerød the same general climatic features The isotopic value of this ice is high and from the Younger Dryas into the as observed in other Greenland ice and corresponds to temperatures 5K Holocene happened over very short cores, including the Younger Dryas, higher than the present. The part of periods, sometimes only a few years. the Bølling Allerød and the 24 abrupt the Eemian period from 123-115 kyr The highest resolution record is the and climatic warm Dansgaard/Oe- b2k found in the NGRIP ice core re- visual stratigraphy with a resolution schger (DO) events during the gla- veals that the period was warm and of 0.1 mm (Svenson et al., 2005). The cial period (NGRIP members, 2004). stable. The decline to glacial condi- annual layers can be seen here down Whereas NorthGRIP and GRIP have tions happened slowly over 5000 to 100 kyr b2k. The visual record also very similar δ18O levels during the years. It is interesting to note how clearly demonstrates that the stratig- Holocene, glacial isotopic levels in soon the DO events begin to infl u- raphy is preserved through the full the NorthGRIP record are systemati- ence the climatic pattern. The fi rst to NGRIP ice core. cally depleted by 1-2‰. The magni- be found at a depth of 3040 m (age A new Greenland Ice Core Chro- tude of the difference appears to be 114 kyr b2k) might have happened nology (GICC05) covering the last related to the Northern Hemisphere before the full build up of the big gla- 41 kyr has been constructed from climate curve, as represented by a cial ice sheets was reached. stratigraphic annual layer counting smoothed version of the NorthGRIP of high-resolution records from the record, such that colder conditions Stratigraphic dating of the NGRIP ice core and from GRIP and have larger differences. A spatial pat- NGRIP ice core Dye3 (Rasmussen, in press). Dating tern of glacial climate over Greenland The very high resolution of the of the Holocene period back to the begins to unfold. Our best theory is NGRIP ice core allows identifi cation 8.2 kyr event is based partly on exist- that the air masses reaching the two of the single annual layers down ing and partly on new stable isotope sites during the glacial were from through large parts of the ice core. measurements of the Dye-3 (GISP1) different sources. In response to the One of the goals of NGRIP has been ice core. For the interval 8.2-10 kyr

PAGES NEWS, VOL.14, N°1, APRIL 2006 16 Science Highlights: Ice Core Science

b2k, the timescale has been obtained from Electrical Conductivity Mea- surements (ECM) of the solid ice and multiparameter chemical CFA of the GRIP ice core. Beyond 10 kyr b2k, the timescale is based on records from the NGRIP ice core: An extended spectrum of chemical paramaters using CFA, ECM, and the light intensity curve of the recorded VS. At any depth, the dating is based on the ice core with the best available high-resolution data, and the three ice cores are tied together using unambiguous reference horizons, such as volcanic Fig. 2: As an example of the high-resolution data along the NGRIP ice core, data from the ash layers or major acidity spikes. visual stratigraphy using the line scan instrument (a) is shown. A 50 cm long section of the The maximum counting error at 41 record is shown in (b). TThehe record is from 2358.0-2358.5 m where the age is 57 kyrkyr b2k and kyr b2k is 1600 years. The new times- the mean annual thickness is 1.2 cm. cale places the Holocene/Pleistocene the ice sheet formation. Many ad- outstanding results and will soon be transition at 11,703 yr b2k, the onset ditional parameters like the gases, published. of Greenland Interstadial 3 (GIS3) at deuterium, deuterium excess, dust, 27.8 kyr b2k, and the onset of GIS8 at as well as detailed comparisons with REFERENCES Dahl-Jensen, D., Gundestrup, N., Gogineni, P. and 38.3 kyr b2k. the Antarctic ice cores, are revealing Miller, H., 2003: Basal melt at NorthGRIP modeled from borehole, ice-core and radio-echo sounder Outlook Project facts observations. Annals of Glaciology, 37: 207-212. Fischer, H., Siggard-Andersen, M.L. and Ruth U., At the base of the 3090 m thick ice Project: North Greenland Ice Core Project submitted: Glacial/interglacial changes in mineral sheet, the ice is melting and when (NGRIP) dust and sea salt records in polar ice cores: sources, bedrock was reached in 2003, basal Contact: Dorthe Dahl Jensen, [email protected] transport, and deposition. Reviews of Geophysics. water ﬂ ooded the lowest 45 m of the Participants: Numerous scientists from labo- North Greenland Ice-Core Project (NorthGRIP) Mem- ratories in 8 European nations and the USA. bers, 2004: High resolution Climate Record of the borehole (Dahl-Jensen et al., 2003). Northern Hemisphere reaching into the last Glacial The reddish refrozen basal water Funding: Funding agencies in Denmark Interglacial Period. Nature, 431: 147-151. (SNF), Belgium (FNRS-CFB), France (IPEV from the sub-glacial water system Rasmussen, S. O., Andersen, K. K., Svensson, A. M., and INSU/CNRS), Germany (AWI), Iceland Steffensen, J. P., Vinther, B. M., Clausen, H. B., in the lowest 45 m of the borehole (RannIs), Japan (MEXT), Sweden (SPRS), Andersen, M. -L., Johnsen, S. J., Larsen, L. B., Bigler, was recovered by drilling in 2004 Switzerland (SNF) and the USA (NSF, Ofﬁ ce M., Röthlisberger, R., Fischer, H., Goto-Azuma, K., and two macroscopic plant remains of Polar Programs) Hansson, M. E. and Ruth, U., 2005: A new Greenland Where: Northern Greenland ice core chronology for the last glacial termination, were recovered from the NGRIP core. Journal of geophysical research. in press. When: drilling 1996-2003, analysis ongoing. One is a wood fragment of willow Svensson, A., Wedel Nielsen, S., Kipfstuhl, S., John- What: 3090 m ice core from surface to bed- (Salix) and the other is a fragment son, S.J., Peder Steffensden, J.P., Bigler, M., Ruth, rock, multiparameter analysis U. and Röthlisberger, R., 2005: Visual stratigraphy of a bud scale, probably also from Web page: www.glaciology.gfy.ku.dk/ngrip/ of the North Greenland Ice Core Project (NorthGRIP) willow. Also, a few tiny fragments index_eng.htm ice core during the last glacial period. Journal of of spruce or larch (Picea/Larix) werewere Database: www.glaciology.gfy.ku.dk/ngrip/ Geophysical Research 110, D02108, doi:10.1029/ found, potentially representing an- index_eng.htm 2004JD005134. cient vegetation from the time of

Paleoenvironmental reconstruction from Alpine ice cores

MARGIT SCHWIKOWSKI Paul Scherrer Institute, Villigen, Switzerland; [email protected] Introduction Austria, into Slovenia. The total potential ice core sites are limited The European Alps, located in number of glaciers is 5422, cover- to a few high-elevation areas, such South-Central Europe, extend 800 ing an area of 3010 km2 (Paul et al., as the Bernese Alps, and the Monte km in the west-east and 150-200 2004). Glaciers with sufﬁ ciently cold Rosa and Mont Blanc areas. km in the north-south direction (44- ﬁ rn temperatures, where melt-water The Alps are especially interest- 48°N, 5.5-16°E). They form a great percolation is negligible and which ing for ice core studies because arc from the Riviera coast on the are therefore suitable for ice core a dense network of instrumental Mediterranean Sea, along the bor- studies, can be found above 4000 m meteorological measurements ders of northern Italy and adjacent asl in the northern part and above is available there and in the sur- regions of southeast France, Swit- 4300 m asl in the southern part of rounding countries. The existence zerland, southwest Germany and the Alps (Suter et al., 2001). Thus, of such exclusive data sets is a ma-

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Fig. 1: Ice core drilling camp on Fiescherhorn glacier, Swiss Alps, in December 2002. (Photo A. Schwerzmann) jor advantage compared to other up of Pleistocene ice. However, the activities and their possible impact 18 ice core sites, since the ice core δ O values of O2 entrapped in air on climate are most pronounced in climate proxy records can be cali- bubbles are not as high to unequiv- industrialized areas. Detailed stud- brated. This is extremely important ocally conﬁ rm this hypothesis (M. ies have been conducted on atmo- for an improved understanding of Leuenberger, personal communica- spheric transport from the emission the characteristics of the glacier ar- tion). source areas to the high altitudes, chives. Some of the instrumental where the glacier archives are lo- records reach back over 250 years Results cated. They show that the high- (Böhm et al., 2001). Not only tem- An important aspect of Alpine ice altitude aerosol concentration, and perature data but also precipitation cores is their proximity to emission subsequently also the concentration data are available and, furthermore, sources of anthropogenic pollution. of aerosol constituents in snow and historical air quality measurements Especially for aerosol particles and ice, is mainly controlled by the sea- exist. related gaseous species, with short sonally varying intensity in vertical atmospheric lifetimes, changes in mixing (see e.g. Baltensperger et al., Drill sites the atmospheric load due to human 1997). Therefore, the seasonal am- Mean annual precipitation in the Alps varies between 500 and 3000 mm. Accordingly, relatively high an-

nual net accumulation rates were L 100

/ observed at most of the ice core g � 50 sites, i.e. ~1.3 m water equivalent Black carbon (weq) at Fiescherhorn glacier (Fig. 0 1), Bernese Alps, ~1.5 m weq at Col 3

du Dôme, Mont Blanc, ~1.6 m weq L / 2

at Lys Glacier, ~2.7 m weq at Gren- � 1 Lead zgletscher, both Monte Rosa area, and ~2.6 m weq at Piz Zupó, Bernina 0 area. With typical glacier thickness-

L 0.2 es of 80 to 150 m in the accumu- / g Ammonium lation areas, ice core records from m 0.1 these sites cover rather short time 0.0 periods of, at best, a few hundred years. A noteworthy exception is

L 0.4 the Colle Gnifetti glacier saddle in / g Nitrate the Monte Rosa area on the border m 0.2 between Switzerland and Italy. Due 0.0 to the preferential wind erosion of dry winter snow the annual snow

/ 0.6 accumulation is in the order of g exSulphate only 30 cm weq, implying preser- m 0.3 vation of potentially more than the 0.0 last 1000 years at reasonable time 1800 1850 1900 1950 2000 resolution. Indeed, 3D glaciological Year AD ﬂ ow models indicate that the ice Fig. 2: Concentration trends of ex-sulphate, nitrate, ammonium, lead, and black carbon in ice close to bedrock is more than 2000 cores from Colle Gnifetti, Swiss Alps. Ex-sulphate represents sulphate corrected for the sea-salt years old (Lüthi and Funk, 2000). and mineral dust contribution and is assumed to originate exclusively from oxidation of sulphur Here, a dramatic decrease of δ18O dioxide in the atmosphere. Given are 5-year averages (one 4-year average for 2000-2003; composite records from cores drilled in 1982 and 2003), except for lead (10-year averages from values (Wagenbach, 1994) suggests 1800-1900, composite record from cores drilled in 1982 and 1995 (Schwikowski et al, 2004)) that the basal layer may be made and black carbon (10-year averages, from a core drilled in 1982 (Lavanchy et al., 1999)).

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plitudes of aerosol concentrations are large compared to their long- Project facts term trends. This also applies to the temperature refl ected in the stable CARBOSOL - PPresentresent aandnd RRetrospectiveetrospective SStatetate Funding: European Community, of Organic versus Inorganic Aerosol over isotope ratios in precipitation. coordinator: Reinhard Böhm Europe: Implications for climate (long term When: 2002-2006 Various concentration records of ice core records of organic aerosol species) Web page: www.zamg.ac.at/ALP-IMP a number of chemical trace species Contact: Michel Legrand and gases obtained from the dif- [email protected] Klimageschichte im Alpenraum - aausus ferent Alpine ice cores have been Participants: LGGE-Grenoble, IUP Heidelberg Analysen von Eisbohrkernen published. These records clearly Funding: European Community Contact: H.W. Gäggeler, demonstrate the impact of anthro- coordinator: Michel Legrand [email protected] pogenic emissions on the impurity When: 2002-2005 Participants: Paul Scherrer Institut and KUP content of snow. They show a gen- Web page: www.vein.hu/CARBOSOL/ Funding: Swiss National Science Foundation erally consistent picture of a vastly When: 1993-1996 ALPCLIM - EEnvironmentalnvironmental aandnd CClimaticlimatic altered atmospheric composition Records from High Elevation Alpine Glaciers, VITA - VVarves,arves, IceIce ccores,ores, aandnd TTreeree rringsings due to industrialization. This is the (glacio-chemical and stable isotope studies – Archives with annual resolution case for major aerosol components at Monte Rosa and Mt.Blanc) Contact: Margit Schwikowski, such as sulphate, nitrate, ammoni- Contact: Susanne Preunkert, [email protected] um, and carbonaceous particles as [email protected] Participants: Paul Scherrer Institut, well as trace substances, for exam- Participants: LGGE-Grenoble,University University of Bern Zürich,VAW/ETH-Zürich, KUP-University ple, heavy metals, fl uoride, chloride, Funding: Swiss National Science Foundation Bern, DISAT-Milano, IUP Heidelberg (in the frame of the NCCR Climate Program) and radionuclides. Furthermore, the Funding: European Community presence of organochlorine pesti- When: 2002-2005 coordinator: Dietmar Wagenbach Web page: www.nccr-climate.unibe.ch/ cides in Alpine ice has been shown When:1997-2001 (Villa et al., 2003). Most of the pol- Web page: www.geo.unizh.ch/~hoelzle/ VIVALDI - VVariabilityariability iinn IIce,ce, VVegetationegetation aandnd lutants have a concentration maxi- Lake Deposits – Integrated mum in the 1970s and early 1980s, ALP-IMP - MMulti-Centennialulti-Centennial CClimatelimate VVariabil-ariabil- Contact: Margit Schwikowski, and responded to air pollution ity in the Alps based on Instrumental Data, [email protected] Model simulations and Proxy Data (stable control measures in Europe (such Participants: University of Bern, isotope studies on deep Monte Rosa and Paul Scherrer Institut, EAWAG as introduction of fi lters, catalytic Mt. Blanc cores) Funding: Swiss National Science Foundation converters, unleaded fuel) with a Contact: Dietmar Wagenbach, (in the frame of the NCCR Climatep pogram) downward trend in concentration, [email protected] When: 2005-present as illustrated in Figure 2 with the ex- Participants: University Zürich,LSCE- Saclay, Web page: www.nccr-climate.unibe.ch/ amples of sulphate, lead, and black IUP Heidelberg carbon. Notable exceptions are nitrate (see e.g. Preunkert et al., 2003) of nitrate: Comparison with anthropogenic invento- and ammonium, which are still at a 150 years, with a concentration in- ries and estimation of preindustrial emissions of high level. In the case of nitrate, re- crease by a factor of 13 between the NO in Europe, J. Geophys. Res., 108 (D21): 4681. Schwikowski, I., Barbante, C., Doering, T., Gäggeler, duction of NOx emissions in individ- pre-industrial and industrial period. H.W., Boutron, C., Schotterer, U, Tobler, L., Van De ual cars has been counterbalanced The level in the Alps in the period Velde, K.V., Ferrari, C., Cozzi, G., Rosman, K. and by increasing traffi c. Ammonium of maximum industrial emissions Cescon, P., 2004: Post-17th-century changes of originates from agricultural activi- is about a factor of fi ve higher than European lead emissions recorded in high-altitude alpine snow and ice, Environ. Sci. Tech., 38 (4): ties, such as animal manure and fer- in Greenland ice cores, whereas in 957-964. tilizer application, where no control Antarctica no anthropogenic sul- Villa, S., Vighi, M., Maggi, V., Finizio, A. and Bolzac- measures have been introduced. phate could be detected (Cole-Dai chini, E., 2003: Historical trends of organochlorine Ice core derived concentration et al., 2000). pesticides in an Alpine glacier, J. Atmos. Chem., 46 (3): 295-311. records of aerosol species have Wagenbach, D., 1994: Results from the Colle Gnifetti been used to estimate the aerosol REFERENCES ice-core programme, in: ESF/EPL Workshop on effect on climate. For this purpose, Böhm, R., Auer, I., Brunetti, M., Maugeri, M., Nanni, Greenhouse gases, isotopes and trace elements T. and Schöner, W., 2001: Regional temperature in glaciers as climatic evidence of the Holocene, records from mid-latitude glaciers variability in the European Alps: 1760-1998 from edited by W. Haeberli, Stauffer, B., VAW Arbeit- are extremely important. On the one homogenized instrumental time series, Int. J. sheft: 19-22, Zürich. hand because only few long-term re- Clim., 21 (14): 1779-1801. Lüthi, M., and Funk, M., 2000: Dating ice cores from a cords of tropospheric aerosols exist, For full references please consult: high Alpine glacier with a fl ow model for cold fi rn, www.pages-igbp.org/products/newsletters/ref2006_1.html and on the other hand because data Annals of Glaciology, 31: 69-79. from the emission source areas are Paul, F., Kaab, A., Maisch, M., Kellenberger, T. and Haeberli, W., 2004: Rapid disintegration needed due to the regional nature of Alpine glaciers observed with satellite data, of aerosol concentrations. Sulphate Geophys. Res. Lett., 31 (21), L21402, doi:10.1029/ concentrations in ice cores from the 2004GL020816, Alps display the strongest anthro- Preunkert, S., Wagenbach, D., and Legrand, M., 2003: A seasonally resolved alpine ice core record pogenic infl uence during the last

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South American Andes: A unique area for ice core-based tropical paleoclimate reconstruction

FRANÇOISE VIMEUX AND PATRICK GINOT IRD Great Ice, Lab. des Sci. du Climat et de l’Environm., Gif-sur-Yvette, France; [email protected]; [email protected]

Introduction The Andean summits stretch out along about 7000 km of South America in a north-south transect from northern hemisphere low latitudes (Columbia, 5°N) to southern hemisphere high latitudes (south Chile, 55°S). Along this natural atmospheric circulation boundary, a large number of peaks reaching between 5000 m and 7000 m are covered with glaciers but only a few of them in Ecuador, Peru, Bolivia, Chile and Argentina are suitable for ice core paleoclimate investigation. The An- des are a specifi c area in the tropics where both Atlantic and Pacifi c infl u- ences on past climate variations can be explored. This is mainly because the atmospheric circulation can be roughly divided in two components (e.g. Montecinos et al., 2000): (i) north of 20°S, tropical NE-winds or Trade winds transport Atlantic Ocean moisture over the Amazonian basin to the Andes, (ii) south of 20°S, Pacifi c Ocean moisture is directly transported by SW westerly winds. Polar front inputs may also infl uence the southern Andes. Between these two areas, the South American Arid Diagonal is one of the driest regions in the world, where no glaciers exist. Thus, tropical ice cores are likely to contain information on both the Intertropical Convergence Zone and Hadley cells, and ENSO in the Pacifi c Ocean. Important modifi cations of this system started a few decades ago and will intensify in connection Fig. 1: Location of deep drilling sites where ice cores were extracted along the South Ameri- with industrial and agricultural de- can Andes. Arrows indicate the main atmospheric circulation paths, map colors illustrate the velopment (IPCC, 2001). A detailed mean annual precipitation knowledge of the background state Lonnie Thompson (Byrd Polar Re- teorologia y Hidrologia – Ecuador, of the area (before anthropogenic in- search Center - OSU) pioneered Servicio Nacional de Meteorologia fl uence) is essential to understand these activities in 1983 on the e Hidrologia – Peru, Centro de Es- the anthropogenic effect on climate Quelccaya glacier (Peru), followed tudios Cientifi cos – Chile, etc.) have changes. In this context, a compre- by Huascarán (Peru) and Sajama joined this effort to extend the ice hensive study of Andean ice cores (Bolivia). Since 1997, other institu- core investigation on Cerro Tapado is essential to provide a comprehen- tions (Institut de Recherche pour le (Chile), Illimani (Bolivia), Chimbo- sive spectrum of climatic and envi- Développement - Great Ice – France, razo (Ecuador), Mercedario (Argen- ronmental proxies. Paul Scherrer Institut – Switzerland, tina) and Coropuna (Peru), in order Over the last few decades, sev- and their South American partners: to reconstruct a latitudinal transect eral institutions have developed Instituto Hydraulica y Hidrologia - of paleoclimate records (Fig. 1). A ice-coring programs in the Andes. Bolivia, Instituto Nacional de Me- new deep ice core program is being

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�� teresting result is the water stable �� isotope decadal signal over the 20th century common to all the ice cores �� (Quelccaya, Huascarán, Sajama and �� Illimani) (Hoffmann et al., 2003).

�� This Andean Isotopic Index (Fig. 2) �� is fairly well reproduced by atmo- �� spheric general circulation models � �� (AGCM) and, according to recent studies dealing with both direct ob- �� servations (Vimeux et al., 2005) and AGCM (Vuille and Werner, 2005), it �� should be related to past humidity

�� changes in tropical South America �� and over the tropical Atlantic Ocean. However, when the reconstruction Fig. 2: Andean Isotope Index calculated from δ18O records from Illimani, Sajama, Huascaran, Quelccaya and δ18O of water vapor over the Amazonian region as simulated by the atmospheric reaches a high temporal resolution, general circulation model ECHAM 4. For both curves, the dotted line is raw data, the solid line such as seasonal variations, some is the 5-year running average (adapted from Hoffmann et al., 2003). important post-depositional effects developed at mid-latitudes to fi ll the teleconnections could explain such like those resulting from high sub- gap between the Andes and Antarc- similar climate changes. limation affecting chemical prox- tica (summits of San Valentin, Chile Tropical ice cores also offer a ies have to be considered (Ginot et and San Lorenzo, Argentina). Thus, high temporal resolution (seasonal al., In press; Ginot et al., 2001). The ice from the South American Andes resolution over the last centuries), impact of such effects on isotope is a climate archive that can offer a allowing a detailed study of specifi c records is highly dependent on the continuous record of our past cli- events or periods, such as the Little drilling sites (Stichler et al., 2001; F. mate, with identical proxies, from Ice Age or the last few centuries. For Vimeux, pers. comm.). Accordingly, the equator to high latitudes. example, the isotopic composition further systematic studies on tropi- of the ice (δD and δ18O), insoluble cal ice cores sites are needed to fully Results from Andean ice cores dust mass and ice core stratigraphy exploit this unique high-resolution The different programs have dem- were the fi rst proxies investigated natural climate archive. onstrated well that tropical ice cores in the Quelccaya ice core and al- can be dated, analyzed and inter- lowed a 1000-year accumulation REFERENCES preted in terms of climate changes. history reconstruction in the Andes De Angelis, M., Simões, J. C., Bonnaveira, H., Taupin, J. D., and Delmas, R. J., 2003: Volcanic erup- For dating, a combination of differ- (Thompson et al., 1985). Another in- tions recorded in the Illimani ice core (Bolivia): ent methods is typically applied: an- 1918–1998 and Tambora periods. Atmospheric nual layer counting, identifi cation Chemistry and Physics, 3: 1725-1741. Project facts Ginot, P., Kull, C., Schotterer, U., Schwikowski, M., and of reference horizons, such as past Gäggeler, H. W., in press: Glacier masse balance thermo-nuclear tests and volcanic Project: Andean ice core investigations reconstruction by sublimation induced enrichment eruptions (De Angelis et al., 2003), of chemical species on Cerro Tapado (Chilean Contact: Patrick Ginot, Andes). Climate of the Past. and radionuclide decay (Knüsel et [email protected], Knüsel, S., Ginot, P., Schotterer, U., Schwikowski, M., al., 2003). Chemical and isotopic Lonnie Thompson, [email protected], Gaeggeler, H. W., Francou, B., Simões, J. C., Petit, analyses on these ice cores strongly M. Schwikowski, [email protected] J. R., and Taupin, J. D., 2003: Dating of two nearby Participants: IRD Great Ice, LGGE, LSCE ice cores from the Illimani, Bolivia. Journal of suggest that the tropics have par- Geophysical Research, 108: 4181. (France), Byrd Polar Research Center (USA), ticipated in the well-known climate Montecinos, A., Diaz, A., and Aceituno, P., 2000: Paul Scherrer Institut, University Bern transitions over the last 20,000 Seasonal Diagnostic and Predictability of Rainfall in (Switzerland), and South American partners years. The Sajama record goes back Subtropical South America Based on Tropical Pacifi c IHH (Bolivia), SENAMHI (Peru), INAMHI SST. Journal of Climate, 13: 746-758. to around 25,000 years (Thompson (Ecuador), CECS (Chile) Stichler, W., Schotterer, U., Fröhlich, K., Ginot, P., Kull, et al., 1998) and is the oldest recon- Funding: IRD, The Award for Enterprise Rolex C., Gäggeler, H. W., and Pouyaud, B., 2001: The infl u- struction along the Andes but other for Chimborazo operation, NSF, Paul Scher- ence of sublimation on stable isotopes records from high altitude glaciers in the tropical Andes. Journal records from Huascarán (Thompson rer Institut, University Bern (Switzerland). Where: Andes of Geophysical Research, 106: 22613-22621. et al., 1995), Illimani (Ramirez et al., Thompson, L. G., Davis, M. E., Mosley-Thompson, When: Since 1974 2003) and Coropuna (P. Ginot, pers. E., Sowers, T. A., Henderson, K. A., Zagorodnov, What: Ice cores back to LGM, Multiproxy V. S., Lin, P.-N., Mikhalenko, V. N., Campen, R. K., comm.) also cover the last glacial studies. Bolzan, J. F., Cole-Dai, J., and Francou, B., 1998: A transition and interestingly show Web page: www.mpl.ird.fr/hydrologie/greatice/ 25000-year tropical climate history from Bolivian similar isotopic variations compared www-bprc.mps.ohio-state.edu/Icecore/, ice cores. Science, 282: 1858-1864. with polar ice cores (a glacial maxi- http://lch.web.psi.ch/index.html mum, a deglaciation interrupted by Database: www-bprc.mps.ohio-state.edu/ For full references please consult: a “reversal” event, a Holocene opti- Icecore/dataandimages.html www.pages-igbp.org/products/newsletters/ref2006_1.html mum). The open question is which

PAGES NEWS, VOL.14, N°1, APRIL 2006 Science Highlights: Ice Core Science 21

Dating ice cores

JAKOB SCHWANDER Climate and Environmental Physics, Physics Institute, University of Bern, Switzerland; [email protected] Introduction 200 [ppb An accurate chronology is the ba- NO

100 3 ] sis for a meaningful interpretation - 80 ] of any climate archive, including ice 2 0 O

2 40 [ppb cores. Until now, the oldest ice re- H 0 200 Dust covered from a continuous core is [ppb 100 that from Dome Concordia, Antarc- 2 ] ] tica, with an estimated age of over -1 1.6 0

Sm 1.2 µ

800,000 years (EPICA Community [ Conduct. 0.8 160 [ppb Members, 2004). But the recently SO

80 4 2 recovered cores from near bedrock ]

60 - ] at Kohnen Station (Dronning Maud + 40 0 Na Land, Antarctica) and Dome Fuji [ppb 20

40 [ 0 Ca (Antarctica) compete for the longest ppb 2

20 + climatic record. With the recovery of ] 80 0 + more and more ice cores, the task of ] 4 establishing a good common chro- 40 [ppb NH nology has become increasingly im- 0 portant for linking the fi ndings from 1425 1425 .5 1426 1426 .5 1427 the different records. Moreover, in Depth [m] order to create a comprehensive Fig. 1: Seasonal variations of impurities in early Holocene ice from the North GRIP ice core. picture of past climate dynamics, it Summer layers are indicated by grey lines. is crucial to aim at a common chro- al., 1993, Rasmussen et al., 2006). is assessed with such a model, then nology for all paleo-records. Here Ideally the counting uncertainty is one can construct a chronology of the different methods for dating ice on the order of 1%. the ice if past accumulation rates cores are summarized. a(z) are known. Ice fl ow modeling H dz′ Layer counting Ice is a fl uid with an empirical rela- age(z) = ∫ Due to the seasonal variation of tem- tion between stress and strain rate z ε z′ ⋅a(z') perature, sunlight or atmospheric (power law with an exponent of ap- (H is surface elevation of ice sheet) circulation, concentrations of many prox. 3, known as Glen’s law (Glen, trace substances or isotopes show 1955)). With the knowledge of all The estimate of past accumulation cyclic variations in the ice cores. In material properties and boundary rates is the Achilles’ heel of dating the ideal case, these annual cycles conditions, the plastic deforma- by fl ow models. Such estimates are can be counted many thousand tion of a glacier or ice sheet could mostly based on a functional depen- years back in time. Depending on be modeled in detail (Fig. 2). How- dence of precipitation and local tem- the conditions in the ice (tempera- ever, these boundary conditions perature (estimated from the stable ture, thinning of layers, etc.), varia- and properties are generally poorly isotope records). There are, how- tions are smoothed by diffusion or known. The bedrock topography is ever, other causes for variations in altered by chemical reactions or not resolved in suffi cient detail and past accumulation rates, like chang- clustering. Diffusion can be reversed past surface conditions (tempera- es in circulation or changes in local mathematically to a certain degree ture, precipitation) can only be es- surface topography. In order to im- by a deconvolution algorithm (John- timated indirectly. The same holds prove the accuracy of the age mod- sen, 1977), which extends the depth for the parameters that determine el, parameters can be constrained range for layer counting. Yet, there the fl ow properties, like ice temper- by assigning well-dated time hori- is always a lower limit below which ature, crystal orientation, impurities zons to corresponding depths. Such the annual variations are lost. One and basal sliding. Flow profi les at events are, e.g., glacial terminations reason for this is that wind is mixing a certain site can often be approxi- or minima of Earth’s magnetic fi eld the snow on the surface by scour- mated by simple fl ow models that that have been dated with best ing and relocation. Another reason are determined by local parame- possible accuracy on other paleo- is that the annual variations are al- ters, like ice sheet thickness, basal archives (Parrenin et al., 2001). The ready smoothed out when they are sliding, basal melting, and few pa- age uncertainty obtained by fl ow compacted to solid ice at the fi rn-ice rameters to describe the horizontal models depends on the accuracy of transition. Best accuracy for layer fl ow. These parameters are either accumulation rate estimates (in the counting is obtained by combining measured or constrained by age fi x- order of 20%) and on the existence different tracers (Fig. 1) (Fuhrer et points. If thinning εz at any depth z of local fl ow disturbances.

PAGES NEWS, VOL.14, N°1, APRIL 2006 22 Science Highlights: Ice Core Science

historic volcanic signals) to several thousand years.

Age of the gaseous records The upper 50-120 m of an ice sheet is made of consolidated snow (fi rn), permeable to air. Air occluded at the firn-ice transition is therefore substantially younger than the ice. Fig. 2: Cross-section through an idealized ice sheet. Layers are stretched and thinned by plastic This age difference can be estimated fl ow. The two highlighted layers (blue) comprise the same number of annual layers. with densifi cation/diffusion models Radiometric dating gaard-Oeschger events), variations (Schwander et al., 1997). The air at Because both layer counting and in the Earth’s magnetic fi eld or solar the fi rn-ice transition is on the order fl ow models may be subject to sys- activity, etc. Global records of meth- of one to a few decades. The age 18 tematic errors, absolute radiometric ane and δ Oatm, for example, have of the ice at the fi rn-ice transition clocks are needed. A number of ra- been used to synchronize ice core re- spans a large range of a few tens to dioactive isotopes have been used cords from Greenland and Antarctica several thousand years under pres- to estimate the age of natural ice (Blunier and Brook, 2001). ent conditions, depending mainly samples or the occluded air. These In the second half of the 19th on temperature and accumulation include fi ssion products, 3H (Tritium), century, James Croll proposed that rates. Locations with high accumu- 210Pb, 32Si, 39Ar, 85Kr, 14C, 81Kr, 36Cl, 10Be, the Pleistocene ice ages are caused lation rates and relatively high an- and Uranium series. Fission prod- by periodic changes in the Earth’s nual temperatures show the smallest ucts resulting from nuclear weapon orbit around the Sun. Milutin Mila- ages, while sites in central Antarctica testing in the atmosphere during the nkovitch improved the astronomical with accumulation rates of a few cm 1950s and 60s, can easily be detected theory, leading to a presently gen- per year show the largest ages. The by total beta-activity measurements. eral acceptance of the causality be- difference between the age of the Other radiometric dating methods tween Earth’s orbital parameters and ice and the age of the air has not re- have failed to be competitive with climate variations. There are three mained constant over time. Under current dating tools because the ini- astronomical parameters that deglacial conditions this age difference tial concentrations of the radioactive termine the latitudinal and seasonal was generally several times larger isotopes are too variable. However, variation of insolation on Earth: Pre- than at present. Due to uncertain- these methods remain interesting, cession (periods: 22, 24 kyr), Obliq- ties in estimating the accumulation e.g., to estimate the age of very old uity (41, 40 kyr), and Eccentricity (404 rate and the close-off depth in the ice near bedrock. kyr and several around 100 kyr). past, the error in the age difference Tuning to the Milankovitch cy- is around 10% Synchronisation with other cles is accomplished by changing paleo-records the chronology of a record such that REFERENCES Bender, M. L., 2002: Orbital tuning chronology for the Ice core chronologies often rely on its correlation with the target curve Vostok climate record supported by trapped gas indirect dating, i.e. by comparison (e.g. summer insolation at a certain composition. Earth and Planetary Science Letters, with other, better-dated paleo-ar- latitude) is increased. A shortcom- 204: 275-289. Blunier, T. and Brook, E. J., 2001: Timing of millennial- chives, including other ice cores. In ing of the method is the problem scale climate change in Antarctica and Greenland the ideal case, the well-dated record of overtuning. Recent orbital tuning during the last glacial period. Science, 291: 109-112. is annually laminated (Hughen et work has therefore been as con- Johnsen, S. J., 1977: In Proc. of Symp. on Isotopes and al., 1998, Zolitschka, 1998). Yet, these servative as possible (Karner et al., Impurities in Snow and Ice, Int. Ass. of Hydrol. Sci., Commission of Snow and Ice, I.U.G.G. XVI, General varved sediments are often affected 2002, Lisiecki and Raymo, 2005). The Assembly, Grenoble Aug.Sept., 1975. IAHS-AISH by hiatuses or do not extend to the uncertainty in the phasing between publication: 210-219. present but they can provide valu- paleo-records and the astronomical Johnsen, S. J., Clausen, H. B., Dansgaard, W., Fuhrer, K., Gundestrup, N., Hammer, C. U., Iversen, P., able information on the duration of cycles is on the order of 5 kyr. Ice Jouzel, J., Stauffer, B. and Steffensen, J. P., 1992: climatic events. Other archives are core records can be correlated to the Irregular glacial interstadials recorded in a new well suited for absolute dating meth- Milankovitch cycles either directly or Greenland ice core. Nature, 359: 311-313. Schwander, J., Sowers, T., Barnola, J.-M., Blunier, T., ods, like U/Th-dated speleothems or indirectly via synchronization, e.g., Malaizé, B. and Fuchs, A., 1997: Age scale of the corals. with marine sediment records (EPICA air in the summit ice: Implication for glacial-inter- The prerequisite for a correlation Community Members, 2004). Direct glacial temperature change. Journal of Geophysical with ice core records is that events tuning includes the temperature-sen- Research, 102: 19483-19494. exist in the ice core record that are sitive stable isotope ratios of the ice, 18 For full references please consult: unequivocally assignable to a syn- the δ O of oxygen in the trapped air www.pages-igbp.org/products/newsletters/ref2006_1.html chronous event in the other record. (Parrenin et al., 2001), and the O2/N2 Such events can be volcanic erup- ratio (Bender, 2002). Age uncertain- tions, Milankovitch-type variations, ties obtained by synchronization abrupt climate variations (Dans- techniques vary from one year (e.g.

PAGES NEWS, VOL.14, N°1, APRIL 2006 Science Highlights: Ice Core Science 23

Records from coastal ice cores

VIN MORGAN Antarctic Climate and Ecosystems Cooperative Research Centre, and the Ice, Oceans, Atmosphere and Climate Programme, Australian Antarctic Division, Hobart, Australia; [email protected]

Introduction Ice cores drilled on the periphery of �� the Antarctic ice sheet provide environmental records that complement �� those from deep cores from the in- �� terior of the continent. On the high plateau of East Antarctica, isolation �� from the oceanic moisture sources, low rates of snow accumulation and �� the great ice thickness allow deep ice �� cores to provide records of broad �� scale climate over multiple glacial

cycles. � ��

On the coastal slopes and low el- � �� evation parts of Antarctica, the more variable geography—surface slope, �� proximity to the ocean, domes, crests, etc.—and the generally higher �� accumulation rates and thinner ice �� results in cores having shorter records but with higher resolution, at �� least for the recent period. Coastal cores record a more regional signal, �� particularly through the deglaciation �� when rising sea level and temperature elicited different responses at �� different locations on the ice sheet. �� The dynamic coastal band, with its �� high accumulation rates and faster �� ice ﬂ ow, dominates the annual ice �� turnover of Antarctica. The mass �� balance of the coastal ice sheet, and thus its contribution to sea level Fig. 1: Isotope records from two inland sites, EPICA-DC and Vostok, two coastal sites, Taylor change, can respond rapidly to cli- Dome and Law Dome, and the Byrd record from West Antarctica. Also shown is Law Dome accumulation inferred from the dating model (van Ommen et al., 2004). Within dating errors, matic change but at the same time, EDC and Vostok show a similar pattern. Law Dome shows a similar pattern to the inland cores the slow response time of the inland from the LGM through the ACR but the δ18O increase is interrupted by a small dip at 11,500 ice sheet (which is coupled to the BP (close in time to the end of the Younger Dryas) and after the dip the increase continues until 10,000, about 2000 years after the inland cores. The Taylor Dome record, shown on the coastal ice by ice ﬂ ow) means that st9810 timescale, differs markedly from the others, showing cold glacial conditions continuing the ice sheet as a whole is still adjust- as late as 16,000, a later temperature reversal and continued warming through the Holocene. ing to the temperature and sea level However, recent results (including isotope ratios of trapped atmospheric nitrogen) suggest there were periods during the deglaciation of little or no accumulation at Taylor Dome. changes of the last deglaciation. We know from existing records (see ex- of the ice sheet have responded dif- change. In order to separate regional amples in Fig. 1) that different parts ferently to the sea level and climate climate change from changes to the Table 1: Coastal or low elevation Antarctic ice cores that reach (or are expected to reach) the ice sheet, and to obtain a quantita- Last Glacial Maximum. tive record of the ice sheet’s contri- �� bution to sea level change, we need �� additional records from the coastal �� zone. Accordingly, drilling and analyzing of coastal Antarctic cores has �� become a major task in ice core re- �� search (for a list of some of the most �� important coastal Antarctic cores see �� Table 1) Here we look at two results from �� the coastal Law Dome ice core. Both �

PAGES NEWS, VOL.14, N°1, APRIL 2006 24 Science Highlights: Ice Core Science

400 served despite the layer thinning, is � �

� their small delta age values. Delta � ��

� 350 � ��

� age is the difference between the age � �

� 300 � �

� of the air trapped as bubbles in the � � �

� 250 � � � �� ice and the age of the surrounding � � 200 �� ice, and arises because the air is only 150 trapped when the pores in the ﬁ rn 400000 300000 200000 100000 1000 800 600 400 200 0 are closed off to form closed bubbles �� by the weight of the overlying snow.

Fig. 2: Composite atmospheric CO2 concentration from 40400,0000,000 BP to 11978978 ADAD.. 40400,0000,000 BP Close-off occurs around a depth of to 2300 BP from Vostok (yellow line, Petit et al., 1999) 1000 BP to 1978 AD from the DSS, about 60 m at Law Dome so to a fi rst DE08 and DE08/2 Law Dome cores (Etheridge et al., 1996). 1978 AD to 2004 from South Pole air samples (Keeling and Whorf, 2005). DSS – red line, DE08 – blue line, DE08/2 – violet approximation—neglecting the lim- points, South Pole air – blue line. ited exchange with the atmosphere near close-off—delta age is the age of involve the high accumulation rate at clonic mode to the north of Law the ice at ~60 m. At low accumulation the core site as a key parameter. Dome. Determining how, when and inland sites, delta age can be thou- if this change occurred at different sands of years but coastal sites have The coastal accumulation regime locations is necessary because dif- been found with values as low as 40 Under present day conditions, ac- ferent precipitation mechanisms can years. Figure 2 shows records of at- cumulation on the inland plateau change the calibration of the ice core mospheric carbon dioxide concentra- is mainly in the form of “diamond recorder. tion from an inland site (Vostok) and dust”—clear sky ice crystal precipita- Further work using additional a coastal site (Law Dome). Delta age tion, principally in winter, that results cores to determine the timing and for Vostok is about 2000 years, so the from cooling of the atmosphere by the extent of this change in accumu- most recent data point is at 2300 BP. radiative loss. The low air tempera- lation mechanism will give insights At DE08 on the eastern fl ank of Law ture limits available moisture, so into changes in Antarctic climate and Dome, the accumulation rate 1.2 m inland accumulation rates are low its possible effects on the ice sheet’s of ice equivalent per year leads to and tend to follow temperature varia- mass balance. So far, the only coastal a delta age of 30 years. The coastal tion. On the coastal slopes, snowfall cores that have accumulation records Law Dome site extends the record resulting from orographic uplift of extending into the Glacial are Law up to 1978 AD, overlapping direct air moist air from cyclonic systems re- Dome and Taylor Dome. In the near composition measurements at South sults in high accumulation rates that future, we expect to be able to add Pole and delineating the increase due depend mainly on the frequency of the records from the Berkner Island to anthropogenic input. cyclones and are largely independent and Siple Dome cores and in a few of temperature. years time there will be a record from REFERENCES Law Dome projects out from the the new Talos Dome core. Etheridge, D. M., Steele, L. P., Langenfelds, R. B., Francey, R. J., Barnola, J-M. and Morgan, V. I., coast of East Antarctica and is the 1996: Natural and anthropogenic changes in most northerly part of the continent, High-resolution gas records atmospheric CO2 over the last 1000 years from air apart from the extremity of the Ant- A feature of the high accumulation in Antarctic ice and fi rn. Journal of Geophysical Research, 101(D2): 4115-4128. arctic Peninsula. Under present day coastal cores, and one that is pre- Keeling, C.D. and Whorf, T.P., 2005: Atmospheric CO2 meteorology, Law Dome receives records from sites in the SIO air sampling network. precipitation from cyclonic systems, Project facts In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis however, recent results (van Ommen Project: Deep Ice Drilling on Law Dome Center, Oak Ridge National Laboratory, U.S. et al., 2004) have shown that during Contact: Vin Morgan, [email protected] Department of Energy, Oak Ridge, Tenn., U.S.A. the Glacial and through the early Participants: Vin Morgan, Tas van Ommen, Steig, E.J. and 7 others, 2000: Wisconsinan and Mark Curran, Barbara Smith (Antarctic Holocene climate history from an ice core at Taylor Holocene, accumulation rates were Dome, Western Ross Embayment, Antarctica. only some 10% of present day and Climate and Ecosystems Cooperative Geogr. Ann., 82A(2-3): 213-235. Research Centre, and the Ice, Oceans, varied with temperature. A similar Petit, J. R., Jouzel, J., Raynaud, D., Barkov, N.I., Barnola, Atmosphere and Climate Programme, situation appears to have existed at J.-M., Basile, I., Bender, M., Chappellaz, J., Davis, Australian Antarctic Division) M., Delaygue, G., Masson-Delmotte, V., Kotlyakov, Taylor Dome, which also has a large Funding: Australian Antarctic Division V.M., Legrand, M., Lipenkov, V.Y., Lorius, C., Pepin, accumulation rate change from the Where: Coastal East Antarctica L., Ritz, C., Saltzman, E., and Stievenard M., 1999: Glacial to the Holocene (Steig and When: Drilling 1988 to 1993, core analysis Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica, Nature, others, 2000). It seems that during ongoing 399: 429-436. the Glacial, lower temperatures, What: 1200 m core from surface to ~bedrock van Ommen, T., Morgan, V. and Curran, M., 2004: 4.7 km SSW of the summit of Law Dome, more northerly paths of cyclonic sys- Deglacial and Holocene changes in accumulation multiparameter analysis at Law Dome, East Antarctica. Ann. Glaciol., 39: tems and the ice sheet expansion al- Database: http://aadc-maps.aad.gov. 359-365. lowed by lowered sea level resulted au/aadc/portal/ in a shift of the boundary between www.ncdc.noaa.gov/paleo/icecore/antarc- the inland clear-sky ice-crystal mode tica/law/law.html of precipitation and the coastal cy-

PAGES NEWS, VOL.14, N°1, APRIL 2006 Science Highlights: Ice Core Science 25

The WAIS Divide ice core: Progress and plans

JEFF SEVERINGHAUS Scripps Institution of Oceanography, University of California, San Diego, USA; [email protected] Introduction For over 20 years, the international glaciological community has recognized the need for a deep ice core from the fl ow divide in central West Antarctica. This would provide the fi rst Southern Hemisphere climate record of comparable resolution and duration to the Greenland ice cores, which have revolutionized our notion of past climate stability. It would also test models of West Ant- arctic Ice Sheet (WAIS) history and stability, a major concern for future sea level. The WAISCORES initiative was launched by the U.S. National Science Foundation in the 1990s Fig. 1: Map showing locations of the existing Byrd and Siple Dome ice cores, and the planned to realize these goals through the WAIS Divide ice core. drilling of two deep cores. The fi rst migration has compromised the stra- variations in atmospheric methane was a deep core at the coastal site tigraphy. Because this is the leeward and CO2 during the Dansgaard-Oe-

Siple Dome (Brook et al., 2005; Sev- side relative to the prevailing storm schger events. Atmospheric CO2 is eringhaus et al., 2003; Taylor et al., track, the accumulation rate at the known to respond quickly to chang- 2004), which is now complete, and site is substantially less than at the es in sea surface temperature, so the second is a deep core at the ice divide itself. This has the advantage the precise timing may shed light fl ow divide in the center of the WAIS, of making the Holocene section of on the mechanism of these events. known as the WAIS Divide core (Fig. the core more compact, and older Many other gases and their isotopes 1). This article discusses the current sections expanded, because deeper will be measured at unprecedented 13 4 state of the WAIS Divide project, the ice originated closer to the divide. precision and resolution ( CH , N2O, 15 18 17 scientifi c questions to be addressed, CH3Cl, CH3Br; N of N2. O and O 40 36 and future plans. Objectives of O2, Ar/ Ar, Kr/N2, Xe/N2 among Like GISP2, WAIS Divide is expected others). Overall the WAIS Divide core The WAIS Divide ice core drilling to yield a high-resolution record is expected to produce the best gas Site selection was recently com- of temperature and atmospheric records of the past 100 kyr yet ob- pleted for the WAIS Divide project methane during the millennial-scale tained. (see box). During the 2005-2006 (Dansgaard-Oeschger) oscillations season just finished, a camp was of the last glacial period. Because established, shallow cores were re- of the small age difference between Project facts trieved, and fi rn air sampling was the gases and the enclosing ice, a Project: WAIS conducted. A new deep drill (called decadal-precision chronology rela- Contact: Kendrick Taylor (Desert Research the DISC drill) has been constructed tive to Greenland is expected, using Institute, University of Nevada), for the WAIS Divide project and will methane and air 18O as interhemi- [email protected] be tested at Greenland summit in spheric time markers. This will allow Steering committee: Richard Alley (Penn summer 2006. This test will focus on stringent tests of the bipolar see-saw State), Ed Brook (Oregon State University), Jeff Severinghaus (Scripps Institution of optimizing core quality in the brittle hypothesis; that Atlantic ocean circu- Oceanography), Jim White (INSTAAR, ice zone, and will reach a depth of lation changes caused the apparent University of Colorado) 600 m. The 2006-2007 season will be asynchrony of Greenland and Ant- Funding: NSF devoted to drill setup at the WAIS Di- arctic climate records at millennial Where: West Antarctic Ice Sheets (WAIS vide site, and deep drilling will begin time scales. divide: 79.468°S, 112.086°W, altitude in earnest in the 2007-2008 season. One important difference from 1765m, ice thickness 3465 m When: 2006-2011 The chosen site is an almost ex- GISP2 is that an excellent atmo- What: Deep ice core covering approx. one act analog to GISP2 in Greenland in spheric CO2 record is expected to glacial cycle terms of temperature, accumulation be obtained because Antarctic ice Web page: www.dri.edu/People/kendrick/ rate, gas age-ice age difference, and has an order of magnitude less dust WDSprojmain.htm other variables. The site is ~24 km than Greenland ice. This will allow, http://igloo.gsfc.nasa.gov/wais/ downslope of the fl ow divide, simi- for the fi rst time, precise compari- http://waiscores.dri.edu/ lar to GISP2, to insure that no divide son of the relative timing of rapid

PAGES NEWS, VOL.14, N°1, APRIL 2006 26 Science Highlights: Ice Core Science

As in Greenland, the high accumula- fort. WAIS Divide is under the um- Year (2007-2008). Bottom-up, indi- tion rate and great ice thickness will brella of the recently established vidual investigator-driven interna- permit high-confidence borehole International Partnerships for Ice tional collaborations on WAIS Divide thermometry-based temperature Coring Science (IPICS), although its are highly encouraged, although no estimates for the past glacial pe- planning long predates IPICS. WAIS formal, top-down structure for col- riod. Other Antarctic borehole ther- Divide is one of the fi rst elements laboration has been imposed. mometry efforts have been stymied to get underway in the IPICS 40,000 by the low accumulation rate. WAIS Year Network, which will map spa- REFERENCES Divide should provide the fi rst reli- tial variation at the regional scale in Brook, E.J., White, J.W.C., Schilla, A.S.M., Bender, M.L., Barnett, B., Severinghaus, J.P., Taylor, K.C., able direct temperature estimate of order to better understand the dy- Alley, R.B., Steig, E.J., 2005: Timing of millennial- the last glacial maximum in Antarc- namics of the last deglaciation (see scale climate change at Siple Dome, West Ant- tica. Other borehole logging (optical, Brook, this issue). The importance arctica, during the last glacial period, Quaternary Science Reviews, 24: 1333-1343. sonic) will place unique constraints of spatial differences between cores Taylor, K.C., White, J.W.C. Severinghaus, J.P., Brook, on ice deformation, which combined within Antarctica has been high- E.J., Mayewski, P.A., Alley, R.B., Steig, E.J., Spen- with accurate surface temperature lighted recently by the Siple Dome cer, M.K., Meyerson, E., Meese, D.A., Lamorey, G.W., Grachev, A., Gow, A.J. and Barnett, B.A., history, timescale, and accumulation record (Taylor et al., 2004). Improved 2004: Abrupt climate change around 22 ka on the rate, will make a potent synergy for understanding of regional variations Siple Coast of Antarctica, Quat. Sci. Rev., 23: 7-15. glaciological modeling of the history in climate during the past 100 kyr Severinghaus, J.P., Grachev, A., Luz, B., and Caillon, N., A, 2003: method for precise measurement of of the WAIS. This effort will address will help separate global from re- argon 40/36 and krypton/argon ratios in trapped questions about the stability of this gional signals. air in polar ice with applications to past fi rn thick- marine-based ice sheet, which would International collaboration has ness and abrupt climate change in Greenland and at Siple Dome, Antarctica, Geochim. Cosmochim. raise sea level 5 m if melted. already greatly aided the DISC deep Acta, 67: 325-343. drill development, and it is antici- Wider perspectives of the WAIS pated that international partnerships project on WAIS Divide drilling and science International collaboration fi gures will continue at a heightened pace in prominently in the WAIS Divide ef- the context of the International Polar

International Trans Antarctic Scientiﬁ c Expedition (ITASE)

PAUL ANDREW MAYEWSKI Climate Change Institute, University of Maine, Orono, USA; [email protected]

Introduction ITASE has as its primary aim the collection and interpretation of a continent-wide array of environmental parameters (Fig. 1), assembled through the coordi- nated efforts of scientists from 20 nations. ITASE offers the ground- based opportunities of traditional style traverse travel, coupled with the modern technology of GPS, crevasse detecting radar, satellite communications and multi-disciplinary research (Fig. 2). By oper- ating predominantly in the mode of an oversnow traverse, ITASE offers scientists the opportunity to experience the dynamic range of the Antarctic environment. The combination of disciplines represented by ITASE provides a unique, multi-dimensional (x, y, Fig. 1: ITASE national traverse routes superimposed on RADARSAT image. Solid lines repre- z and time) view of the ice sheet sent completed traverses, dashed represent proposed or planned traverses. and its history. As of 2004, ITASE 7000 m), remotely penetrated Results has completed >20,000 km of to ~4000 m into the ice sheet, Although full-scale reconstruc- snow radar, recovered more than and sampled the atmosphere to tions of past climate over Ant- 240 firn/ice cores (total depth heights of >20 km. arctica have yet to be ﬁ nalized,

PAGES NEWS, VOL.14, N°1, APRIL 2006 Science Highlights: Ice Core Science 27

Ice topography Outlook Shallow radar coverage US-ITASE Core Site (70-100 m) Ice sheet Mass balance site (schematic) Field measurements including new Ice velocity vector (schematic) Deep radar internal techniques, e.g. Lidar and airborne Cartoon of 3D ice surface reflectors Summer air/snow temperature profile topography surveyed Site 01-3 Bedrock reflector Winter snow temperature profile for ice dynamics & 8.5 m/yr coherent GPR, laboratory ice ﬂ ow mass balance Site 01-1 1620 200 yrs 1830 studies, new computer modeling Ice Surface 1610 (from GPS) 1840 5 m/yr techniques, including new remote Shallow radar 200 yrs ice core & 1600 snow pit up 1810 sensing techniques, e.g. Satellite to 0.12 km Continuous shallow Elevation (m) 1590 Radar (SAR) interferometry, all 200x Vertical radar coverage to 1800 exaggeration 120 m depth between -4 -2 0 2 4 ice core sites -4 -2 0 2 4 contribute to ISMASS and ITASE Distance (km) Distance (km) Ice surface (from GPS) goals. The extensive use along 1000 ITASE traverses of new techniques

GPS-derived ice topography 0 like GPR and GPS, integrated with and deep radar interpretation 17,500 yr. Isochrone core data, provide detailed informa-

up to 3.2 km Elevation (m) -1000 dated from Byrd Deep Core (Blunier and Brook, 2001) Bedrock tion on surface mass balance. Some -2000 20x Vertical exaggeration GPR layers have been surveyed 200 300 400 A Distance (km) B extensively throughout Antarctica Fig. 2: Multi-dimensional approach to the multi-disciplinary ITASE objectives. Studies at a and they can be used as historical variety of spatial scales extending from the subglacial bedrock to the surface. Ice core sites along each traverse route produce 200-1000+ year annually dated climate records. Ice core benchmarks to study past accumu- site selection is determined by fi eld interpretation of shallow radar data. Numerous measure- lation rates. In addition, coupling ments are made at each core site to provide context for the ice core climate records. These ground survey data with satellite- measurements include: high-resolution surface topography maps; snow pit measurements of density, chemistry, stable isotopes, temperature; and meteorological data. Ice mass balance based observations provides new and horizontal velocity studies located 200 years upstream provide past ice fl ow history for the tools for measuring, for example, ice cores. Shallow and deep-penetrating radio echo sounding data tie the ice cores together and ice surface velocity and ice sheet provide large-scale context for ITASE cores and future deep ice core climate records. Internal stratigraphy in both radio echo sounding records represents isochronal events, and a record surface temperature. of depositional and ice fl ow history along the traverse. The radar data and interpretation, and The growing ITASE database ice topography along the radar profi les shown here are actual examples of the 2001 US-ITASE has the potential to explore tem- season. Figure by Brian Welch, St. Olaf College, US ITASE. poral variability and recent evolu- ITASE has pioneered calibration cused on understanding the fac- tion of Antarctic climate, utilizing tools, reconstruction of climate tors that control climate variability an unprecedented spatio-temporal indices, and evidence for climate over Antarctica and the Southern array. Data extraction and valida- forcing, using single-sites through Ocean. tion activities are an essential pre- to multiple arrays of sites. Initial Understanding the distribution liminary to the synthesis task. Such syntheses of combined ITASE and of snow precipitation over the Ant- activities, together with the devel- deep ice core records demonstrate arctic continent, and the surface opment of instrumental calibration that inclusion of instrumentally processes on different spatial and techniques, have been a signifi cant calibrated ITASE ice core records temporal scales that redistribute component of ITASE studies. Maps allows the previously unavailable this precipitation, is the area of of surface distribution of chemi- reconstruction of past regional greatest common interest be- cal species (Bertler et al., in press) to continental scale variability in tween ITASE and another SCAR indicate the unprecedented scope atmospheric circulation and tem- (Scientifi c Committee on Antarctic for exploring climate variability as perature. Emerging results dem- Research) activity, Ice Sheet Mass onstrate the utilization of ITASE Balance and Sea Level (ISMASS). Project facts records in comparisons with me- ITASE research reveals high vari- teorological reanalysis products. ability in surface mass balance and Project: ITASE Contact: Paul Mayewski, Connections are now noted be- the fact that single cores, stakes, [email protected] tween ITASE climate proxies and and snowpits do not represent the Participants: Scientifi c and logistics global scale climate indices such geographical and environmental institutions from 20 nations: Argentina, as ENSO, in addition to major characteristics of a local region. Australia, Belgium, Brazil, Canada, Chile, atmospheric circulation features Field observations show that the China, France, Germany, India, Italy, Japan, over the Southern Hemisphere, interaction of surface wind and The Netherlands, New Zealand, Norway, Russia, South Korea, Sweden, UK, USA. such as the Amundsen Sea Low, subtle variations of surface slope Funding: National contributions East Antarctic High, and Antarctic have a considerable impact on Where: Antarctica Oscillation. Large-scale calibra- the spatial distribution of snow at When: Endorsed by the Scientifi c Committee tions between satellite-deduced short and long spatial scales. Data on Antarctic Research (SCAR). surface temperature and ITASE ice collected in the ITASE framework Activities since 1992 and ongoing. core proxies for temperature are and by associated projects (EPICA What: Snow pits, shallow and intermediate also now available. ITASE is also DC and DML, Siple Dome, Law ice cores covering decades to millennia, developing proxies for sea ice, a Dome, Dome Fuji) also reveals multiparameter analysis Web page: www.ume.maine.edu/itase/ critical component in the climate systematic biases compared to system. ITASE research is also fo- previous compilations.

PAGES NEWS, VOL.14, N°1, APRIL 2006 28 Science Highlights: Ice Core Science

Mayewski, P.A. and Goodwin, I., 1997: ITASE Science extended time-series become avail- past climate conditions with near- and Implementation Plan, Joint PAGES/GLOCANT able over broad regions through instrumental quality. Report. PAGESPAGES IPO, Bern - Switzerland ITASE and deep drilling projects. Mayewski, P.A., Frezzotti, M., Bertler, N., van Ommen, The Antarctic-wide comparison of NOTE: T., Hamilton, G.H., Jacka, J., Welch, B., Frey, M., This article was abstracted from Mayewski Dahe, Q., Ren, J., Simoes, J., Fily, M., Oerter, H., glaciochemical records provides a Nishio, F., Iasaksson, E., Mulvaney, R., Holmund, P., et al., in press. This paper summarizes Lipenkov, V. and Goodwin, I., in press: The Interna- unique opportunity to achieve an ITASE accomplishments with references. tional Trans-Antarctic Scientiﬁ c Expedition (ITASE) For details concerning national programs, understanding of the fundamental – An Overview, Annals of Glaciology. factors that ultimately control the the ITASE Science and Implementation Plan (Mayewski and Goodwin, 1997), and other chemistry of a snow or ice sample. ITASE information refer to the SCAR Project The ability to determine individual Office maintained at the Climate Change sources and pathways of aerosols, Institute, University of Maine (www.ume. as well as mechanisms that rule maine.edu/itase/). precipitation efﬁ ciency and post- depositional effects, will allow the REFERENCES exceptionally detailed and accurate Bertler, N., Mayewski, P.A., Aristarain, A. and 46 others, in press: Snow chemistry across Antarc- interpretation of glaciochemical re- tica, Annals of Glaciology. cords necessary for reconstructing

A new 3000 m deep ice core drilled at Dome Fuji, Antarctica

YOSHIYUKI FUJII National Institute of Polar Research, Tokyo, Japan; [email protected] Introduction On 23 January 2006, the Japanese Antarctic Research Expedition (JARE) succeeded in drilling a 3029 m deep ice core at Dome Fuji in East Antarctica (77°19’01”S, 39°42’12”E, 3810 m asl; Fig. 1). Dome Fuji is the third place where a more than 3000 m deep ice core was collected in Antarctica, after Vostok (3623 m in Fig. 1: A bird’s eye view of the Antarctic ice sheet. Dome Fuji is located at the summit of Dronning Maud Land. This is the ideal place for ice core climate research because no horizontal depth, January 1998) and Dome C ice fl ow movements occur. (3270 m in depth, December 2004). The drilling will be continued next 2001/2002 season, and in Decem- chips from flowing out into the season in order to hit bedrock, ber 2003, drilling was resumed 40 borehole when the drill is being which is estimated to be located m away from the first borehole. winched up. The average drilling 3030±15 m below the surface. This time, we utilized a newly de- depth was 3.7 m/run and the speed A previous deep ice core, of veloped, highly effi cient drill, us- was 178 m/week until it got down 2503 m length, was drilled at Dome ing a pipe with small holes 2 mm to 3000 m depth. This is the fastest Fuji in December 1996, tracing back in diameter at intervals of 7 mm to performance ever in deep ice core to past 340 ka. The high resolution act as a chip chamber to store ice- drilling in the Antarctica and Green- stable isotope record (δ18O) showed cutting chips. We also developed land. Figure 2 shows a scene of the an extraordinary coherence (Wata- a bulb which prevents ice-cutting deep ice core drilling at Dome Fuji. nabe et al., 2003) with the deep ice Around 3000 m depth, the drill- core from Vostok (Petit et al., 1999), ing speed decreased sharply as which also reaches as far back in the drill hit “warm ice”. We took time but is located 1500 km away measures against this warm ice, from Dome Fuji. This fact strongly referring to the reports of deep ice supports a homogeneous climate coring at Dome C, NGRIP and oth- development over the last 340,000 ers. We changed the shape of the years on the high plateau of East drill cutter and the shape of the Antarctica. mount so that they would not easily get frozen and also coated the cut- Drilling of the new ice core ter with Tefl on. However, freezing of During the 1996 drilling, the drill “water” still made drilling diffi cult got stuck in the borehole and was and we could drill only about 0.5 m Fig. 2: Deep ice core drilling at Dome Fuji not able to be recovered. A new using a newly developed drill with highly effi - each run. drilling site was constructed in the cient performance.

PAGES NEWS, VOL.14, N°1, APRIL 2006 Science Highlights: Ice Core Science 29

analyses at the National Institute of Polar Research, Hokkaido Uni- versity, and other institutions in Japan. Our main research objectives are 1) To reconstruct the global climate and environmental changes that occurred during the past 800 ka to 1 million years. 2) To determine the impacts of the geomagnetic fi eld reversal on the global climate and the environment around 780 ka BP. 3) To clarify the relationship be- Fig. 2: A tephra layer in a half-cut ice core sample. There are a few tephra layers that were not tween the paleo-solar activity found in the previous 2503 m deep ice core from Dome Fuji. and the global climate. Properties of the ice core tephra layers (Fig. 3) that were not 4) To clarify the relationship be- In situ ECM (Electric Conductivity observed in the fi rst 2503 m deep tween biological evolution of Measurement) and optical strati- ice core. the ice core microbes and en- graphic observations will be per- vironmental changes. formed at Dome Fuji. The detailed Outlook Furthermore, if we can obtain analysis will be conducted in Ja- One half of the ice core will be kept samples of the bedrock, it may be pan, and we expect to determine in a storage trench at Dome Fuji possible to get information on the the approximate age of the core and the other half will be brought formative period of the Antarctic by detecting glacial cycles and back to Japan by our Antarctic re- ice sheet in the Tertiary. signals of the Brunhes-Matuyama search vessel in April. These ice magnetic reversal at around 780 cores will be used for various REFERENCES ka, and by using a glaciological Watanabe, O., Jouzel, J., Johnsen, S., Parrenin, F., Shoji, H., and Yoshida, N., 2003: Homogeneous flow-model. It is difficult to say Project facts climate variability across East Antarctica over the at present but we expect that the past three glacial cycles, Nature, 422: 509-512. core may be 800 ka old, as is the Project: Dome Fuji Ice Core Petit, J. R., Jouzel, J., Raynaud, D., Barkov, N.I., Barnola, Contact: Yoshiyuki Fujii, [email protected] J.-M., Basile, I., Bender, M., Chappellaz, J., Davis, case for the Dome C deep ice core, Participants: Numerous scientists from the M., Delaygue, G., Masson-Delmotte, V., Kotlyakov, or even older. This expected age is National Polar Institute, Tokyo, and several V.M., Legrand, M., Lipenkov, V.Y., Lorius, C., Pepin, suggested from the fact that the L., Ritz, C., Saltzman, E., and Stievenard M., 1999: Japanese Universities. Climate and atmospheric history of the past 420,000 geothermal heat fl ux in Dronning Funding: Japanese National Funding years from the Vostok ice core, Antarctica, Nature, Maud Land where Dome Fuji is Where: Eastern Dronning Maud Land, 399: 429-436. located is probably smaller than East Antarctica that of the eastern part of East Ant- When: 2004 ongoing arctica where Vostok and Dome C What: Deep ice cores to bedrock; Multi- parameter analysis are located. We discovered new

Vostok Ice Core project

VLADIMIR LIPENKOV1 ON BEHALF OF THE VOSTOK PROJECT MEMBERS 1Arctic and Antarctic Research Institute (AARI), St. Petersburg, Russia; [email protected] Introduction obtain a long climatic record with be separated into three distinct Over the last 25 years, the three relatively high time-resolution. In sections. The upper 3310 m of the deep ice cores 3G, 4G and 5G, January 1998, the collaborative core are characterized by an undis- drilled at the Russian Vostok Sta- project between Russia, France turbed sequence of ice layers. The tion (Fig.1), have provided a wealth and the United States to drill the analysis of this section of the core of information about past climate 5G hole at Vostok yielded the lon- resulted in the ﬁ rst record of Ant- and environmental changes. At gest ice core ever recovered, reach- arctic ice extending through four this site in East Antarctica, the ice ing a depth of 3623 m. The drilling climate cycles back to 420 kyr BP thickness is 3750 m and the snow stopped 130 m above Lake Vostok, (Petit et al., 1999). Between 3310 accumulation rate is only 2.1 cm a deep subglacial water body that and 3539 m, there are indications of water equivalent per year. This extends over a large area below of ice-ﬂ ow anomalies that could provides the unique opportunity to the ice sheet. The 5G ice core can have altered the original stratig-

PAGES NEWS, VOL.14, N°1, APRIL 2006 30 Science Highlights: Ice Core Science

et al., 2005). The records indicate that the climate on our planet during this time has always been in a state of change but with atmospheric and climate properties oscillating between stable bounds. Most of the climate variability during glacial- interglacial changes occurs with periodicities corresponding to that of the precession, obliquity and eccentricity of the Earth’s orbit, with a larger concentration of variance in the 100-kyr band. The overall amplitude of the glacial-interglacial temperature change is 12°C at the ice-sheet surface, as judged from the Vostok isotope record. Fig. 1: Drill units at the Russian Vostok Station in East Antarctica. The “sawtooth” pattern of the raphy of glacial ice. Finally, below coverage of marine isotope stage Vostok isotopic temperature record 3539 m, the core consists of ice re- (MIS) 11 (Raynaud et al., 2005). roughly mimics the sea level (refrozen from lake water. Using an versed global ice volume) changes appropriate correction of the ice The 440 kyr climatic record deduced from marine sediment stratigraphy for ﬂ ow disturbance from the Vostok ice core studies. The much higher dust con- in the 3320-3345 m interval, it has Figure 2 shows a series of selected centration during full glacial periods recently been possible to extend Vostok records covering the last 440 than during interglacials is interpret- the Vostok ice record farther back kyr (adopted from Petit et al., 1999; ed as indicating more extensive des- to 440 kyr BP, which implies full Delmotte et al., 2004 and Raynaud erts and continental areas (low sea

0.5

-420 1 Dust (p.p.m.) ) -440 1.5

D (‰ -460 δ

-480 280

240 (p.p.m.v.)

200 2 700 CO 160 600

(p.p.b.v.) 500 4

CH 400

0 )

-50 3 5 5 9. 7. 5.

11.3 -100 Sea level (m level Sea 400 300 200 100 0 Age (kyr BP)

Fig. 2: Vostok time series and sea level derived by calibrating the marine δ18O record (Bassinot et al., 1994). The dust record provides information on aerosols of continental origin. The deuterium content of the ice δD is taken as a proxy for Antarctic temperature; the warmest periods of the past correspond to MIS 5.5, 7.5, 9.3 and 11.3. The atmospheric concentrations of the two greenhouse gases (CO2 and CH4) are measured on the air enclosed in the ice. The rapid anthropogenic rise in concentrations of CO2 and CH4 since the 1850’s,1850’s, up to present-daypresent-day levelslevels of 360 ppmv and 1750 ppbv, respectively, are indicated by arrows. The Vostok data (Petit et al., 1999; Delmotte et al., 2004; Raynaud et al., 2005) are plotted on the EDC2 timescale after Raynaud et al., 2005.

PAGES NEWS, VOL.14, N°1, APRIL 2006 Science Highlights: Ice Core Science 31

level), more intense surface winds that the joint effort of scientists work- in the source regions, and/or more Project facts ing in the fi elds of paleoclimate re- effi cient meridional transport at the Project: Vostok ice core project cords and physical properties of ice times of glacial maxima (Petit et al., Contact: Vladimir Lipenkov, will allow us to decipher information 1999). The close linkage between cli- [email protected] on some of the earlier climatic cycles mate and CO2 and CH4 concentra- Participants: Institutes and laboratories archived in this section of the Vostok tions documented in the Vostok core in Russia (AARI of Roshydromet; St. core. Meanwhile, comprehensive throughout the four climatic cycles Petersburg Mining Institute; Institute of analysis of the now available accre- Microbiology, RAS; Kazan State University; supports the role of the greenhouse tion ice from depths below 3539 m is Institute of Geography, RAS), in France gases as amplifi ers of initial orbital (LGGE, CNRS, Université Joseph Fourier, expected to provide a clue to under- forcing. Grenoble; Laboratoire des Sciences du standing the extraordinary environ- The sequence of events during Climat et de l’Environnement, CNRS-CEA, ment of subglacial Lake Vostok. glacial terminations suggests that Saclay) and in the United States (laboratories funded by NSF). increases in Antarctic air tempera- REFERENCES Funding: The Vostok venture was made ture and atmospheric greenhouse Caillon, N., Severinghaus, J., Jouzel, J., Barnola, possible by the logistical support of Rus- J.M., Kang, J. and Lipenkov, V.Ya., 2003: Timing gas concentrations lead sea level sian Antarctic Expedition (RAE), Institute of Atmospheric CO2 and Antarctic temperature rise (Northern Hemisphere de- Francais pour la Recherche et la Tech- changes across Termination III. Science, 299: glaciation) by a few thousands of nologie Polaires (IFRTP) and the Offi ce of 1728-1731. Masson-Delmotte, V., Chappellaz, J., Brook, E., years (Petit, et al., 1999, Sowers et Polar Programs (NSF). The development of drilling technology and the ice-core studies Yiou, P., Barnola, J.M., Goujon, C., Raynaud, D. al., 1991, Shackleton, 2000). It has were funded by national contributions from and Lipenkov, V.Ya., 2004: Atmospheric methane also been shown that CH (Delmo- during the last four glacial-interglacial cycles: 4 Russia, France and the United States. Rapid changes and their link with Antarctic tte et al., 2004) and CO2 (Caillon et Where: East Antarctica (78°28’S, 106°48’E, temperature. J. Geophys. Res., 109: D12104, doi: al., 2003; Fischer et al., 1999; Petit, altitude 3488 m asl, ice thickness 3750 m) 10.1029/2003JD004417. et al., 1999; Pépin, et al., 2001) con- When: 3 main deep holes (3G, 4G, 5G) were Fischer, H., Wahlen, M., Smith, J., Mastroianni, D. centration increases lagged Antarc- drilled from 1980 to 1998. The ice core and Deck, B., 1999: Ice core records of atmo- analyses are in progress. spheric CO2 around the last three glacial termina- tic warming by several hundreds What: 3 ice cores reaching depths of 2202 tions, Science, 283: 1712-1714. of years. This natural scenario is, m, 2546 m and 3623 m. High-resolution Petit, J. R., Jouzel, J., Raynaud, D., Barkov, N.I., Barnola, however, different from the present J.-M., Basile, I., Bender, M., Chappellaz, J., Davis, records of atmospheric composition and M., Delaygue, G., Masson-Delmotte, V., Kotlyakov, situation, where rise of greenhouse climate covering the last 440 kyr. V.M., Legrand, M., Lipenkov, V.Y., Lorius, C., Pepin, gases, as a result of anthropogenic Database: www.ncdc.noaa.gov/paleo/ L., Ritz, C., Saltzman, E., and Stievenard M., 1999: activities, has been imposed fi rst. icecore/antarctica/vostok/vostok.html Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica, Nature, The reconstructed record for MIS 399: 429-436. 11 indicates that concentrations of Raynaud, D., Barnola, J.M., Souchez, R., Lorrain, R., CO and CH throughout this 30-kyr- Ongoing ice core studies Petit, J.R., Duval, P. and Lipenkov, V.Ya., 2005: The 2 4 record for marine isotopic stage 11. Nature, 436: long interglacial period, which is Studies of the Vostok ice are now 39-40. considered an “orbital” analog for focused on the deepest section of Salamatin, A.N., Tsyganova, E.A., Lipenkov, V.Ya. the Holocene, were close to the pre- the core, below 3310 m. The extrap- and Petit, J.R., 2004: Vostok (Antarctica) ice-core time-scale from datings of different origins. Ann. industrial levels and lower than dur- olation of the Vostok timescale to Glaciol., 39: 283-292. ing MIS 9.3 (Raynaud et al., 2005). greater depths, made with the aid of Thus, the present-day increase in an ice-sheet fl ow model, shows that For full references please consult: concentration of these greenhouse the age of glacial ice just above its www.pages-igbp.org/products/newsletters/ref2006_1.html gases in the Earth’s atmosphere contact with accretion lake ice (at a seems to have been unprecedented depth of 3530 m) may reach ~2000 during the past 440 kyr. kyr (Salamatin et al., 2004). We hope

European Project for Ice Coring in Antarctica (EPICA)

ERIC WOLFF1 ON BEHALF OF THE EPICA COMMUNITY 1British Antarctic Survey, Cambridge, UK; [email protected]

Introduction the atmosphere. By learning about recorded in the same core. In early The last few hundred thousand these changes, we can understand Antarctic cores covering complete years form the context in which the processes that can occur, and glacial-interglacial cycles (notably we can learn how the Earth Sys- that should be represented by mod- Vostok and Dome Fuji), we were tem (including its climate) works. els—the same models that will be able to see the close connection Although the geological setting used to predict future conditions. between climate and greenhouse of the Earth was similar to today, Ice cores are particularly pow- gas concentrations that prevailed very signiﬁ cant changes occurred erful because numerous climate through four glacial-interglacial in the climate, the circulation of responses and forcings (including cycles over the last 400 kyr (Petit the ocean, and the composition of greenhouse gas concentrations) are et al., 1999, Watanabe et al., 2003).

PAGES NEWS, VOL.14, N°1, APRIL 2006 32 Science Highlights: Ice Core Science

One other early focus of the Dome C core was MIS11. This period is often seen as an analog for the present and near future (in the absence of anthropogenic influence) because the orbital forcing of climate is similar in the two periods (with low eccentricity and hence weak precessional forcing). Although we can discuss how to align the climate records from the two periods, it is true that MIS11 was a very long interglacial: 28 kyr, using a deﬁ nition that makes the Holocene 12 kyr old so far. If this is a better analog than more recent short interglacials, then the “natural” Holocene would still have a long course to run.

Fig. 1: Dome C drilling location on the East Antarctic Ice Sheet (75°06’S, 123°21’E, altitude The Atlantic sector of the 3233 m asl) as viewed from the air (Photo Borek Air, PNRA/EPICA). Southern Ocean The current snow accumulation Greenland ice cores (e.g. North The bottom of the data published rate is 2-3 times higher in DML Greenland Ice Core Project Mem- so far (EPICA Community Mem- than at Dome C and, consequently, bers, 2004) most clearly revealed bers, 2004) is at about 740 kyr BP, the last climatic cycle is found at the importance of abrupt climate in the cold marine isotope stage much better resolution there. An- changes, probably resulting from (MIS) 18.4, although we are conﬁ - nual layers can still be observed changes in ocean heat transport, dent that we have a good climate even in the glacial ice, and the dif- during the last climatic cycle. record back as far as 800 kyr BP ference between the age of the ice The aim of EPICA was to drill (MIS 20.2). (containing the climate record) and two cores to bedrock in East Antarc- The ice core record now extends that of the air bubbles (containing tica. At Dome C, the target was old through eight glacial cycles and is the greenhouse gas record) is rela- ice; in Dronning Maud Land (DML), dominated by the 100 kyr cyclicity tively small. This should allow us to the aim was to obtain a South At- characteristic of the late Quaternary link the Antarctic records with the lantic counterpart to the high-reso- period. This is seen both in the tem- sequence of rapid climate changes lution Greenland records, covering perature proxy (deuterium), and in (Dansgaard-Oeschger (D-O) events) at least one climatic cycle. The drill- physical and chemical measure- seen in Greenland cores, with only ing at Dome C (Fig. 1) is complete ments (such as dust and sea salt) a small time uncertainty. It already and the ice contains a record of 800 that represent different aspects of appears that every D-O event found kyr of climate. At the time of writ- the environment (Fig. 2). However, in Greenland has a counterpart in ing, the drilling at DML was very the “pre-Vostok” cycles are dis- the Antarctic records, and learning close to the bed, and contained tinctly different from the later ones. about the relative phase and ampli- one climatic cycle at high resolu- Interglacials have a much lower tude of the Greenland and Antarctic tion and probably several more at amplitude before about 450 kyr BP events will be critical in distinguish- lower resolution. but appear to span a longer period ing between mechanisms and in in each cycle. This characteristic is testing models. The differences Eight glacial cycles in an also apparent in marine records but in response across the continent ice core is more pronounced in the ice core of Antarctica will also be of great The records from Dome C show that record. There is no obvious exter- interest, since although the deute- the top 2770 m of ice correspond nal forcing responsible for such a rium (temperature) records have to the “Vostok” time period and change, however many of the inter- great similarities at Dome C and nearly 500 m of older ice is below nal feedbacks in the system reﬂ ect DML, there are big differences in

that. The initial timescale (EDC2) it. For example, both CO2 (Siegent- the magnitude of concentrations of

for Dome C was obtained using haler et al., 2005) and CH4 (Spahni chemical species at the two sites. an ice ﬂ ow model constrained by et al., 2005) are at lower concentra- a small number of control ages. tions in the early interglacials. The Continuing analysis

There are obvious similarities and close correspondence between CO2 While the EPICA drilling opera- differences between the resulting and Antarctic temperature persists tions are essentially complete, climate record and marine records. throughout the record. much remains to be done in

PAGES NEWS, VOL.14, N°1, APRIL 2006 Science Highlights: Ice Core Science 33

2.0 Project facts 18 δ OSW stack Project: European Project for Ice Coring in ] 3.0

°° Antarctica (EPICA) / ° [ Contact: Eric Wolff, [email protected]

SW Participants: Numerous scientists from

O 4.0 laboratories in 10 European nations, under 18 -350 δ the auspices of the European Science MIS 5.5 Foundation (ESF) and European Union (EU). MIS11.3 5.0 EPICA Dome C -380 Funding: Funded by the EU (EPICA-MIS) and

] by national contributions from Belgium,

°° Denmark, France, Germany, Italy, The -410 Netherlands, Norway, Sweden, Switzer-

D [°/ land, and the U.K. The science was made δ 320 -440 possible only by the efforts particularly of the French (IPEV) and Italian (PNRA) Vostok logistic agencies for Dome C, the Alfred 280 EPICA Dome C -470 Wegener Institute in Germany for DML, and the drilling teams led by Laurent 240 Augustin (Dome C) and Frank Wilhelms (DML). [ppmv] 2 Where: East Antarctic Ice Sheet (Dome C:

CO 200 900 75°06’S, 123°21’E, altitude 3233 m asl, ice thickness ~3270 m; DML: 75°00’S, 160 750 0°04’E, altitude 2892 m asl, ice thickness Vostok EPICA Dome C ~2780 m). When: Drilling: 1996-2006 (survey work pre- 600 dates this and analysis continues). [ppbv] 4 What: 2 deep ice cores to bedrock, multi-

2000 450 CH parameter analysis Web Page: www.esf.org/esf_article. php?activity=1&article=85&domain=3 1500 300 Databases: www.pangaea.de/Projects/EPICA/ EPICA Dome C www.ncdc.noaa.gov/paleo/icecore/antarc- 1000 tica/domec/domec_epica_data.html

500 M., Delaygue, G., Masson-Delmotte, V., Kotlyakov, dust mass [ppb] V.M., Legrand, M., Lipenkov, V.Y., Lorius, C., Pepin, 0 L., Ritz, C., Saltzman, E., and Stievenard M., 1999: Climate and atmospheric history of the past 420,000 0 200 400 600 800 years from the Vostok ice core, Antarctica, Nature, age [kyr before present] 399: 429-436. Siegenthaler, U., Stocker, T. F., Monnin, E., Luthi, D., Schwander, J., Stauffer, B., Raynaud, D., Barnola, J. M., Fischer, H., Masson-Delmotte, V. and Jouzel, Fig. 2: Ice core parameters over 740 kyr, along with the recently compiled benthic marine J., 2005: Stable carbon cycle-climate relation- oxygen isotope record (Lisiecki & Raymo, 2005). The Dome C δD and dust data are on the EDC2 ship during the late Pleistocene. Science, 310: timescale (EPICA Community Members, 2004) and the marine data on the LR04 timescale. 1313-1317. CO and CH datadata are from Dome C (Siegenthaler et al., 2005;2005; Spahni et al., 2005)2005) and VostokVostok 2 4 Spahni, R., Chappellaz, J., Stocker, T. F., Loulergue, (Petit et al., 1999). MIS 5.5 and 11.3 are marked to provide reference points. L., Hausammann, G., Kawamura, K., Fluckiger, J., Schwander, J., Raynaud, D., Masson-Delmotte, V. analysis and interpretation of the work will help us to elucidate the and Jouzel, J., 2005: Atmospheric methane and cores. EPICA has given us the underlying mechanisms govern- nitrous oxide of the late Pleistocene from Antarctic ice cores. Science, 310: 1317-1321. ﬁ rst glimpse of an earlier period ing the highly variable behavior Watanabe, O., Jouzel, J., Johnsen, S., Parrenin, F. of Earth history, and the chance to of the Earth System. Shoji, H. and Yoshida, N., 2003: Homogeneous compare behavior across the vast climate variability across East Antarctica over the past three glacial cycles, Nature, 422: 509-512. continent of Antarctica through- REFERENCES out a glacial cycle. Intensive work EPICA Community Members, 2004: Eight glacial cycles from an Antarctic ice core. Nature, 429: is now underway to provide the 623-628. extended record from Dome C Lisiecki, L. E. and Raymo, M. E., 2005: A Pliocene- and the high-resolution record Pleistocene stack of 57 globally distributed benthic delta O-18 records. Paleoceanography, 20: PA1003; from DML. We will use additional doi:10.1029/2004PA001071. parameters, such as particulate North Greenland Ice Core Project Members, 2004: and dissolved aerosol species in High-resolution record of Northern Hemisphere climate extending into the last interglacial period. the ice, to deﬁ ne the climate, and Nature, 431: 147-151. use the detail of the two records Petit, J. R., Jouzel, J., Raynaud, D., Barkov, N.I., Barnola, to understand variability. Further J.-M., Basile, I., Bender, M., Chappellaz, J., Davis,

PAGES NEWS, VOL.14, N°1, APRIL 2006 34 Science Highlights

A 425-year precipitation history from documentary weather anomalies and climate records at Palermo, Italy

NAZZARENO DIODATO Monte Pino Research Observatory on Climate and Landscape, GTOS/TEMS, Benevento, Italy; [email protected]

For southern Europe, especially mediterranean Italy, our knowledge of environmental and climatic variations has until now been discontinuous or founded on very few multisecu- lar precipitation series (Cantù and Narducci, 1967; Brunetti et al., 2004). Fortunately, the Italian area offers a wide range of descriptive documentary data (i.e., reports from chronicles, daily weather reports, religious ceremonies, local books, etc.), that makes this area ideal for climate reconstructions on various time and spatial scales prior to the instrumental period (Enzi and Camuffo, 1996; Diodato, 1999; Luterbacher et al., 2005). The pre-instrumental epoch includes the so-called Little Ice Age (LIA), variously assessed as AD 1300-1900, that is not expected to be homogeneous and sustained over large climatic regions (Bradley and Jones, 1993). So, climatic research at regional and sub-regional scales for the pre-instrumental epoch is use- Fig. 1: Geographic location (a); map of the Lang Index (b) with PalermoPalermo ProvinceProvince (white square ful for understanding the nature of box) and Palermo Observatory (white circle). climate variability on multi-decadal ture and living conditions have been summer, PI was halved for June, and longer timescales. In the last taken as a proxy for instrumental ob- July and August (PI = 0); intensive decades, several studies have re- servations of the relative wetness and and/or continuous rains (PI = +1); ported climate reconstructions in dryness. Data were compiled from rains with fl oods (PI = +2). When the some European localities based on various kinds of documents, includ- authors did not comment on the me- documentary sources (for a synthesis ing chronicles (Moio and Susanna, teorological conditions, the situation see Brádzil et al., 2004). This research 1500-1769), annals (Corradi, 1865-94), was considered as ‘normal’ and was suggests that pre-instrumental docu- archival records (Piervitali and Colac- assigned the index PI = 0. Rodrigo’s mentary indices are promising tools ino, 2001) and two databanks of the indices were modifi ed to weighted for the reconstruction of rainfall and SICI-CNR Project (available online at seasonal indices by minimizing the thermal regime fl uctuation. In this http://sici.irpi.cnr.it/giano.htm), refer- sum squared errors (SSE) between way, precipitation history for south- ring mainly to Palermo Province (Fig. the Annual Rainfall Anomalies (ARA) ern Europe during the period 1580- 1b). As a consequence, a numerical and Precipitation Index Sum (PIS) in 2004 AD was analyzed at the Palermo index was established to characterize the calibration period - overlapping Astronomical Observatory (Sicily, the rainfall regime and its evolution. indexed and measured precipitation Italy; Fig. 1a). The compilation of the data is based records (1839-1868) - as: on the method introduced by Pfi ster N 2 Data and methods (1988). However, in this work, due to SSE = ∑(ARA j− PISj ) The Sicily region is characterized the regional climate peculiarities, the j=1 by a typical Mediterranean regime, weather anomalies related to rainfall with very dry summers and moist were coded following the modifi ed where PIS is the sum of the monthly cold seasons (Autumn-Winter) when classifi cation of Rodrigo et al. (1998): index for each year, j. Using the PIS most precipitation occurs. Climate in meteorological drought from Octo- index as the independent variable Palermo Province is represented by ber to April (Precipitation Index, PI = and measured annual rainfall anom- both steppe-lake and semi-arid zones –1); meteorological droughts in May alies as the dependent variable, a (Fig. 1b). Historical written records of or September (PI = –0.5); since pre- determination coeffi cient value, r2 weather conditions that affect agricul- cipitation is almost zero during the = 0.64 (statistically signifi cant at the

PAGES NEWS, VOL.14, N°1, APRIL 2006 Science Highlights 35

95% confidence level by a t-test), derived from the following linear equation: EPA = (19.41 + 50.76 · PIS); where EPA is the Estimated Precipita- tion Anomalies (mm), corresponding to the estimated value of total annual rainfall anomalies. Finally, annual reconstructed precipitation (RP) were computed following Fritts et al. (1979) by multiplying each value by the empirical standard deviation of instrumental data (SDMPA), and dividing it by the empirical standard deviation of estimations (SDEPA), as: RP = (EPA · (SDMPA / SDEPA) + PM); where the standard deviation ratio is equal to 1.35 and PM is the precipitation mean (mm) estimates over the calibration period. The non-parametric Thom test Fig. 2: Historical precipitation series (1580-2004) at Palermo Astronomical Observatory (a) grey (Thom, 1966) was also performed, re- line: precipitation reconstructed; black line: instrumental data from 1806 onwards; horizontal red line: mean value; dashed lines: threshold corresponding to 10th and 90th percentiles. sulting in a homogeneous series. Standardized Cumulative Anomalies (SCA) (b) withwith changeschanges inin 1677,1677, 1700,1700, 17691769 andand 19221922 inin the precipitation series. Results some particular contrasts in each of years that again show rainfall peaks The fi nal result of the precipitation sub-time series. Thus, SCA indicates that could increase the environmen- reconstruction is shown in Figure 2a, a change in the slope of the curve in tal risk connected with the sensitive allowing a preliminary view of tem- the years 1677, 1700, 1769 and 1922 landscape. poral evolution of annual RP from AD. The length of these periods re- More information about Global 1807 onwards, where instrumental veals no regular pattern. Notable was Terrestrial Observing System/Ter- data (Micela et al., 2001) began. That the wet period between 1677-1700 restrial Ecosystem Monitoring Sites is, after several years of high climatic that appears to be within the Maun- (GTOS/TEMS) can be found at: www. variability (from 1660 to 1930) during der Minimum (1675-1715 AD), indi- fao.org/gtos/tems/index.jsp the fi rst three centuries of the series, cating that solar activity is likely an a period of lower climatic variabil- important forcing of climatic change ACKNOWLEDGEMENTS ity followed (from 1940 to 2000). in the study region, in according with Thanks to Dr. Vincenzo Iuliano (Palermo – Astronomical Observatory, University of In particular, the 18th century was fi ndings from Greece (Xoplaki et al., Study) who facilitated the data collection on punctuated with alternating extreme 2001) and Spain (Barriendos, 1997). the precipitation series. drought and wet periods (including The longer and last wet phase is re- frequent fl oods), which exceeded the corded between 1769 and 1922 AD. REFERENCES 10th and 90th percentiles, respec- Bradley, R.S. and Jones, P.D., 1993: Little Ice Age summer temperature variations: their nature and tively. In order to identify possible Conclusions relevance to recent global warming trend. The climatic change, Standardized Cu- Longer timescale series are important Holocene, 3: 367-376. mulative Anomalies (SCA) was also to understanding climatic variations Brádzil, R., Pfi ster, C., Wanner, H., Von Storch, H. and Luterbacher, J., 2004: Historical climatology in computed after Mächel et al. (1998) on multi-decadal and centennial tim- Europe – the state of the art. Climatic Change, 70: and Jacobeit et al. (2001). Thus, sus- escales. In this paper, documentary 363-430. tainably declining/rising values in sources were an important proxy in a Brunetti, M., Maugeri, M., Monti, F. and Teresa, N., 2004: Changes in daily precipitation frequency and cumulative anomalies indicate the fi rst and preliminary investigation of distribution in Italy over the last 120 years. Journal prevalence of negative/positive an- precipitation fl uctuation for an Italian of Geophysical Research, 109: D05102, doi:10.1029/ nual anomalies, and major turning island of the Central Mediterranean 2003JD004296. points in cumulative anomalies in- (Sicily). Over the last 5 centuries, Jacobeit, J., Jönsson, P., Bärring, L., Beck, C. and Ekström, M., 2001: Zonal indices for Europe 1780- dicate transitions between periods different climatic epochs have alter- 1995 and running correlations with temperature. predominated by contrasting annu- nated with the respective transitions Climatic Change, 48: 219-241. al anomalies. However, this method periods: the Little Ice Age and the Rodrigo, F.S., Esteban-Parra, M.J. and Castro-Diez, Y., 1998: On the use of the Jesuit private correspon- does not identify the character of the Present-Day Warming with transition dence records in climate reconstructions: a case change or the stability of the series sub-periods. The last period of the study from Castille (Spain) for 1634-1648 A.D. before and after the change point, so 20th century rainfall series shows a Climatic Change, 40: 625-645. the results should be considered cau- behavior dissimilar to those of other For full references please consult: tiously. Figure 2b illustrates the SCA periods in the past, with a reduction www.pages-igbp.org/products/newsletters/ref2006_1.html series. It reveals notable and marked of the climate variability and a strong differences between the periods be- decrease of precipitation amount. fore and after the 20th century, with This is in contrast to very recent

PAGES NEWS, VOL.14, N°1, APRIL 2006 36 Science Highlights

Paleo sea-level changes in the Black Caspian Seas: Links to river runoff and global climate change

ALEXANDER KISLOV AND PAVEL TOROPOV Dept. of Meteorology and Climatology, Faculty of Geography, Moscow State University, Russia; [email protected], [email protected]

Introduction perturbations was several meters To assess the link between climate (Varushenko et al, 1987). variability and hydrological regime, we focused our study on the mid-Ho- The LGM locene (6 ka years BP) and the last The time slice at 21 ka BP, as an ex- cold period of the Late Quaternary (21 ample of the last glacial maximum ka BP). We discuss how well current (LGM), involves large changes in the �� general circulation models (GCMs) surface boundary conditions: ice can reproduce river runoff changes sheet extent and height, changes and, consequently, variations in in SSTs, albedo, sea level and con- closed lake level under contrasting centration of greenhouse gases and climate conditions. The Paleoclimate aerosols, but only minor changes in Modeling Intercomparison Project solar radiation at the top of the at- (PMIP) (Joussaume and Taylor, 1995) � �� mosphere. Here we look at the re- has run simulations that are used in sults of calculation of annual river this study. The rivers of the East Eu- Fig.1: Area of the Caspian Sea during the mid- runoff volumes for the Caspian and Holocene/modern (blue color) and regression ropean Plane (EEP) were selected for stage of the LGM evaluated based on the Black Seas. The regions of the mod- analysis. Feed of rivers is determined PMIP1 data (purple color). ern Baltic Sea and Arctic seas were by the balance of precipitation and simulations of other climate regimes. strongly perturbed during the LGM, evaporation in the catchment, hence Validation can be done on the basis and are therefore not included in river runoff change responds imme- of comparison of modeled P-E with this study. diately to climate changes. It is im- data of standard hydrological obser- At 21 ka BP, the total river runoff portant that both precipitation and vation in river estuaries. The majority to the Caspian Sea (calculated by evaporation are calculated by a GCM. of models simulate runoff to the Bal- “successful” models) was substan- Moreover, on large planes, such as tic Sea well (Table 1), but only a few tially decreased (~50%) compared the EEP, GCM data much better re- models are capable of reproducing to today’s climate (see Table 3). The ﬂ ect the state of climate compared runoff to the Black Sea and the Cas- relative contribution of Volga River to areas with complex mosaic sur- pian Sea with good accuracy. runoff is 72%. These facts are in ac- face conditions. Additionally, large cordance with the observational amounts of paleoclimate data exist The mid-Holocene data (Varushenko et al, 1987). on the EEP for selected periods of The mid-Holocene study within PMIP the past. 1 focussed on the 6 ka BP climate. As Implications for sea level a ﬁ rst approximation, SSTs were pre- Information about river runoff Modern GCM runs scribed to be the same as today, the change also provides a useful guide

Prior to investigating river runoff CO2 concentration was similar to its for conclusions about the status of changes in the past, it is necessary to pre-industrial value of 280 ppm, and the Caspian Black Seas. According to be convinced that GCMs are capable vegetation and land-surface charac- the deﬁ nition of the water budget for of simulating the modern climate teristics were held constant. Climate closed lakes, the steady-state equa- state. It was shown that only large change is only influenced by the tion of the annual water budget is: river catchments (covered by about change of insolation forcing. 15 GCM cells with typical GCM hori- Calculations indicate that at 6 ka zontal resolution 2.5 x 2.5°) can be BP there is no signiﬁ cant change of correctly analyzed and analyzing the the EEP river runoff (see Table 2). smaller river basins is not meaning- The Volga River contribution to the ful. The runoff value is estimated in total volume of water running to the the framework of a GCM as the an- Caspian Sea slightly increases (93%) nual value P-E (precipitation minus compared to today’s climate (88% ac- �� evaporation). If the error of modeled cording to PMIP 1 model simulations runoff is ±20%, the result was consid- and 84% based on observation). In ered to be “successful” because in spite of the slight reaction of river � �� this case deviation does not exceed runoff to external orbital forcing, it Fig. 2: Area of the Black Sea during the mid- observed natural variability. The data is unexpected that the Caspian Sea Holocene/modern (blue color) and regression of these “successful” models were level was not stable during the Ho- stage of the LGM evaluated based on the examined more closely by running locene. The amplitude of sea-level PMIP1 data (purple color).

PAGES NEWS, VOL.14, N°1, APRIL 2006 Science Highlights 37

3 Table 1: Today’s annual volume of the EEP river runoff (km ) into differentdifferent ocean basins, cycle (precipitation, evaporation simulated by the PMIP1 GCMs. and runoff) for large rivers under � �� different climatic situations. The dif- �� ferences in hydrological mode of �� the rivers of the EEP between 6000 �� years BP and today are small. This �� fact corresponds to results of paleo- �� hydrological reconstructions and is �� particularly interesting from the point �� of view that the warm mid-Holocene �� is often considered to be an analog �� of expected future climate warming �� conditions. �� The results of modeling have �� shown that during the LGM, the run- �� off of the EEP rivers was consider- �� ably decreased (~50 %) and provided �� strong regression of the Caspian and 1�Relative error (%); 2ENS: Ensemble mean of GCMs data; 3SUCS: Ensemble mean of successful GCM data (selected in Black Seas. Comparing our modeling 4 Table 1); Obs: Mean of observational data results with geological evidence, we 21 ka BP, therefore the second term suppose that simulated conditions ef = YF (1) in the Eq. (3) is equal to zero. Value refl ect the so-called Atelskay regres- where F, f, e, and Y stand for the over the Caspian Sea was estimated sion stage of the Caspian Sea and the catchment area, lake area, differ- (based on regional climate model- so-called Postkarangatskay regres- ence (E-P) over the lake area, and ing (Kislov and Surkova, 1997)) to sion stage of the Black Sea (Varush- the river runoff from the catchment be small relative to the fi rst term in enko et al, 1987; Svitoch, 2003). This into the lake, respectively. Variation Eq. (2). Calculations indicate that a Table 3: Annual volume at 21 ka BP of the EEP of the lake area relative to the pres- decrease of the river runoff causes a river runoff (km3) into difdifferentferent ocean basins, ent status (denoted by index ‘0’) may substantial drop in the Caspian Sea simulated by the ensemble and the “success- be expressed by: level (~50 m) (see Fig. 1). The calcu- ful” PMIP1 models �� lated river runoff for the Black Sea is � ∆f ∆Y ∆F ∆e �� = + − (2) also substantially decreased (~50%) �� f Y F e �� 0 0 0 0 (see Table 3). This fact, coupled with �� It allows us to evaluate the contribu- the assumption that due to decreas- For� defi nitions, see Table 1; 1Relative deviation from today’s value (%) tion of different factors to change of ing sea level the Black Sea was a the level (h) as: closed lake at 21 ka BP, allows us to lends credit to the idea of the connec- estimate that the drop in level was tion between Late Quaternary glacial/ (3) ∆h = (∆h)Y + (∆h)F + (∆h)e approx. 200 m (Fig. 2). cooling/drying planetary events and It is supposed (based on geomorpho- deep regression states of the Caspian logical evidences) that the confi gu- Conclusions Sea and the Black Sea. ration of the catchment area of the GCMs are able to correctly repro- rivers was principally unchanged at duce elements of the hydrological ACKNOWLEDGMENTS This research was funded by the Russian Table 2: Annual volume at 6 ka BP of the EEP river runoff (km3) into the differentdifferent basins Fund for Basic Research. More information �� about PMIP is available at www-pcmdi.llnl. � � � � � � gov/pmip and www-lsce.cea.fr/pmip2. �� REFERENCES �� Joussaume, S. and Taylor, K., 1995: Status of the �� paleoclimate modeling intercomparison project �� (PMIP). Proc. First International AMIP Sci. Conf.: 425- �� 430. WCRP 92, WMO/TD 732, Geneva. �� Kislov, A.V., and Surkova, G.V., 1997: Simulation of the �� Caspian Sea level changes during the last 20000 �� years. In: Benito G., Beker V.R and Gregory K.J. (edi-

�� tors) - Palaeohydrology and environmental change: �� 235-244. John Wiley & Sons, Chichester. �� Svitoch, A.A., 2003: Marine Pleistocene of Russian �� seashore. GEOS, Moscow, 362p. (In Russian). �� Varushenko, S.I., Varushenko, A.N., Klige, R.C., 1987: �� Level changes of the Caspian Sea and closed lakes in �� the past. Nauka, Moscow, 255p. (In Russian). ��

For deﬁ nitions, see Table 1. 1Relative deviation from today’s value (%)

PAGES NEWS, VOL.14, N°1, APRIL 2006 38 Science Highlights

Quaternary climate change in south-eastern Arabia

FRANK PREUSSER1 AND DIRK RADIES2 1Institute of Geological Sciences, University of Bern, Switzerland; [email protected] 2Geological Institute, RWTH Aachen University, Germany; email; [email protected]

The present day climate over the south-eastern Arabian Peninsula is characterized by pronounced arid conditions. The aridity is due to the presence of the Intertropical Convergence Zone (ITCZ) over the southernmost part of the peninsula during summer, which prevents the movement of humid air masses north (Fig. 1a). Precipitation, resulting from moisture transported by southwesterly winds across the In- dian Ocean and towards the Tibetan Plateau (Summer Monsoon), is only recognized as coastal fog and seasonal rainfall in the southern part of Oman (Dohfar), without affecting other parts of the region. During the Fig. 1: The present low-level circulation pattern over the Arabian Peninsula during (a) summer and (b) wwinter,inter, wwithith tthehe aapprox.pprox. summersummer positionposition ofof thethe ITCZ.ITCZ. WSWS marksmarks thethe positionposition ofof thethe winter, when the ITCZ is positioned Wahiba Sand Sea. The dashed line in (b) represents the temporally occurring local convergence south of the equator, a persistent and H marks the approx. position of the winter high-pressure cell (modifi ed after Preusser high-pressure cell, accompanied by et al., 2002). weak wind and very low precipita- nual precipitation from the present a strengthening of monsoon circu- tion, establishes itself over central value of less than 100 mm to about lation associated with a northward Oman (Fig. 1b). 250 mm would be necessary to sus- shift of the ITCZ. tain such environmental conditions Changes in moisture availability Increased precipitation in (Radies et al., 2005). also had an impact on the sedimen- the past Evidence for the Early Holocene tary architecture of the Wahiba Sand Past humid periods are evidenced wet period is also recorded in the Sea. Between 170,000-140,000 and by the presence of ancient lake de- growth of speleothems. δ18O re- 120,000-100,000 yr ago, periodic posits in the south-western Rub’ al cords of the speleothems indicate a changes in moisture availability Khali of Saudi Arabia and Yemen rise in precipitation starting at about led to the establishment of a domi- (McClure, 1976; Lezine et al., 1998) 10,000 yr ago (Burns et al., 1998, nantly groundwater-controlled eo- and, more recently, in the Wahiba 2001; Fleitmann et al., 2003 a, b). lian architecture characterized by Sand Sea of eastern Oman (Radies The increase in precipitation is in- numerous paleosol horizons inter- et al., 2005). These deposits, based terpreted to result from a northward calated with dune deposits. This on radiocarbon and luminescence shift of the ITCZ that forced mois- implies that these periods were dating, are attributed to a period of ture from the Indian Ocean over the probably characterized by a high humid conditions during the early Arabian Peninsula. Speleothems variability of mean annual precipi- to middle Holocene (ca. 10,000 to from southern Arabia give evi- tation on a millennial scale. On the 5000 yr ago). Faunal assemblages dence for further humid periods in other hand, younger eolian depos- from the Wahiba Sand Sea reveal the past, dated by Th/U to 320,000- its formed between 35,000-8,000 that these lakes were permanent 300,000, 200,000-180,000, 135,000- yr ago show no evidence of paleo- with a developed shore margin en- 120,000, and 82,000-78,000 yr ago sol development, which implies vironment. The availability of water (Burns et al., 2001) (Fig. 2). All these that this period refl ects more pro- was suffi cient to sustain a vegeta- periods represent times of higher nounced arid conditions on a scale tion cover in the wider surroundings summer insolation on the northern of some ten thousand years (Radies of the lakes, attracting large herbi- hemisphere and correspond with et al., 2004; Preusser et al., 2005). vores, as indicated by the presence interglacial conditions in the mid- of dung beetle balls and cocoons. dle to high latitudes (apart from the Atmospheric circulation during Neolithic arrowheads, found in period 82,000-78,000 yr ago which glacial periods association with the former lake corresponds to pronounced inter- During times of insolation minima deposits, indicate the presence of stadial conditions). This indicates in the northern hemisphere, mon- human hunter communities in the that the Arabian Peninsula experi- soon precipitation was weaker than region. If all other climatic variables enced periods of higher mean an- today with the resultant more in- are kept constant, an increase in annual precipitation in the past due to tense arid conditions. These periods

PAGES NEWS, VOL.14, N°1, APRIL 2006 Science Highlights 39

�� most of the Quaternary and an ideal �� source area for the dust found in � Arabian Sea sediments. The most �� prominent input of dust in the Ara- �� bian Sea at around 110,000 yr ago �� concurs with the sudden drop of �� sea level immediately following �� the Last Interglacial (Fig. 2). This �� time is also characterized as the �� most prominent period of deposi- �� tion in the Wahiba Sand Sea. While �� Sirocko et al. (1991) favored a low- �� level atmospheric transport of dust �� towards the south, Preusser et al. �� (2002) suggest that the dust was �� fi rst transferred into the higher at- �� mosphere. The persistent NW-SE oriented jet stream present over Fig. 2: Comparison of CaCO3 contentcontent inin corecore 7070 KLKL (as(as anan inverseinverse measuremeasure ofof dustdust input),input), and the oxygen isotope record from core Md900963 from the Maldives area (as a measure the Arabian Peninsula could have of global ice volume and global sea level), with the timing of eolian deposition in the Wahiba transported the dust into higher at- Sand Sea. The individual duration of these periods was calculated from the standard deviation mospheric layers, across the ITCZ of weighted mean luminescence ages. Rose-diagrams show the distribution of sand transport vectors in the Wahiba Sand Sea from outcrop studies. Additionally shown are periods and released the material into the attributed to higher than present precipitation, as deduced from speleothem growth (modifi ed Arabian Sea. Alternatively, dust after Preusser et al., 2002). input into the Arabian Sea could of pronounced aridity are refl ected transport of sand grains towards have been derived from even more in the increase of terrestrial dust in the north. Luminescence dating of northerly sources, such as the inte- marine sediments of the Arabian several outcrops, together with two rior deserts of Iran and Afghanistan, Sea (Sirocko et al., 1991, 1993; Leus- sediment cores from the northern during winter months. A recent chner and Sirocko, 2000, 2003). The Wahiba Sand Sea, confi rms the cor- dust storm event in December 2003 increase of eolian input has been relation of sand accumulation with covered the Arabian Sea and south- explained by northwesterly winds periods characterized by prominent eastern Arabia for several days. transporting dust from the north decreases of global sea level (Fig. Both scenarios reconcile evidence towards the ITCZ. This implies that 2). The dating results indicate pe- from marine and continental envi- the ITCZ established a summer po- riods of pronounced eolian depo- ronments but imply that the ITCZ sition further south than today and sition in the northern part of the had a similar summer position over was located over the Arabian Sea Wahiba Sand Sea between 160,000- the eastern Arabian Peninsula dur- (Sirocko et al., 1991). While this sce- 140,000, 120,000-100,000, 78,000- ing glacial times as it has today. nario appears almost conclusive, it 64,000, and 22,000-18,000 yr ago has been questioned by recent evi- (Preusser et al., 2002). Moreover, REFERENCES dence from the Wahiba Sand Sea of dip directions of dune fore-sets in- Burns, S.J., Fleitmann, D., Matter, A., Neff, U. and Mangini, A., 2001: Speleothem evidence from eastern Oman (Fig. 1). dicate an exclusively northbound Oman for continental pluvial events during inter- The Wahiba Sand Sea is char- transport of sand. glacial periods. Geology, 29, 623-626. acterized by widespread eolian This evidence from continental Preusser, F., Radies, D. and Matter, A., 2002: A 160,000-Year record of dune development and sand deposits that partially form environments contradicts the as- atmospheric circulation in Southern Arabia. Sci- mega-dune ridges up to 70 m high. sumption by Sirocko et al. (1991, ence, 296: 2018-2020. The sand deposits comprise large 1993) that the ITCZ established a Radies, D., Preusser, F., Matter, A. and Mange, M., 2004: Eustatic and climatic controls on the amounts of bioclasts, such as shell summer position south of the Ara- development of the Wahiba Sand Sea, Sultanate debris, etc., implying a continen- bian Peninsula during glacial times. of Oman. Sedimentology, 51: 1359-1385. tal shelf source that was exposed In that case, the area of the Wahiba Radies, D., Hasiotis, S.T, Preusser, F., Neubert, E. during periods of low global sea Sand Sea would have been situated and Matter, A., 2005: Paleoclimatic signifi cance of Early Holocene faunal assemblages in wet level. Southerly winds transported north of the ITCZ and dominated by interdune deposits of the Wahiba Sand Sea, this sand from the shelf onto the winds with a southeasterly direc- Sultanate of Oman. Journal of Arid Environments, continent. Interestingly, the north- tion, which would have inhibited 62, 109-125. Sirocko, F., Sarnthein, M., Lange, H. and Erlenkeuser, ern margin of the area, covered the development of a sand sea with H., 1991: Atmospheric summer circulation and by large amounts of eolian sands, strong bioclastic input. Sirocko et coastal upwelling in the Arabian Sea during the coincides approx. with the south- al. (1991) concluded from the min- Holocene and the Last Glaciation. Quaternary Research, 36: 72-93. ern edge of the present position eralogical composition that the dust of the ITCZ during summer. At this probably derived from the Persian For full references please consult: position, wind velocity dissipates, Gulf area. The rather shallow Per- www.pages-igbp.org/products/newsletters/ref2006_1.html preventing any further substantial sian Gulf was a dry basin during

PAGES NEWS, VOL.14, N°1, APRIL 2006 40 Workshop Reports

2nd Southern Deserts Conference: “Human-environment interactions in southern hemisphere deserts—past, present and future”

ARICA, CHILE; 10-14 OCTOBER 2005

This four-day conference was designed to help develop a com- parative Southern Hemisphere perspective on the ways in which humans have interacted with and responded to the evolution of arid environments from prehistoric times to the present. It proved to be a very successful follow-up to the initial Southern Deserts Conference, held in Canberra, Australia, in Janu- ary 2003, and will be followed by a meeting in the third desert area of the hemisphere, southern Africa, in September 2008. The conference was structured Fig. 1: The post-conference ﬁ eld excursion group experiencing the driest place on Earth. into three symposia: ‘Late Qua- Although it never rains, riparian vegetation is supported by water from the mountains on the Altiplano. ternary Palaeoenvironments, Cli- mate and Culture’, ‘Resource Use The conference themes, and their program. Although South Ameri- in Pre-Historic, Pre-Industrial and integration, were investigated and can researchers have contributed Industrial Times’ and ‘Holocene cemented on pre-and post-confer- substantially to PAGES, a number and Modern Spatial and Social Or- ence excursions from the coast to of participants (especially arche- ganisation’, with almost all the 70 the Andean Altiplano along oasis ologists and those from elsewhere) or so registrants from 14 countries corridors. Dramatically marked by were unfamiliar with the organiza- presenting a paper or poster. There huge slope-covered geoglyphs, tion. An impressive background to was good coverage of all major these ancient traveling routes al- the new PAGES initiative on variabil- deserts across the Tropic of Capri- lowed maintenance of communi- ity in South American climate over corn but some real insights were cation between peoples across the the last 500-2000 years, featured provided into those from South centuries and indeed millennia. in the last PAGES News issue, was America, through an excellent and Prior to the conference, delegates presented by Martin Grosjean. comprehensive series of papers. traveled west from Arica into the As a consequence of the interdis- Although the ﬁ rst symposium was Andes to the Bolivian border, fol- ciplinary nature of the conference, most focused on PAGES activities, lowing Inca trails and appreciating there was a great deal of interaction the whole meeting was relevant to how pre-Incan Indigenous peoples between participants from diverse the spirit of PAGES and provided a harnessed and managed precious backgrounds. This interaction will be holistic feel of human-environment water, modified their landscapes maintained through joint involve- relationships. and commenced a history of ani- ment in the production of a pro- The strong messages emerging mal and plant domestication. The ceedings of the conference, planned from the meeting were: post-conference tour experienced for a special issue of ‘Chungara - the driest place on Earth, where it Revista de Antrepologia Chilena’. It 1. The diversity of deserts, with never rains; lakes and middens of appropriately focuses on integra- contrasts between the high- pollen sequences on the Altiplano; tion, by the writing of joint papers altitude desert of the Atacama, and archeology through the whole on particular themes arising from the sand deserts of southern time range of human occupation the conference. Africa and the ‘wet’ deserts of from the early Holocene, including Australia. the world’s oldest mummies, to a ACKNOWLEDGMENTS 2. The strong environmental con- nitrate mine settlement abandoned The conference was hosted by Centro de Investigaciones del Hombre en el Desi- trol over human settlement and in the 1970s and now a World Heri- erto, in association with the Universidad of development of culture in des- tage site. Tarapaca, and received sponsorship from ert environments. I welcomed the opportunity to PAGES. 3. The differences but also some experience and expand my knowl- PETER KERSHAW, notable similarities in human edge of this part of the world and to Monash University, Melbourne, Australia, adaptation to the various desert make the contacts that will facilitate [email protected] environments. integrated southern hemisphere projects as part of the new PAGES

PAGES NEWS, VOL.14, N°1, APRIL 2006 Workshop Reports 41

British-Russian workshop for young scientists: “Climate Change, the tree growth response, and reconstruction of climate”

KRASNOYARSK, RUSSIA; 25-29 JANUARY 2006

From 25-29 January, young researchers from the UK and Russia came together in Krasnoyarsk at a workshop organized by the Brit- ish Council, Russia (within the In- ternational Networking for Young Scientists program), in collaboration with the Climatic Research Unit (University of East Anglia, Norwich, UK; www.cru.uea.ac.uk) and the Sukachev Institute of For- est (Krasnoyarsk, Russia; http://forest.akadem.ru). The primary focus of the workshop was on dendro- climatology. Over the last decade or so, the number of reconstructions of global, or more particularly Northern Hemisphere, temperature changes during the last 1000-2000 years has proliferated, as the debate on the causes of recent warming has intensiﬁ ed. These new reconstructions, using variously selected combinations of proxy data and different statistical approaches in Fig. 1:Participants of the British-Russian workshop “Climate change, the tree growth response, their interpretation, have one thing and reconstruction of climate” (25 - 29 January 2006, Krasnoyarsk, Russia) in common: they are all heavily dependent on the information pro- • synthesis of the evidence for VLADIMIR SHISHOV vided by tree-ring data. climate change as derived Sukachev Institute of Forset, Akademgoro- In the depths of a severe Sibe- from different tree-ring pa- dok, Krasnoyarsk, Russia rian winter, students and young rameters (e.g. ring width, [email protected] researchers, all working within density and isotopic composi- KEITH BRIFFA this ﬁ eld, came together to make tion). University of East Anglia, Norwich, UK presentations describing their [email protected] work and to hear lectures given by This meeting provided a rare op- established researchers from the portunity to bring together young TOM MELVIN UK, USA and Russia. The talks and scientists from widely separated University of East Anglia, Norwich, UK [email protected] several round-table discussions parts of the globe and with wide- focused on issues directly related ranging specialties, allowing to the need for tree-ring studies them to re-examine their work to provide realistic estimates of in the context of climate change. past climatic changes. The topics It is hoped that it widened their included: horizons and suggested new approaches. It certainly broke down • chronology construction barriers and may even have initiat- methods and the preservation ed collaborations that will endure of long-timescale signals. for many years to come. • tree-growth modeling techniques and their value in cli- ACKNOWLEDGMENTS We wish to thank the British Council, mate reconstruction Russia for their provision of funding and • statistical methods for identi- their assistance in the logistics required fying optimal climate forcing in the arrangement of this workshop. We also wish to thank PAGES for their provi- on tree growth sion of funding for visiting experts.

PAGES NEWS, VOL.14, N°1, APRIL 2006 42 Workshop Reports

Global climate during Marine Isotope Stage 11 (MIS 11)

INQUA INTERNATIONAL WORKSHOP, LESVOS, GREECE; 5-7 SEPTEMBER 2005

The warm interval associated with Marine Isotope Stage 11 (MIS 11) approx. 400,000 years ago may be 0.05 an appropriate analog for the natu- Marine Isotope ral progression of the Holocene Stage 11 0.04 interglacial climate. Atmospheric (MIS 11) greenhouse gas concentrations

were very similar to pre-industrial Eccentricity (%) values, and the nearly circular or- 0 0 bit (low eccentricity) of the Earth

at that time resulted in similar sea- 300 Precession index sonal distributions of sunlight to today. The global climate response -0.04 at that time is less well known, and (ppm)

a number of efforts are underway 2

to improve our understanding of it. CO INQUA Project 0405 is focused on 200 the goals of facilitating and coordi- -380 nating research on MIS 11. A work- ) shop was held to assess the current state of knowledge of various as- -420 pects of the chronology; external forcing by insolation and internal Deuterium (‰ greenhouse-gas trapping of radia- 3.0

tion; sea level height/ice volume; O (‰) -460

carbon cycle; and the mean state, 18

a r 4.0

regional patterns, and variability of e

f 5e i n the climatic and environmental re- i m a sponses during MIS 11. r MIS 1 MIS 5 MIS 7 M MIS 9 MIS 11 MIS 13 o 5.0 The workshop was organized by Foraminifera F 0 100 200 300 400 500 Chronis Tzedakis at the University of the Aegean. Five key areas of re- Age (ka) search were identiﬁ ed: Fig. 1: Climate forcing and response over 0.5 million years. Eccentricity of Earth’s orbit and preces- 1) climate forcing during MIS 11 sional index (Berger and Loutre, 1991), atmospheric carbon-dioxide concentration (Petit et al., 1999; 2) absolute timing and duration Monnin et al., 2001; Siegenthaler et al., 2005), deuterium (δD) in Antarctica (Wolff et al., 2003), and of MIS 11 deep Atlantic benthic foraminifera oxygen isotope ratio (Oppo et al., 1998; McManus et al., 1999). 3) nature and magnitude of the climate response in different sons with the Holocene (Dominique North Atlantic, was discussed and parts of the Earth system, in- Raynaud). They also included a dis- compared to widespread evidence cluding spatial and temporal cussion of evidence for sea levels for similar marine conditions (Jerry patterns, and the presence of 20 ±10m higher than present, and McManus), followed by a synthe- stability or instability possible explanations for the ap- sis of research based on deep-sea 4) operation of the carbon cycle parent discrepancy between coral/ cores from the Australian margin 5) integration of paleo-data with shoreline and marine isotopic data (Peter Kershaw). Terrestrial evi- modelling studies (Jerry McManus). Additional pre- dence was presented using marine sentations from marine archives pollen sequences from the Iberian Presentations during the first included a demonstration of the margin that indicate the occurrence day focused on paleodata from ter- scale of coral reef growth at the on- of one long interglacial interval fol- restrial, ice and marine archives. set of MIS 11 (Andre Droxler) and lowed by three shorter oscillations These included results from the a discussion of evidence for pro- (Stephanie Desprat). A comparison EPICA Dome C ice core regarding nounced and prolonged marine car- of marine and terrestrial pollen the chronology of events, atmo- bonate dissolution from about 600 records from southern Europe in- spheric greenhouse concentrations, to 200 ka (Stephen Barker). A suite dicate that the most extensive tree the phasing between temperature, of proxies, indicating a long and population expansion during MIS 11

CO2 and CH4 changes, and compari- stable interglacial interval in the was coeval with both the insolation

PAGES NEWS, VOL.14, N°1, APRIL 2006 Workshop Reports 43

context of a longer term view of climate evolution over the last few million years (Tom Crowley). The oral presentations of the workshop were followed by a poster session and a roundtable discussion of the arising scientifi c issues. The fi nal day included presentations and discussion on the progress of the different study groups: Eurasian; Southern Hemisphere; Integration of marine, ice core and terrestrial records; Paleoclimate; and Carbon cycle. Progress was noted and gaps were identifi ed in each of these areas. The Lesvos workshop marked the mid-point of the INQUA inter-Congress period. Subsequent plans for the MIS 11 project include a workshop to be held at Woods Fig. 2: Group photo of the MIS-11 workshop participants in Lesvos, Greece. Hole in 2006, and a symposium to and atmospheric methane maxima inputs for the model (Marie-France be organized as part of the 17th IN- (Chronis Tzedakis), and some recent Loutre). Climate simulations using QUA Congress in Cairns, Australia high resolution work was presented the CLIMBER 2.3 model were pre- in 2007. from annually laminated sediments sented, showing the pronounced from maar lakes in the Eifel region, geographical differences in the na- JERRY MCMANUS Germany, which have the potential ture and timing of responses during Woods Hole Oceanographic Institution, Woods Hole, USA for constraining the duration of in- MIS 11 (Claudia Kubatzki). Addition- [email protected] terglacial warmth (Frank Sirocko). al experiments using the CLIMBER New results were also presented model, indicating the terrestrial CHRONIS TZEDAKIS from Lake Baikal, as was a synthe- realm as a climate amplifi er that University of Leeds, Leeds, UK sis of soil/loess sequences from had the potential to cause thresh- [email protected] China, Siberia and Russia (Sasha olds in the system to be crossed, Prokopenko). were also presented and examined The second morning of the in the context of the global carbon workshop was devoted to discus- cycle (Victor Brovkin). A new per- sions of models, including the respective on the entire problem of sults of recent simulations for MIS ice-age cycles was also presented, 11 using the MoBidiC climate model emphasizing the importance of put- that emphasized the importance of ting the variability of the last few identifying appropriate vegetation hundred thousand years in the

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PAGES NEWS, VOL.14, N°1, APRIL 2006 44 Last

CALENDAR 2006

May 26 - 29, 2006, Baile Herculane, Romania Aug. 21 - 25, 2006, Cambridge, UK IVth International Conference “Climate Change: the International Glaciological Society Symposium - Karst Record” (KR IV) Cryospheric Indicators of Global Climate Change

Further Information: Further Information: www.karst.ro/ www.igsoc.org/symposia/2006/cambridge/

June 11 - 17, 2006, Beijing, China Sept. 19 - 22, 2006, Bremen, Germany 7th International Conference on Dendrochronology: 6th European Coral Reef Conference Cultural Diversity, Environmental Variability Further Information: Further Information: http://isrs2006.zmt.uni-bremen.de/ http://7thicd.ibcas.ac.cn/pages/index.asp Oct. 24 - 27, 2006, Birmingham, UK July 17 - 21, 2006, Espoo, Finland Rapid Climate Change - International Science Living with Climate Variability and Change: Under- Conference standing the Uncertainties and Managing the Risks Further Information: Further Information: www.livingwithclimate.ﬁ / www.noc.soton.ac.uk/rapid/rapid2006/ Aug. 17 - 20, 2006, Bozeman, USA Nov. 9 - 12, 2006, Beijing, China American Quaternary Association (AMQUA) 36th ESSP Open Science Conference - Biennial Meeting - several PAGES-related sessions Global Environmental Change: Regional Challenges

Further Information: Further Information: www.pages-igbp.org/calendar/calendar06.html www.essp.org/essp/ESSP2006/

www.pages-igbp.org/calendar/calendar.html

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