Eemian Greenland Ice Sheet Simulated with a Higher-Order Model Shows Strong Sensitivity to Surface Mass Balance Forcing
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Cryogenian Glaciation and the Onset of Carbon-Isotope Decoupling” by N
CORRECTED 21 MAY 2010; SEE LAST PAGE REPORTS 13. J. Helbert, A. Maturilli, N. Mueller, in Venus Eds. (U.S. Geological Society Open-File Report 2005- M. F. Coffin, Eds. (Monograph 100, American Geophysical Geochemistry: Progress, Prospects, and New Missions 1271, Abstracts of the Annual Meeting of Planetary Union, Washington, DC, 1997), pp. 1–28. (Lunar and Planetary Institute, Houston, TX, 2009), abstr. Geologic Mappers, Washington, DC, 2005), pp. 20–21. 44. M. A. Bullock, D. H. Grinspoon, Icarus 150, 19 (2001). 2010. 25. E. R. Stofan, S. E. Smrekar, J. Helbert, P. Martin, 45. R. G. Strom, G. G. Schaber, D. D. Dawson, J. Geophys. 14. J. Helbert, A. Maturilli, Earth Planet. Sci. Lett. 285, 347 N. Mueller, Lunar Planet. Sci. XXXIX, abstr. 1033 Res. 99, 10,899 (1994). (2009). (2009). 46. K. M. Roberts, J. E. Guest, J. W. Head, M. G. Lancaster, 15. Coronae are circular volcano-tectonic features that are 26. B. D. Campbell et al., J. Geophys. Res. 97, 16,249 J. Geophys. Res. 97, 15,991 (1992). unique to Venus and have an average diameter of (1992). 47. C. R. K. Kilburn, in Encyclopedia of Volcanoes, ~250 km (5). They are defined by their circular and often 27. R. J. Phillips, N. R. Izenberg, Geophys. Res. Lett. 22, 1617 H. Sigurdsson, Ed. (Academic Press, San Diego, CA, radial fractures and always produce some form of volcanism. (1995). 2000), pp. 291–306. 16. G. E. McGill, S. J. Steenstrup, C. Barton, P. G. Ford, 28. C. M. Pieters et al., Science 234, 1379 (1986). 48. -
The Eemian - Local Sequences, Global Perspectives: Introduction
Geologie en Mijnbouw / Netherlands Journal of Geosciences 79 (2/3): 129-133 (2000) The Eemian - local sequences, global perspectives: introduction Thijs van Kolfschoten1 & Philip L. Gibbard2 1 Faculty of Archaeology, Leiden University, P.O. Box 9515, 2300 RA LEIDEN, the Netherlands; Corresponding author; e-mail: [email protected] 2 Godwin Institute of Quaternary Research, Department of Geography, University of Cambridge, Downing Street, CAMBRIDGE CB2 3EN, England; e-mail:[email protected] Received: May 2000; accepted in revised form: 20 June 2000 G The history of this special issue gation and discussion on the Middle/Late Pleistocene boundary on the original type area of the Eemian in The history of this volume goes back to a 1973 IN- the Netherlands. The Eemian sequence was often QUA congress in New Zealand, where an INQUA used as reference and furthermore the term 'Eemian' Commission of Stratigraphy working group on major was widely used to identify the last interglacial far be subdivisions of the Pleistocene was established. The yond western central Europe. Examination of the Pleistocene series/epoch was hitherto generally subdi available data from the Eemian type area showed that vided into the Lower/Early, Middle and Upper/Late a re-evaluation of existing data and collection of criti Pleistocene (see, among others, Zeuner, 1935, 1959) cal new data were needed to define an unambiguous but the boundaries between these subseries/sube- stratigraphical boundary. Although the identification pochs were not formally defined. The boundary be of boundaries is central to stratigraphical subdivision, tween the Early and Middle Pleistocene was, in the it is nevertheless the Eemian as an entity that is of European literature, put at the base of the Cromerian particular interest for understanding the development Complex (Zagwijn, 1963) or at the Brunhes/Matuya- of a complete interglacial cycle. -
Sea Level and Global Ice Volumes from the Last Glacial Maximum to the Holocene
Sea level and global ice volumes from the Last Glacial Maximum to the Holocene Kurt Lambecka,b,1, Hélène Roubya,b, Anthony Purcella, Yiying Sunc, and Malcolm Sambridgea aResearch School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia; bLaboratoire de Géologie de l’École Normale Supérieure, UMR 8538 du CNRS, 75231 Paris, France; and cDepartment of Earth Sciences, University of Hong Kong, Hong Kong, China This contribution is part of the special series of Inaugural Articles by members of the National Academy of Sciences elected in 2009. Contributed by Kurt Lambeck, September 12, 2014 (sent for review July 1, 2014; reviewed by Edouard Bard, Jerry X. Mitrovica, and Peter U. Clark) The major cause of sea-level change during ice ages is the exchange for the Holocene for which the direct measures of past sea level are of water between ice and ocean and the planet’s dynamic response relatively abundant, for example, exhibit differences both in phase to the changing surface load. Inversion of ∼1,000 observations for and in noise characteristics between the two data [compare, for the past 35,000 y from localities far from former ice margins has example, the Holocene parts of oxygen isotope records from the provided new constraints on the fluctuation of ice volume in this Pacific (9) and from two Red Sea cores (10)]. interval. Key results are: (i) a rapid final fall in global sea level of Past sea level is measured with respect to its present position ∼40 m in <2,000 y at the onset of the glacial maximum ∼30,000 y and contains information on both land movement and changes in before present (30 ka BP); (ii) a slow fall to −134 m from 29 to 21 ka ocean volume. -
Safeguarding the Arctic Why the U.S
Safeguarding the Arctic Why the U.S. Must Lead in the High North By Cathleen Kelly and Miranda Peterson January 22, 2015 “As the United States assumes the Chairmanship of the Arctic Council, it is more important than ever that we have a coordinated national effort that takes advantage of our combined expertise and efforts in the Arctic region to promote our shared values and priorities.” — President Obama, Executive Order on Enhancing Coordination of National Efforts in the Arctic, January 21, 20151 While many Americans do not consider the United States to be an Arctic nation, Alaska—which constitutes 16 percent of the country’s landmass and sits on the Arctic Circle—puts the country solidly in that category.2 Consequently, it is with good reason that the United States has a seat on the Arctic Council. As Arctic warming accelerates, U.S. leadership in the High North is key not only to the public health and safety of Americans and other people in the region, but also to U.S. national security and the fate of the planet. In just three months, U.S. Secretary of State John Kerry will become chairman of the Arctic Council. The two-year position rotates among the eight Arctic nations3—Canada, Finland, Iceland, Norway, Russia, Sweden, the United States, and Denmark, including Greenland and the Faroe Islands—and is a powerful platform for shaping how the risks and opportunities of increasing commercial activity at the top of the world are managed. To ready the administration for Secretary Kerry’s turn to hold the Arctic Council gavel from 2015 to 2017, President Barack Obama recently issued an executive order to better coordinate national efforts in the Arctic.4 The executive order is the latest signal from the White House that President Obama and Secretary Kerry are focused on preparing the nation for dramatic changes in the Arctic and protecting U.S. -
Ice-Core Dating of the Pleistocene/Holocene
[RADIOCARBON, VOL 28, No. 2A, 1986, P 284-291] ICE-CORE DATING OF THE PLEISTOCENE/HOLOCENE BOUNDARY APPLIED TO A CALIBRATION OF THE 14C TIME SCALE CLAUS U HAMMER, HENRIK B CLAUSEN Geophysical Isotope Laboratory, University of Copenhagen and HENRIK TAUBER National Museum, Copenhagen, Denmark ABSTRACT. Seasonal variations in 180 content, in acidity, and in dust content have been used to count annual layers in the Dye 3 deep ice core back to the Late Glacial. In this way the Pleistocene/Holocene boundary has been absolutely dated to 8770 BC with an estimated error limit of ± 150 years. If compared to the conventional 14C age of the same boundary a 0140 14C value of 4C = 53 ± 13%o is obtained. This value suggests that levels during the Late Glacial were not substantially higher than during the Postglacial. INTRODUCTION Ice-core dating is an independent method of absolute dating based on counting of individual annual layers in large ice sheets. The annual layers are marked by seasonal variations in 180, acid fallout, and dust (micro- particle) content (Hammer et al, 1978; Hammer, 1980). Other parameters also vary seasonally over the annual ice layers, but the large number of sam- ples needed for accurate dating limits the possible parameters to the three mentioned above. If accumulation rates on the central parts of polar ice sheets exceed 0.20m of ice per year, seasonal variations in 180 may be discerned back to ca 8000 BP. In deeper strata, ice layer thinning and diffusion of the isotopes tend to obliterate the seasonal 5 pattern.1 Seasonal variations in acid fallout and dust content can be traced further back in time as they are less affected by diffusion in ice. -
Polar Ice Coring and IGY 1957-58 in This Issue
NEWSLETTER OF T H E N A T I O N A L I C E C O R E L ABORATORY — S CIE N C E M A N AGE M E N T O FFICE Vol. 3 Issue 1 • SPRING 2008 Polar Ice Coring and IGY 1957-58 In this issue . An Interview with Dr. Anthony J. “Tony” Gow Polar Ice Coring and IGY 1957-58 From the early 1950’s through the mid-1960’s, U.S. polar ice coring research was led by two U.S. Army An Interview with Dr. Tony Gow .... 1 Corps of Engineers research labs: the Snow, Ice, and Permafrost Research Establishment (SIPRE), and Upcoming Meetings ...................... 2 later, the Cold Regions Research and Engineering Laboratory (CRREL). One of the high-priority research Greenland Science projects recommended by the U.S. National Academy of Sciences/National Committee for IGY 1957-58 and Education Week ..................... 3 was to deep core drill into polar ice sheets for scientific purposes. To this end, SIPRE was tasked with Ice Core Working Group developing and running the entire U.S. ice core drilling and research program. Following the successful Members ....................................... 3 pre-IGY pilot drilling trials at Site-2 NW Greenland in 1956 (305 m) and 1957 (411 m), the SIPRE WAIS Divide turned their attention to deep ice core drilling in Antarctica for IGY 1957-58. Dr. Anthony J. (Tony) Ice Core Update ............................ 5 Gow (CRREL, retired) was one of the scientists on the project. In March 2008, the NICL-SMO had Ice Cores and POLAR-PALOOZA the opportunity to sit down with Dr. -
Coupled Simulations of the Greenland Ice Sheet: Eemian
Coupled simulations of the Greenland ice sheet: Eemian Alexander Robinson CESM Workshop, Cross Working Group Session Monday, 17 June 2019 Greenland during the Eemian Camp Century NEEM • Eemian age (130-115 kyr ago) ice found at Summit and NEEM, Summit deposited upstream. • DYE-3 and Camp Century show tenuous DYE-3 evidence for ice but no climatic information. Credit: NASA Greenland during the Eemian Camp Century NEEM • Southern ice sheet remained intact given significant glacial Summit discharge and only a small increase in DYE-3 pollen. Credit: NASA MIS-5 MIS-11 kyr ago Reyes et al. (2014) Greenland during the Eemian Camp Century NEEM • Southern ice sheet remained intact given significant glacial Summit discharge and only a small increase in DYE-3 pollen. Credit: NASA Greenland during the Eemian Camp Century NEEM • Southern ice sheet remained intact given significant glacial Summit discharge and only a small increase in DYE-3 pollen. • Temperatures were warmer than today… Credit: NASA Greenland during the Eemian Capron et al. (2014) • Data show peak warming up to Multi-model 5°C around 129 kyr ago, sustained mean (Bakker et al., 2013) anomalies through the Eemian. X • Climate models cannot capture X this transient pattern so far. X X Greenland during the Eemian • Summit and NEEM δ18O signals are remarkably similar. • Reconstructed warming reaches 6- 8°C assuming no ice elevation changes. • Seasonality? δ18O conversion? How can we reconcile models and reconstructions? • Transient coupled climate – ice sheet simulations • Ensembles to test uncertainty Methods Robinson et al., 2010 REMBO *Temperature Daily melt *Annual accum. SICOPOLIS climate model *Precipitation model *Annual ablation *Annual temp. -
Impacts of Glacial Meltwater on Geochemistry and Discharge of Alpine Proglacial Streams in the Wind River Range, Wyoming, USA
Brigham Young University BYU ScholarsArchive Theses and Dissertations 2019-07-01 Impacts of Glacial Meltwater on Geochemistry and Discharge of Alpine Proglacial Streams in the Wind River Range, Wyoming, USA Natalie Shepherd Barkdull Brigham Young University Follow this and additional works at: https://scholarsarchive.byu.edu/etd BYU ScholarsArchive Citation Barkdull, Natalie Shepherd, "Impacts of Glacial Meltwater on Geochemistry and Discharge of Alpine Proglacial Streams in the Wind River Range, Wyoming, USA" (2019). Theses and Dissertations. 8590. https://scholarsarchive.byu.edu/etd/8590 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Impacts of Glacial Meltwater on Geochemistry and Discharge of Alpine Proglacial Streams in the Wind River Range, Wyoming, USA Natalie Shepherd Barkdull A thesis submitted to the faculty of Brigham Young University in partial fulfillment of the requirements for the degree of Master of Science Gregory T. Carling, Chair Barry R. Bickmore Stephen T. Nelson Department of Geological Sciences Brigham Young University Copyright © 2019 Natalie Shepherd Barkdull All Rights Reserved ABSTRACT Impacts of Glacial Meltwater on Geochemistry and Discharge of Alpine Proglacial Streams in the Wind River Range, Wyoming, USA Natalie Shepherd Barkdull Department of Geological Sciences, BYU Master of Science Shrinking alpine glaciers alter the geochemistry of sensitive mountain streams by exposing reactive freshly-weathered bedrock and releasing decades of atmospherically-deposited trace elements from glacier ice. Changes in the timing and quantity of glacial melt also affect discharge and temperature of alpine streams. -
“Mining” Water Ice on Mars an Assessment of ISRU Options in Support of Future Human Missions
National Aeronautics and Space Administration “Mining” Water Ice on Mars An Assessment of ISRU Options in Support of Future Human Missions Stephen Hoffman, Alida Andrews, Kevin Watts July 2016 Agenda • Introduction • What kind of water ice are we talking about • Options for accessing the water ice • Drilling Options • “Mining” Options • EMC scenario and requirements • Recommendations and future work Acknowledgement • The authors of this report learned much during the process of researching the technologies and operations associated with drilling into icy deposits and extract water from those deposits. We would like to acknowledge the support and advice provided by the following individuals and their organizations: – Brian Glass, PhD, NASA Ames Research Center – Robert Haehnel, PhD, U.S. Army Corps of Engineers/Cold Regions Research and Engineering Laboratory – Patrick Haggerty, National Science Foundation/Geosciences/Polar Programs – Jennifer Mercer, PhD, National Science Foundation/Geosciences/Polar Programs – Frank Rack, PhD, University of Nebraska-Lincoln – Jason Weale, U.S. Army Corps of Engineers/Cold Regions Research and Engineering Laboratory Mining Water Ice on Mars INTRODUCTION Background • Addendum to M-WIP study, addressing one of the areas not fully covered in this report: accessing and mining water ice if it is present in certain glacier-like forms – The M-WIP report is available at http://mepag.nasa.gov/reports.cfm • The First Landing Site/Exploration Zone Workshop for Human Missions to Mars (October 2015) set the target -
The History of Ice on Earth by Michael Marshall
The history of ice on Earth By Michael Marshall Primitive humans, clad in animal skins, trekking across vast expanses of ice in a desperate search to find food. That’s the image that comes to mind when most of us think about an ice age. But in fact there have been many ice ages, most of them long before humans made their first appearance. And the familiar picture of an ice age is of a comparatively mild one: others were so severe that the entire Earth froze over, for tens or even hundreds of millions of years. In fact, the planet seems to have three main settings: “greenhouse”, when tropical temperatures extend to the polesand there are no ice sheets at all; “icehouse”, when there is some permanent ice, although its extent varies greatly; and “snowball”, in which the planet’s entire surface is frozen over. Why the ice periodically advances – and why it retreats again – is a mystery that glaciologists have only just started to unravel. Here’s our recap of all the back and forth they’re trying to explain. Snowball Earth 2.4 to 2.1 billion years ago The Huronian glaciation is the oldest ice age we know about. The Earth was just over 2 billion years old, and home only to unicellular life-forms. The early stages of the Huronian, from 2.4 to 2.3 billion years ago, seem to have been particularly severe, with the entire planet frozen over in the first “snowball Earth”. This may have been triggered by a 250-million-year lull in volcanic activity, which would have meant less carbon dioxide being pumped into the atmosphere, and a reduced greenhouse effect. -
Ice Core Science
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. -
Timing and Tempo of the Great Oxidation Event
Timing and tempo of the Great Oxidation Event Ashley P. Gumsleya,1, Kevin R. Chamberlainb,c, Wouter Bleekerd, Ulf Söderlunda,e, Michiel O. de Kockf, Emilie R. Larssona, and Andrey Bekkerg,f aDepartment of Geology, Lund University, Lund 223 62, Sweden; bDepartment of Geology and Geophysics, University of Wyoming, Laramie, WY 82071; cFaculty of Geology and Geography, Tomsk State University, Tomsk 634050, Russia; dGeological Survey of Canada, Ottawa, ON K1A 0E8, Canada; eDepartment of Geosciences, Swedish Museum of Natural History, Stockholm 104 05, Sweden; fDepartment of Geology, University of Johannesburg, Auckland Park 2006, South Africa; and gDepartment of Earth Sciences, University of California, Riverside, CA 92521 Edited by Mark H. Thiemens, University of California, San Diego, La Jolla, CA, and approved December 27, 2016 (received for review June 11, 2016) The first significant buildup in atmospheric oxygen, the Great situ secondary ion mass spectrometry (SIMS) on microbaddeleyite Oxidation Event (GOE), began in the early Paleoproterozoic in grains coupled with precise isotope dilution thermal ionization association with global glaciations and continued until the end of mass spectrometry (ID-TIMS) and paleomagnetic studies, we re- the Lomagundi carbon isotope excursion ca. 2,060 Ma. The exact solve these uncertainties by obtaining accurate and precise ages timing of and relationships among these events are debated for the volcanic Ongeluk Formation and related intrusions in because of poor age constraints and contradictory stratigraphic South Africa. These ages lead to a more coherent global per- correlations. Here, we show that the first Paleoproterozoic global spective on the timing and tempo of the GOE and associated glaciation and the onset of the GOE occurred between ca.