DOCSLIB.ORG

Fast-Ice Properties and Structure in Mcmurdo Sound

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Fast-Ice Properties and Structure in Mcmurdo Sound Fast-ice properties 00 0, C6 001 MW 00 O 0 A 00 and structure in McMurdo Sound 00000 0 O 0 qM0 = 0 O 0 Dc•= 0 0000 D 0 ooa 50 O 0 41110 m 50 M.O. JEFFRIES and WE WEEKS cc. O 0 00aoo O 0 000 DO Geophysical Institute 0 0O 00 DD University of Alaska 100 o CDCOM 0 DO D 0 D 100 Fairbanks, Alaska 99775-0800 M 00 DO •= 0 oo 00 _ 0 —I I 0 0 41KE 0 O 0 0 C) The fast ice in McMurdo Sound frequently is used as a plat- 3 o acmgo 0 DO DO 000 0 O 0 _ 0 form for oceanographic and biological studies, and the annual 150 0 150 0= 00 O 0 a0 sea ice runway is essential to the movement of personnel, cze 00 0 O 0 DO equipment and supplies in and out of McMurdo Station. Con- O Da 0:2CM 8 sidering the importance of the fast ice to the operation of coo o 0 o McMurdo Station remarkably little is known about its annual 200 000 GOD 0 200 OO SO 0 growth history, properties, and structure. In early January 1991, 00• 0 we obtained 15 first-year cores from the fast ice in McMurdo 0 •0 0 Sound (figure 1). For comparative purposes, an additional core A B 250 .... 250 was obtained from Gerlache Bay, the site of the Italian antarctic 0 2 4 6 8 10-4 -3 -2 -1 0 station, Baie Terra Nova (see Jeffries and Weeks, Antarctic Jour- SALINITY (o/oo) TEMPERATURE (°C) nal, this issue, for location). Here we report some preliminary results of the ice core analysis program. Figure 2. Depth profiles of salinity and temperature in McMurdo The mean salinity of the individual fast ice cores ranged from Sound fast ice cores. The solid symbols (circles for salinity, 2.95 to 5.39 parts per thousand. The mean value of all the fast squares for temperature) represent the mean values of the open ice salinity measurements was 4.21 parts per thousand. This symbols at a given depth. (% denotes parts per thousand. cm value, only slightly less than that of the western Ross Sea pack denotes centimeter.) ice (Jeffries and Weeks, Antarctic Journal, this issue), is evidence of brine loss prior to sampling. Some idea of the magnitude of the brine loss in 1991 can be gained from the reported mean salinity of 6.0 parts per thousand for the McMurdo fast ice in issue). Like the pack ice, the fast ice is also more saline than October through November 1980 (Gow et al. 1982). arctic sea ice of similar age and thickness. Also similar to the The mean salinity profile in the fast ice has a roughly reverse western Ross Sea pack ice (Jeffries and Weeks, Antarctic Journal, S-shape (figure 2A), which almost certainly is the result of this issue), the fast ice, although close to the melting point and desalination. The relationship between mean ice salinity (S i, in nearly isothermal (figure 2B), nevertheless retains a consider- parts per thousand) and mean ice thickness (h, in meters) of able amount of brine. the fast ice, S = 0.007h + 2.846, is similar to that of the western The mean ice thickness at the 16 sites ranged from 1.25 to Ross Sea pack ice (Jeffries and Weeks, Antarctic Journal, this 2.32 meters. The mean value of all the ice thickness measure- ments was 1.94 meters. The data are consistent with recent fast ice thickness records for McMurdo Sound and adjacent waters (Leventer et al. 1987). The fast ice is almost twice as thick as the western Ross Sea pack ice (Jeffries and Weeks, Antarctic 164 - C 166 C 166, 0 a Point Journal, this issue). The greater thickness of the fast ice might ARS-33 A be caused by a combination of lower oceanic heat fluxes and .W. Point RS-24 Bornacchi MCMURDO different ice accretion mechanisms in the fast ice zones. Congelation ice (figure 3) was observed at all fast ice sites, R23 SOUND :Cape Royda comprising from 30.4 percent to 93.6 percent of the individual cores. This ice type often was characterized by strongly aligned RS-27 A crystals, a feature also observed at many McMurdo Sound lo- RS-22 Cops cations in October through November 1980 (Cow et al. 1982). A A A 70,%, RS-34 RS-32 The preferred orientation of congelation ice crystals in the Erebus Tongue CI A McMurdo Sound area is consistent with water current control The Strand A ERE Mo,oi,.. RS-21 RS-31 77 of crystal growth (Weeks and Cow 1978). Frazil ice, found only DAY A -- at the top of core RS-19 (figure 3) was a minor component of RS-25 - - - the fast ice. McMurdo 00050 /Station land, - RS-2OA Unlike the western Ross Sea pack ice (Jeffries and Weeks, VA0. McMurdo los SPoil Antarctic Journal, RS-29 RS730 RS-19 this issue), the lower portions of most fast ice hoop cores comprised layers of congealed, densely packed platelet 164 , Z------ ice (figure 3). The maximum percentage of platelet ice observed in a core was 50.7 percent. Only core RS-31, obtained from Figure 1. Location map of the sites of ice cores (triangles) obtained Erebus Bay, did not contain an appreciable amount of platelet from the McMurdo Sound fast ice in January 1991. ice (figure 3). 94 ANTARCTIC JOURNAL ice sheet has been noted since the 1960s (Paige 1966; Lewis and Perkin 1985; Cow personal communication). The occur- rence of platelet ice in the Gerlache Bay fast ice (Core RS-17, C figure 3) was somewhat unexpected, but it suggests a nearby source of low-density water for platelet ice growth. At Cerlache fflw Bay, the inclusion of platelets in the congelation ice clearly be- gan somewhat earlier than in McMurdo Sound. This was inter- c/p rupted before resuming and then dominating the ice-accretion 1111 process (figure 3). IIIIIIIIIIH This work was supported by National Science Foundation p...,.I c/p grant DPP 89-15863. Thanks go to the helicopter pilots and I....., •••4 crews of the U.S. Navy VXE-6 Squadron and the U.S. Coast ,.••..i•••••4 •••••••....••i Guards Polar Sea Aviation Detachment for flying us around i•••••I••••• P••••••4I•••••4 )•••••••••• McMurdo Sound and cheerfully assisting us with our work. W••.•••i I••••••4••••••4 •A•A•A ••.&•.• ))1)1) P!.!.! The Cerlache Bay core was obtained with the assistance of the Polar Sea. Figure 3. Diagrammatic representations of the stratigraphy of References some fast ice cores from McMurdo Sound (RS-19, RS-33, RS-31) and Gerlache Bay (RS-17). F denotes frazil ice; C denotes conge- Cow, A.J. 1991. Personal communication. lation ice; P denotes platelet ice; C/p denotes congelation ice with Cow, A.J., S.F Ackley, WE Weeks, and J.W. Covoni. 1982. Physical some platelets. and structural characteristics of Antarctic sea ice. Annals of Glaciology, 3, 113-117 Jeffries, MO., and WE Weeks. 1991. Summer pack-ice properties and structure in the western Ross Sea. Antarctic Journal of the U.S., 26(5). It is believed that platelet ice growth in McMurdo Sound Leventer, A., R.B. Dunbar, M.R. Allen, and R.V. Wayper. 1987 Ice results from supercooling brought about by adiabatic de- thickness in McMurdo Sound. Antarctic Journal of the U.S., 22(5), 94- compression of low density seawater flowing northward into 96. the sound from below the McMurdo Ice Shelf (Lewis and Perkin Lewis, E.L., and R. Perkin. 1985. The winter oceanography of Mc- 1985). The accretion of the platelet ice against the base of the Murdo Sound, Antarctica. In S.S. Jacobs (Ed.), Oceanology of the Ant- overlying congelation ice sheet and its subsequent consolida- arctic Continental Shelf. (Antarctic Research Series, Vol. 43.) Washing- ton, D.C.: American Geophysical Union. tion allows increased growth of the fast ice, resulting in a final Paige, R.A. 1966. Crystallographic studies of sea ice in McMurdo Sound, thickness greater than would otherwise be possible by heat Antarctica. (Technical Report R494.) Port Hueneme, Calif.: Naval Civil conduction from platelet-free water alone. Engineering Laboratory. The basic two-layer structure of the McMurdo fast ice, i.e., Weeks, WE, and A.J. Cow. 1978. Preferred crystal orientations in the congelation ice overlying platelet ice, undoubtedly is a recurrent fast ice along the margins of the Arctic Ocean. Journal of Geophysical feature. The significant contribution of platelet ice to the fast Research, 83(C10), 5105-5121. Summer pack-ice 1991. Ice thicknesses, salinities, temperatures, and structural- stratigraphic data from 17 cores are discussed. properties and structure The mean thickness of the sampled floes ranged from 0.59 in the western Ross Sea to 1.53 meters. The mean value of all the ice thickness mea- surements is 1.09 meters. The ice thickness statistics are similar to the more extensive ice thickness observations obtained from M.O. JEFFRIES and WE WEEKS the Weddell Sea (Cow et al. 1987; Wadhams et al. 1987; Lange and Eicken 1991). The Ross Sea ice thickness data complement Geophysical Institute previous observations that antarctic sea ice is thinner than arc- University of Alaska tic sea ice of similar age. Fairbanks, Alaska 99775-0800 The mean salinity of the individual cores ranged from 3.44 to 6.01 parts per thousand. The mean value of all the pack ice Most of the available information on the properties and struc- salinity measurements was 4.5 parts per thousand.
Load more

Recommended publications
  • Ice Production in Ross Ice Shelf Polynyas During 2017–2018 from Sentinel–1 SAR Images
    remote sensing Article Ice Production in Ross Ice Shelf Polynyas during 2017–2018 from Sentinel–1 SAR Images Liyun Dai 1,2, Hongjie Xie 2,3,* , Stephen F. Ackley 2,3 and Alberto M. Mestas-Nuñez 2,3 1 Key Laboratory of Remote Sensing of Gansu Province, Heihe Remote Sensing Experimental Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China; [email protected] 2 Laboratory for Remote Sensing and Geoinformatics, Department of Geological Sciences, University of Texas at San Antonio, San Antonio, TX 78249, USA; [email protected] (S.F.A.); [email protected] (A.M.M.-N.) 3 Center for Advanced Measurements in Extreme Environments, University of Texas at San Antonio, San Antonio, TX 78249, USA * Correspondence: [email protected]; Tel.: +1-210-4585445 Received: 21 April 2020; Accepted: 5 May 2020; Published: 7 May 2020 Abstract: High sea ice production (SIP) generates high-salinity water, thus, influencing the global thermohaline circulation. Estimation from passive microwave data and heat flux models have indicated that the Ross Ice Shelf polynya (RISP) may be the highest SIP region in the Southern Oceans. However, the coarse spatial resolution of passive microwave data limited the accuracy of these estimates. The Sentinel-1 Synthetic Aperture Radar dataset with high spatial and temporal resolution provides an unprecedented opportunity to more accurately distinguish both polynya area/extent and occurrence. In this study, the SIPs of RISP and McMurdo Sound polynya (MSP) from 1 March–30 November 2017 and 2018 are calculated based on Sentinel-1 SAR data (for area/extent) and AMSR2 data (for ice thickness).
    [Show full text]
  • Particle Flux Beneath Fast Ice in the Shallow Southwestern Beaufort Sea, Arctic Ocean
    MARINE ECOLOGY - PROGRESS SERIES Published October 28 Mar. Ecol. Prog. Ser. 1 Particle flux beneath fast ice in the shallow southwestern Beaufort Sea, Arctic Ocean Andrew G.Carey, Jr. College of Oceanography, Oregon State University. Corvallis. Oregon 97331, USA ABSTRACT: Flux of organic particulate materials under sea ice to the benthic environment was measured in the nearshore Arctic Ocean during spring 1980. Downward flux of organic carbon started early in the spring and continued at fairly uniform but low levels (approximately 1 % of daily carbon production of ice algae) from April until early June. Particulate organic nitrogen flux tended to be low and erratic. Fecal pellets from 2 crustacean species were among the few recognizable large particles. The amphipod Pseudalibrotus (= Onisimus) litoralis, normally a benthic species, lives in spring on the undersurface of sea ice in the shallow polar environment. Collected pellets from adults decreased through spring, while those from juveniles increased until 5 Jun when their flux declined markedly. Late in spring these pellets contained primarily pennate diatom frustules from the ice algal bloom. Crustacean molts and Mysis relicta fecal pellets were also present, particularly in April and early May. The sinking particles were derived from both the pelagic and ice environments, although most of the material appeared to be from the ice biota. Data suggest that particles falling from the productive ice community during spring are a carbon source for the benthos; one that is small but available
    [Show full text]
  • February 1992 2 Contents Continued
    February. 1992 BULLETIN HOUSTON GEOLOGICAL SOCIETY SEISMIC STRATIGRAPHIC MODEL OF A FAILED SHELF EDGE UPDIP LIMIT OF THE HACKBERRY EMBAYMENT, SW LOUISIANA HACKBERRY SEQUENCE BOUNDARY 0 1 2 HIGHSTAND SYSTEMS TRACT I I I 1 I TRANSGRESSIVE SYSTEMS TRACT TST MILES LOWSTAND SYSTEMS TRACT LST YERTXAL EXMKIERATION - 11 DOWNLAP SURFACE DLS HACKBERRY SHALE LOWER HACKBERRY SHALE & SANDSTONE Find out more about the Hackberry Depositional System at the HGS Luncheon on Wednesday, February 26,1992. HAPPY VALENTINE'S DAY! IN THIS ISSUE. .. - Spotlight on Caspian Sea ....................................... Page 18 - Land and Sea of the Midnight Sun .............................. Page 20 - Household Hazardous Waste: Cleaning Products ................ Page 22 - Status Report of Superfund Sites in Harris County. .............. Page 24 PLUS MORE! (For February Events, see Calendar and Geo-events section, page 31) THE TIME IS RIGHT NOW TO ADVERTISE IN THE BULLETIN AND THE DIRECTORY ACCESS AN INFLUENTIAL AND VAHED GEO-TECHNICAL / MANAGEMENT MARKETPLACE : MEMEMBERSHIP AND SUBSCABERS Of THE HOUSTON GEOLOGICAL SOClETY USE MEAPPLICATION FOFM PROVIDED BELOW OR COHTACT MEHGS OFRCE FOR ADDmONAL DETAILS PNIllAL YEAR ADVERIWNG RATES FOR MEHGS klOHnY BULLETIN WILL BE PROVIDED UPON REQUEST 1991-1992 ADVERnSlNG RATES FOR THE HOUSTON GEOLOGlCAL SOCIETY - MONTHLY BULLETIN AND ANNUAL MECTORY DATE: Houston Geologrcal Sodety COMPANY: 7171 Hdn.Sulte 314 Houston. Texas 77036 ADDRESS: Fax: (713) 785-0553 Buslness Phone: (713) 7856402 PHONE: ( ) Please call from 8:00 AM to 2:00
    [Show full text]
  • Ikaite Crystal Distribution in Winter Sea Ice and Implications for CO2 System Dynamics
    EGU Journal Logos (RGB) Open Access Open Access Open Access Advances in Annales Nonlinear Processes Geosciences Geophysicae in Geophysics Open Access Open Access Natural Hazards Natural Hazards and Earth System and Earth System Sciences Sciences Discussions Open Access Open Access Atmospheric Atmospheric Chemistry Chemistry and Physics and Physics Discussions Open Access Open Access Atmospheric Atmospheric Measurement Measurement Techniques Techniques Discussions Open Access Open Access Biogeosciences Biogeosciences Discussions Open Access Open Access Climate Climate of the Past of the Past Discussions Open Access Open Access Earth System Earth System Dynamics Dynamics Discussions Open Access Geoscientific Geoscientific Open Access Instrumentation Instrumentation Methods and Methods and Data Systems Data Systems Discussions Open Access Open Access Geoscientific Geoscientific Model Development Model Development Discussions Open Access Open Access Hydrology and Hydrology and Earth System Earth System Sciences Sciences Discussions Open Access Open Access Ocean Science Ocean Science Discussions Open Access Open Access Solid Earth Solid Earth Discussions The Cryosphere, 7, 707–718, 2013 Open Access Open Access www.the-cryosphere.net/7/707/2013/ The Cryosphere doi:10.5194/tc-7-707-2013 The Cryosphere Discussions © Author(s) 2013. CC Attribution 3.0 License. Ikaite crystal distribution in winter sea ice and implications for CO2 system dynamics S. Rysgaard1,2,3,4, D. H. Søgaard3,6, M. Cooper2, M. Pucko´ 1, K. Lennert3, T. N. Papakyriakou1, F.
    [Show full text]
  • Establishing a Greenland Ice Sheet Ocean Observing System (Grioos)
    Establishing a Greenland Ice Sheet Ocean Observing System (GriOOS) Report from an International Workshop December 12-13, 2015 Fort Mason, San Francisco, CA, USA Editors: Fiammetta Straneo (Scripps, UCSD) Twila Moon (NSIDC) Dave Sutherland (U. Oregon) Patrick Heimbach (U. Texas) Ginny Catania (U. Texas). 1 2 Table of Contents Executive Summary ............................................................................................................................. 4 Introduction ........................................................................................................................................... 6 GrIOOS Design and Requirements .................................................................................................. 6 1. Why establish GrIOOS? ............................................................................................................................. 8 2. What are the essential variables to be measured? .......................................................................... 8 3. What measurements exist already? ..................................................................................................... 8 A. Atmospheric .................................................................................................................................................................. 8 B. Seismic and Geodesy ................................................................................................................................................. 9 C. Ocean ...............................................................................................................................................................................
    [Show full text]
  • First Estimates of the Contribution of Caco3 Precipitation to the Release
    1 First estimates of the contribution of CaCO3 precipitation to the 2 release of CO2 to the atmosphere during young sea ice growth 3 N.-X. Geilfus(1,2,3,*), G. Carnat(3), G.S. Dieckmann(4), N. Halden(3), G. Nehrke(4), T. 4 Papakyriakou(3), J.-L. Tison(2) and B. Delille(1) 5 1. Unité d’Océanographie Chimique, Université de Liège, Allée du 6 aout, n°17, 4000 Liège, 6 Belgium. 7 2. Laboratoire de Glaciologie, D.S.T.E, Université Libre de Bruxelles, Av. F. D. Roosevelt, 8 1050 Bruxelles, CP 160/03, Belgium. 9 3. now at University of Manitoba, Center of Earth Observation Science, 470 Wallace Bldg, 10 125 Dysart Road, Winnipeg, Canada. 11 4. Biogeosciences, Alfred Wegener Institute for Polar and Marine Research, Am 12 Handelshafen 12, D-27570 Bremerhaven, Germany. 13 * Corresponding author: [email protected] 14 Abstract 15 We report measurements of pH, total alkalinity, air-ice CO2 fluxes (chamber method) and 16 CaCO3 content of frost flowers (FF) and thin landfast sea ice. As the temperature decreases, 17 concentration of solutes in the brine skim (BS) increases. Along this gradual concentration 18 process, some salts reach their solubility threshold and start precipitating. The precipitation of 19 ikaite (CaCO3.6H2O) was confirmed in the FF and throughout the ice by Raman spectroscopy 20 and X-ray analysis. The amount of ikaite precipitated was estimated to be 25 µmol kg-1 -1 -1 21 melted FF, in the FF and is shown to decrease from 19 µmol kg to 15 µmol kg melted ice 22 in the upper part and at the bottom of the ice, respectively.
    [Show full text]
  • Ice-Covered Regions in International Law
    Volume 31 Issue 1 The International Law of the Hydrologic Cycle Winter 1991 Ice-Covered Regions in International Law Christopher C. Joyner Recommended Citation Christopher C. Joyner, Ice-Covered Regions in International Law, 31 Nat. Resources J. 213 (1991). Available at: https://digitalrepository.unm.edu/nrj/vol31/iss1/11 This Article is brought to you for free and open access by the Law Journals at UNM Digital Repository. It has been accepted for inclusion in Natural Resources Journal by an authorized editor of UNM Digital Repository. For more information, please contact [email protected], [email protected], [email protected]. CHRISTOPHER C. JOYNER* Ice-Covered Regions in International Law ABSTRACT Permanent ice covers more than one-tenth of the earth's land surface, and seasonal ice covers one-tenth of the world's ocean surface. Yet, the internationallegal regimefor jurisdiction over ice remains incomplete and unclear. This is especially true in the Ant- arctic where serious legal questions persist over sovereign claims to that continent. This study examines various ice structures and aims to clarify their legal status. Ice forms analyzed include glacier ice, sea ice, shelf ice, icebergs, and ice islands. The conclusion of this study is obvious: As fresh water becomes more scarce, so too will exploitation of polar ice forms become more attractive. What is needed is more serious attention to fix the status of ice under inter- national law, such that its legal relationship with the rest of the earth's environment can be clearly established. I. INTRODUCTION Ice is the solid, crystalline form of water.
    [Show full text]
  • Ikaite (Caco3
    Papadimitriou et al.: Carbonic acid dissociation constants in brines at below-zero temperatures 1 The stoichiometric dissociation constants of carbonic acid in seawater brines from 298 to 2 267 K 3 4 Stathys Papadimitrioua,*, Socratis Loucaidesb, Victoire M. C. Rérolleb,1, Paul Kennedya, Eric P. 5 Achterbergc,2, Andrew G. Dicksond, Matthew Mowlemb, Hilary Kennedya 6 7 aOcean Sciences, College of Natural Sciences, Bangor University, Menai Bridge, Anglesey LL59 8 5AB, UK 9 bNational Oceanography Centre, Southampton, SO14 3ZH, UK 10 cUniversity of Southampton, National Oceanography Centre, Southampton, SO14 3ZH, UK 11 dMarine Physical Laboratory, Scripps Institution of Oceanography, University of California, San 12 Diego, 9500 Gilman Drive, La Jolla, CA 92093-0244, USA 13 14 1Present address: FLUIDION SAS, 75001 Paris, France 15 2Present address: GEOMAR, Helmholtz Centre for Ocean Research, 24148 Kiel, Germany 16 17 18 19 *Corresponding author: [email protected] (e-mail) 20 1 Papadimitriou et al.: Carbonic acid dissociation constants in brines at below-zero temperatures 21 Abstract * * 22 The stoichiometric dissociation constants of carbonic acid ( K1C and K 2C ) were determined 23 by measurement of all four measurable parameters of the carbonate system (total alkalinity, total 24 dissolved inorganic carbon, pH on the total proton scale, and CO2 fugacity) in natural seawater 25 and seawater-derived brines, with a major ion composition equivalent to that Reference Seawater, 26 to practical salinity (SP) 100 and from 25 °C to the freezing point of these solutions and –6 °C 27 temperature minimum. These values, reported in the total proton scale, provide the first such 28 determinations at below-zero temperatures and for SP > 50.
    [Show full text]
  • Xuelong Navigation in Fast Ice Near the Zhongshan Station, Antarctica
    PAPER Xuelong Navigation in Fast Ice Near the Zhongshan Station, Antarctica AUTHORS ABSTRACT Xianwei Wang Navigation in polar sea regions requires special attention to the sea ice condition State Key Laboratory of Remote because it is a major barrier for an icebreaker to break the drift ice or fast ice, allowing Sensing Science and College the vessel to keep moving forward. The advancement of remote sensing imagery pro- of Global Change and Earth vides an effective means to classify and identify various features, including different System Science, Beijing types of sea ice. Hence, it permits fuel and time saving for the entire voyage, especially Normal University, and when drift ice or fast ice becomes a barrier for the icebreaker. In this study, we exploit The Ohio State University the potential usage of high-resolution synthetic aperture radar (SAR) imageries from Xiao Cheng Radarsat-2 to identify sea ice conditions for precise navigation of China’s icebreaker Fengming Hui vessel (Xuelong) during the 29th Chinese Antarctic Research Expedition in December State Key Laboratory of Remote 2012. Different features on the fast ice were identified from horizontal-transmit and Sensing Science and College horizontal-receive polarized imagery. The potential usage of SAR imagery for precise of Global Change and Earth navigation was confirmed by an expert witness on the Xuelong vessel at that time. System Science, Beijing The final voyage route has validated our analysis of fast ice and navigation of the Normal University Xuelong vessel. The predicted regions for unloading locations were also found to be matching well with the actual vessel unloading locations after the final voyage route.
    [Show full text]
  • Observations: Changes in Snow, Ice and Frozen Ground
    4 Observations: Changes in Snow, Ice and Frozen Ground Coordinating Lead Authors: Peter Lemke (Germany), Jiawen Ren (China) Lead Authors: Richard B. Alley (USA), Ian Allison (Australia), Jorge Carrasco (Chile), Gregory Flato (Canada), Yoshiyuki Fujii (Japan), Georg Kaser (Austria, Italy), Philip Mote (USA), Robert H. Thomas (USA, Chile), Tingjun Zhang (USA, China) Contributing Authors: J. Box (USA), D. Bromwich (USA), R. Brown (Canada), J.G. Cogley (Canada), J. Comiso (USA), M. Dyurgerov (Sweden, USA), B. Fitzharris (New Zealand), O. Frauenfeld (USA, Austria), H. Fricker (USA), G. H. Gudmundsson (UK, Iceland), C. Haas (Germany), J.O. Hagen (Norway), C. Harris (UK), L. Hinzman (USA), R. Hock (Sweden), M. Hoelzle (Switzerland), P. Huybrechts (Belgium), K. Isaksen (Norway), P. Jansson (Sweden), A. Jenkins (UK), Ian Joughin (USA), C. Kottmeier (Germany), R. Kwok (USA), S. Laxon (UK), S. Liu (China), D. MacAyeal (USA), H. Melling (Canada), A. Ohmura (Switzerland), A. Payne (UK), T. Prowse (Canada), B.H. Raup (USA), C. Raymond (USA), E. Rignot (USA), I. Rigor (USA), D. Robinson (USA), D. Rothrock (USA), S.C. Scherrer (Switzerland), S. Smith (Canada), O. Solomina (Russian Federation), D. Vaughan (UK), J. Walsh (USA), A. Worby (Australia), T. Yamada (Japan), L. Zhao (China) Review Editors: Roger Barry (USA), Toshio Koike (Japan) This chapter should be cited as: Lemke, P., J. Ren, R.B. Alley, I. Allison, J. Carrasco, G. Flato, Y. Fujii, G. Kaser, P. Mote, R.H. Thomas and T. Zhang, 2007: Observations: Changes in Snow, Ice and Frozen Ground. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D.
    [Show full text]
  • Fine-Scale Sea-Ice Modelling of the Storfjorden Polynya, Svalbard
    Annals of Glaciology 44 2006 1 Fine-scale sea-ice modelling of the Storfjorden polynya, Svalbard Lars H. SMEDSRUD,1 W. Paul BUDGELL,1,2 Alastair D. JENKINS,1 Bjùrn AÊ DLANDSVIK1,2 1Bjerknes Centre for Climate Research, University of Bergen, Allegaten 70, NO-5007 Bergen, Norway E-mail: [email protected] 2Institute of Marine Research, PO Box 1870 Nordnes, NO-5817 Bergen, Norway ABSTRACT. A polynya appears regularly in Storfjorden on the east side of the Svalbard archipelago. It is mainly forced by offshore winds and contributes around 10% of the brine water produced on Arctic shelves. We have applied a regional ocean model (ROMS), including a sea-ice model, on a fine grid (2 km) to simulate a full year of sea-ice growth and decay starting on 1 August 1999. This allows us to reproduce some key processes of the polynya opening and closing events during January±April 2000. The polynya remains open as long as the offshore winds exist, and reaches a width along the direction of the wind of 10±20 km. We suggest using a mean sea-ice thickness of <0.3 m as the polynya criterion, as our simulations show varying strength in the horizontal gradients in sea-ice concentration and thickness. Results show a general freeze-up during December and January, with a mean polynya area during February±April within the fjord of 33 by 50 km, being 13% of the total fjord area. Some model results including sea-ice cover and drift speed can be partially validated using satellite imagery and field data, but in general are new measurements from the polynya interior needed to further improve the modelling of solid- and grease-ice processes.
    [Show full text]
  • Resolving Fine-Scale Surface Features on Polar Sea Ice: a First Assessment of UAS Photogrammetry Without Ground Control
    remote sensing Article Resolving Fine-Scale Surface Features on Polar Sea Ice: A First Assessment of UAS Photogrammetry Without Ground Control Teng Li 1,2,3,4, Baogang Zhang 1,3,4, Xiao Cheng 1,3,4,*, Matthew J. Westoby 2, Zhenhong Li 5, Chi Ma 1,3, Fengming Hui 1,3,4, Mohammed Shokr 6, Yan Liu 1,3,4, Zhuoqi Chen 1,3,4, Mengxi Zhai 1,3,4 and Xinqing Li 1,3,4 1 State Key Laboratory of Remote Sensing Science, College of Global Change and Earth System Science (GCESS), Beijing Normal University, Beijing 100875, China; [email protected] (T.L.); [email protected] (B.Z); [email protected] (C.M.); [email protected] (F.H.); [email protected] (Y.L.); [email protected] (Z.C.); [email protected] (M.Z); [email protected] (X.L.); 2 Department of Geography, Engineering and Environment, Northumbria University, Newcastle upon Tyne NE1 8ST, UK; [email protected] 3 Joint Center for Global Change Studies (JCGCS), Beijing 100875, China 4 University Corporation for Polar Research (UCPR), Beijing 100875, China 5 School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; [email protected] 6 Science and Technology Branch, Environment Canada, Toronto, ON M3H5T4, Canada; [email protected] * Correspondence: [email protected] Received: 17 February 2019; Accepted: 30 March 2019; Published: 1 April 2019 Abstract: Mapping landfast sea ice at a fine spatial scale is not only meaningful for geophysical study, but is also of benefit for providing information about human activities upon it.
    [Show full text]