The Antarctic's Ice Paradox | PBS Newshour

Total Page:16

File Type:pdf, Size:1020Kb

The Antarctic's Ice Paradox | PBS Newshour 5/2/13 The Antarctic's Ice Paradox | PBS NewsHour SCIENCE WEDNESDAY -- May 1, 2013 at 5:34 PM EDT The Antarctic's Ice Paradox BY: REBECCA JA COBSON Like 16 Scientists have been trying to create a clearer picture of how the Antarctic responds to climate change. Photo by Nerilie Abram. It's no secret that the ice sheet is melting in Greenland. Last year, the Arctic ice cap shrunk to a record low, with only 24 percent of the Arctic Ocean covered by ice, a 50 percent drop from its 1979-2000 summer average. At the height of the 2012 summer, Greenland had experienced melting across 90 percent of its surface. For a journalist, it's an easy story to tell: temperatures climb, the ice shrinks. But at the opposite end of the world, in Antarctica, the picture isn't quite as clear. Satellite images from 2012 showed that Antarctic sea ice reached its highest levels extent on record, evidence skeptics often point to as proof that climate change isn't happening. And for years, the East Antarctic ice sheet, which covers the majority of the continent, appeared to be stable or perhaps even gaining mass. www.pbs.org/newshour/rundown/2013/05/why-climate-change-means-more----and-less----ice-for-the-antarctic.html 1/4 5/2/13 The Antarctic's Ice Paradox | PBS NewsHour Sea ice around Antarctica, June 21, 2012. Although average sea ice extents around Antarctica have been increasing over the last several years, land-based ice sheets are melting at fast rates. Courtesy NOAA. There are several reasons why changes in Antarctica are simply harder to explain than those in the Arctic, says Waleed Abdalati, professor of geography at the University of Colorado. The geography is different and data collection is challenging, he said. Plus, the climate and a large hole in the ozone layer have buffered large parts of the continent from warmer air. "The fact that you have a large, tall, thick ice sheet situated at the South Pole creates a climate down there that tends to isolate it from the rest of the world," Abdalati said. "And it does that in large part by setting up a circulation pattern where winds blow around the perimeter of the continent and block warmer air from lower latitudes." Unlike the Arctic, it has been almost impossible at times to collect data in Antarctica. Satellite data only dates back to 1979; research station data to the mid-1950s, in some areas. The ice sheet east of the Transantarctic mountains was less explored and less understood until recently; parts are still inaccessible. And throughout the continent, which is larger than the United States, the ice sheet varies dramatically, making the ice losses and gains more difficult to tease out, Abdalati said. Greenland, on the other hand is smaller, easier to access and has been therefore studied in greater detail. So what is really happening in the Antarctic? The short answer is that the ice around Antarctica is growing, but the ice on the continent is shrinking, and both are a result of climate change. Just how much it's changing and how fast depends on where you look. In some parts of the continent, the Antarctic ice is melting just as rapidly as the ice in the Arctic Circle. In fact, the Antarctic peninsula, which juts into the Southern Ocean, was one of the earliest climate change "hot spots", where rapid warming caused enormous segments of glaciers to break off into the ocean. In a recent study in the journal Nature Geoscience, new ice core data from James Ross Island, located at the northern tip of the peninsula, shows that warming on the peninsula has reached its www.pbs.org/newshour/rundown/2013/05/why-climate-change-means-more----and-less----ice-for-the-antarctic.html 2/4 5/2/13 The Antarctic's Ice Paradox | PBS NewsHour highest rate in 1,000 years. Nerilie Abram works with ice core samples from Antarctica. Photo by Paul Rogers. Nerilie Abram, a research fellow at Australian National University and lead author of the study said that the ice melt in peninsula has increased 10-fold over the last 600 years, with the largest increases occurring in the last half century. "The Antarctic peninsula contributes to more than half of the ice melt in Antarctica, and even there it varies," Abram said. "On James Ross Island, almost 5 percent of the ice cap is melting and refreezing. But if you went down to the coastal areas that are at sea level around island, the amount of melt is even higher." The peninsula is particularly vulnerable because of its location in the Southern Ocean, which has a warming effect, she added. At the West Antarctic ice sheet, ice is melting faster than it ever has in that location, but at a less dramatic pace than on the peninsula, said Eric Steig of the University of Washington, whose study was also published recently in Nature Geoscience. There, warmer air temperatures combined with warmer ocean water circulating below the ice shelves both cause the ice to melt at the "upper bound of normal," he said. At this rate of melt, the ice shelves in Antarctica won't last, he explains, and its not obviously linked to human activity the way it is on the peninsula. And of course, that rate could change. He suspects that the melt on the West Antarctic ice sheet is similar to what occurred on the peninsula 20 years ago, Steig said. And while the ice loss has been fairly well documented in the west and the peninsula, data on the East Antarctic ice sheet paints a murkier picture. The most recent estimate published in the journal Science in 2012 states that the East Antarctic ice sheet is gaining mass by 14 gigatonnes per year. However, that data, as the study points out, has a 43 gigaton margin of error, Abdalati says, making it difficult to confirm the gain with any certainty. Perhaps the most confusing detail - the growth of sea ice around Antarctica - is also a direct response www.pbs.org/newshour/rundown/2013/05/why-climate-change-means-more----and-less----ice-for-the-antarctic.html 3/4 5/2/13 The Antarctic's Ice Paradox | PBS NewsHour to climate change, said Andrew Carleton, professor of physical geography at Penn State University. Despite the warming climate, sea ice surrounding the continent has increased about one percent every decade between 1979 and 2008, according to the National Snow and Ice Data Center. It seems counter intuitive, but that growth is a result of the glacial melt happening on the rest of the continent, Carleton said. As fresh water melts into the ocean it decreases the salinity of the seawater, he explained. Water with less salt content freezes at a higher temperature, so even with warming air temperatures melting the glaciers, the Antarctic Ocean continues to gain sea ice. "It seems paradoxical, but it makes sense," Carleton said. The story of Antarctica is not a simple one, Abdalati says, and scientists are still working to make sense of how it fits in the bigger picture of climate change. "It's not that it doesn't fit. It all fits," he said. "We have to ask 'what is the story telling us?'" MAKE A COMMENT ( 4 ) RETWEET FACEBOOK EMAIL SHARE www.pbs.org/newshour/rundown/2013/05/why-climate-change-means-more----and-less----ice-for-the-antarctic.html 4/4.
Recommended publications
  • Antarctic Climate and Sea Ice Variability – a Brief Review Marilyn Raphael UCLA Geography
    Antarctic Climate and Sea Ice Variability – a Brief Review Marilyn Raphael UCLA Geography WRCP Workshop on Seasonal to Multi- Decadal Predictability of Polar Climate Mean annual precipitation produced by NCEP2 for the years 1979–99 (mm yr21water equivalent). Bromwich et al, 2004 A significant upward trend 11.3 to 11.7 mm yr22 for 1979–99 is found from retrieved and forecast Antarctic precipitation over the continent. (a) Monthly and (b) annual time series for the modeled precipitation over all of Antarctica. Bromwich et al, 2004 Spatial pattern of temperature trends (degrees Celsius per decade) from reconstruction using infrared (TIR) satellite data. a, Mean annual trends for 1957–2006; b, Mean annual trends for 1969–2000, c–f, Seasonal trends for 1957–2006: winter (June, July, August; c); spring (September, October, November; d); summer (December, January, February; e); autumn (March, April, May; f). Over the long term (150 years) Antarctica has been warming, recent cooling trends in the 1990s attributed to positive trend in the SAM offset this warming. (Schneider et al, 2006) – ice cores Warming of Antarctica extends beyond the Antarctic Peninsula includes most of west Antarctica. Except in autumn, warming is apparent across most of the continent but is significant only over west Antarctica including the Peninsula (Steig et al, 2009). 1957 – 2006 reconstruction from satellite data. Steig et al, 2009 Steig et al, 2009 – reconstruction based on satellite and station data annual warming of 0.18C per decade for 1957 – 2006; winter and spring leading. Chapman and Walsh, 2007 – reconstruction based on station data and oceanic records 1950-2002: warming across most of West Antarctica Monaghan et al, 2009 – reconstruction 190-2005: warming across West Antarctica in all seasons; significant in spring and summer Trends are strongly seasonal.
    [Show full text]
  • 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]
  • Mid-Holocene Antarctic Sea-Ice Increase Driven by Marine Ice Sheet Retreat
    https://doi.org/10.5194/cp-2020-3 Preprint. Discussion started: 26 February 2020 c Author(s) 2020. CC BY 4.0 License. 1 FRONT MATTER 2 Title 3 Mid-Holocene Antarctic sea-ice increase driven by marine ice sheet retreat 4 Authors 5 Kate E. Ashley1*, James A. Bendle1, Robert McKay2, Johan Etourneau3, Francis J. Jimenez-Espejo3,4, 6 Alan Condron5, Anna Albot2, Xavier Crosta6, Christina Riesselman7,8, Osamu Seki9, Guillaume Massé10, 7 Nicholas R. Golledge2,11, Edward Gasson12, Daniel P. Lowry2, Nicholas E. Barrand1, Katelyn Johnson2, 8 Nancy Bertler2, Carlota Escutia3 and Robert Dunbar13. 9 Affiliations 10 1School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, 11 Birmingham, B15 2TT, UK 12 2Antarctic Research Centre, Victoria University of Wellington, Wellington 6140, New Zealand 13 3Instituto Andaluz de Ciencias de la Tierra (CSIC), Avenida de las Palmeras 4, 18100 Armilla, Granada, 14 Spain 15 4Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology 16 (JAMSTEC), Yokosuka 237-0061, Japan 17 5Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 18 02543, USA 19 6UMR-CNRS 5805 EPOC, Université de Bordeaux, 33615 Pessac, France 20 7Department of Geology, University of Otago, Dunedin 9016, New Zealand 21 8Department of Marine Science, University of Otago, Dunedin 9016, New Zealand 22 9Institite of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido, Japan 23 10TAKUVIK, UMI 3376 UL/CNRS, Université Laval, 1045 avenue de la Médecine, Quebec City, 24 Quebec, Canada G1V 0A6 25 11GNS Science, Avalon, Lower Hutt 5011, New Zealand 26 12Department of Geography, University of Sheffield, Winter Street, Sheffield, S10 2TN, UK 27 13Department of Environmental Earth Systems Science, Stanford University, Stanford, A 94305-2115 28 29 *Corresponding Author: email: [email protected] Climate of The Past Ashley et al., 2019 Submitted Manuscript Page 1 of 36 https://doi.org/10.5194/cp-2020-3 Preprint.
    [Show full text]
  • Sea-Floor and Sea-Ice Conditions in the Western Weddell Sea, Antarctica, Around the Wreck of Sir Ernest Shackleton’S Endurance
    Sea-floor and sea-ice conditions in the western Weddell Sea, Antarctica, around the wreck of Sir Ernest Shackleton’s Endurance J.A. Dowdeswell a, C.L. Batchelor a,b, B. Dorschel c, T.J. Benham a, F.D.W. Christie a, E.K. Dowdeswell a, A. Montelli a, J.E. Arndt c, C. Gebhardt c a Scott Polar Research Institute, University of Cambridge, Cambridge CB2 1ER, UK b Norwegian University of Science and Technology (NTNU), NO-7491, Trondheim, Norway c Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany Abstract: Marine-geophysical evidence on sea-floor morphology and shallow acoustic stratigraphy is used to examine the substrate around the location at which Sir Ernest Shackleton’s ship Endurance sank in 1915 and on the continental slope-shelf sedimentary system above this site in the western Weddell Sea. Few signs of turbidity-current and mass- wasting activity are found near or upslope of the wreck site, and any such activity was probably linked to full-glacial higher-energy conditions when ice last advanced across the continental shelf. The wreck is well below the maximum depth of iceberg keels and will not have been damaged by ice-keel ploughing. The wreck has probably been draped by only a few centimetres of fine-grained sediment since it sank in 1915. Severe modern sea-ice conditions hamper access to the wreck site. Accessing and investigating the wreck of Endurance in the Weddell Sea therefore represents a significant challenge. An ice-breaking research vessel is required and even this would not guarantee that the site could be reached.
    [Show full text]
  • Environmental Geology
    Environ Geol DOI 10.1007/s00254-008-1393-y VIEWS AND NEWS International viewpoint and news Ó Springer-Verlag 2008 Global interagency IPY polar snapshot year: an update most significant technical advances since the IGY. To realize the benefit of the growing constellation of interna- Kenneth Jezek and Mark R. Drinkwater tional satellites to the IPY, the Global Interagency IPY Polar Snapshot Year (GIIPSY) proposal was selected as an IPY Dramatic changes in Earth’s ice covered regions are flagship project. The goal of GIIPSY is to develop consensus sparking new and vigorous scientific interest in these polar science requirements and objectives that can best and remote parts of the world. Observations of record reduc- perhaps only be met using the international constellation of tions in Arctic summer sea ice extent, the loss of Antarctic earth observing satellites. Requirements focus on all aspects Peninsula ice shelves and rapid thinning of glaciers and ice of the cryosphere and range from sea ice to permafrost to caps around the world raise concern about changing cli- glaciers and ice sheets. Individual topics include develop- mate and the attendant societal impacts including global ment of high resolution digital elevation models of outlet sea level rise. Partly in response to these observations and glaciers using stereo optical systems, measurements of ice partly as a continuation of the heritage of polar scientific surface velocity using interferometric synthetic aperture observations, the International Council for Scientific radar (SAR/InSAR), and frequently repeated measurements Unions established an International Polar Year (IPY) of sea ice motion using medium resolution optical and 2007–2008.
    [Show full text]
  • A 200 Year Sulfate Record from Sixteen Antarctic Ice Cores and Associations with Southern Ocean Sea-Ice Extent D
    The University of Maine DigitalCommons@UMaine Earth Science Faculty Scholarship Earth Sciences 2005 A 200 Year Sulfate Record from Sixteen Antarctic Ice Cores and Associations With Southern Ocean Sea-Ice Extent D. Dixon Paul Andrew Mayewski University of Maine - Main, [email protected] S. Kaspari Karl J. Kreutz University of Maine - Main, [email protected] Gordon S. Hamilton University of Maine - Main, [email protected] See next page for additional authors Follow this and additional works at: https://digitalcommons.library.umaine.edu/ers_facpub Part of the Earth Sciences Commons Repository Citation Dixon, D.; Mayewski, Paul Andrew; Kaspari, S.; Kreutz, Karl J.; Hamilton, Gordon S.; Maasch, Kirk A.; Sneed, Sharon B.; and Handley, M. J., "A 200 Year Sulfate Record from Sixteen Antarctic Ice Cores and Associations With Southern Ocean Sea-Ice Extent" (2005). Earth Science Faculty Scholarship. 121. https://digitalcommons.library.umaine.edu/ers_facpub/121 This Conference Proceeding is brought to you for free and open access by DigitalCommons@UMaine. It has been accepted for inclusion in Earth Science Faculty Scholarship by an authorized administrator of DigitalCommons@UMaine. For more information, please contact [email protected]. Authors D. Dixon, Paul Andrew Mayewski, S. Kaspari, Karl J. Kreutz, Gordon S. Hamilton, Kirk A. Maasch, Sharon B. Sneed, and M. J. Handley This conference proceeding is available at DigitalCommons@UMaine: https://digitalcommons.library.umaine.edu/ers_facpub/121 Annals of Glaciology 41 2005 155 A 200 year sulfate record from 16 Antarctic ice cores and associations with Southern Ocean sea-ice extent Daniel DIXON, Paul A. MAYEWSKI, Susan KASPARI, Karl KREUTZ, Gordon HAMILTON, Kirk MAASCH, Sharon B.
    [Show full text]
  • Unexpected Ice
    Unexpected ice “I always thought, and as far as by Natasha Vizcarra sunlight, and food—they all come and go with I can tell everyone else thought, the seasons in the Southern Ocean. On the prowl for food, Adelie penguins scan the that the biggest changes must ice ceiling. They peck at silverfish and hunt for Paul Holland, a climate modeler with the British be in autumn.” polynyas, gaping holes in the sea ice where shoals Antarctic Survey, has spent the last ten years of krill and bug-like copepods graze on clouds of studying Antarctica’s sea ice and the Southern Paul Holland algae. When spring comes, the huge plates of sea Ocean. Lately, he has been scrutinizing the British Antarctic Survey ice start to melt and later in the brief Antarctic seasons of Antarctica and how fast the ice comes summer all but disappear. Then, algae blooms and goes. Holland thinks these seasons may be a unfurl: a bacchanalian feast for krill and critters key to a conundrum: If Earth’s temperatures are all the way up the Antarctic food chain. Sea ice, getting warmer and sea ice in the Arctic has been A pressure ridge forms on the sea ice near Scott Base in Antarctica. These form when separate ice floes collide and pile up on each other. Lenticular clouds are seen above. (Courtesy M. Studinger/NASA) 28 shrinking fast, why then is sea ice in the Antarc- “The Antarctic case is as interesting as the Arctic tic slowly increasing? case,” Holland said. “You can’t understand one without understanding the other.” Opposite poles Minding the models Sea ice is simply frozen seawater.
    [Show full text]
  • Estimating the Extent of Antarctic Summer Sea Ice During the Heroic Age of Antarctic Exploration
    Estimating the extent of Antarctic summer sea ice during the Heroic Age of Antarctic Exploration Article Published Version Creative Commons: Attribution 3.0 (CC-BY) Open Access Edinburgh, T. and Day, J. J. (2016) Estimating the extent of Antarctic summer sea ice during the Heroic Age of Antarctic Exploration. The Cryosphere, 10 (6). pp. 2721-2730. ISSN 1994-0424 doi: https://doi.org/10.5194/tc-10-2721-2016 Available at http://centaur.reading.ac.uk/68171/ It is advisable to refer to the publisher’s version if you intend to cite from the work. See Guidance on citing . To link to this article DOI: http://dx.doi.org/10.5194/tc-10-2721-2016 Publisher: European Geosciences Union All outputs in CentAUR are protected by Intellectual Property Rights law, including copyright law. Copyright and IPR is retained by the creators or other copyright holders. Terms and conditions for use of this material are defined in the End User Agreement . www.reading.ac.uk/centaur CentAUR Central Archive at the University of Reading Reading’s research outputs online The Cryosphere, 10, 2721–2730, 2016 www.the-cryosphere.net/10/2721/2016/ doi:10.5194/tc-10-2721-2016 © Author(s) 2016. CC Attribution 3.0 License. Estimating the extent of Antarctic summer sea ice during the Heroic Age of Antarctic Exploration Tom Edinburgh1,a and Jonathan J. Day1 1Department of Meteorology, University of Reading, Reading, UK acurrently at: Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK Correspondence to: Jonathan J. Day ([email protected]) Received: 13 April 2016 – Published in The Cryosphere Discuss.: 29 April 2016 Revised: 11 September 2016 – Accepted: 18 September 2016 – Published: 21 November 2016 Abstract.
    [Show full text]
  • Sea Lee Lnvestigation in the Weddell Sea
    Polarjorschung 51 (1): 21-37, 1981 Sea lee lnvestigation in the Weddell Sea By Joachim Schwarz' Summary: During the German Antarctic Expedition 1979/80, the sea ice conditions in the Weddell Sea were studied along the ice shelf bet­ ween Cape Fiske (root of the Antarctlc Peninsula) and Atka Bay. Most intensively was the sea ice investigated in an area about 100 km northwest of Berkner Island, where a suitable site for the German station was found. In addition to the drift conditions, ice thickness as weIl as temoerature and salinity of the ice were measured and the mechanical properties established. Several ice co res were taken back to Germany, where the compressive strength was measured in respect to strain rate, salinity, depth and temperature. Zusammenfassung: Während der Deutschen Antarktis-Expedition 1979/80 wurde das Meereis in der Weddell-See entlang der Schelfeiskante von Kap Fiske (Wurzel der Antarktischen Halbinsel) bis zur Atka-Bucht mit einem Schwerpunkt in einem Gebiet rd. 100 km nordwestlich der Berkner-Insel untersucht. Zusätzlich zu den Driftverhältnissen des Eises wurden die Eisdicke, die Eistemperatur sowie der Salzgehalt im Eis gemessen und die mechanischen Eigenschaften des Eises ermittelt. Einige Einbohrkerne wurden mit nach Deutschland genommen, wo die Druckfestigkeit in Abhängigkeit von der Belastungsrate. vom Salzge. halt, von der Temperatur und der Tiefe im Eis gemessen wurde. 1. INTRODUCTION From December 1979 till March 1980 the Federal Republic of Germany carried out an Antarctic Expedi­ tion in order to search out a suitable site on the Filchner/Ronne Shelf for the German Antarctic station to be constructed in 1980/81.
    [Show full text]
  • Ice Sheet Record of Recent Polynya Variability In
    JOURNAL OF GEOPHYSICAL RESEARCH: OCEANS, VOL. 118, 1–13, doi:10.1029/2012JC008077, 2013 Ice sheet record of recent sea-ice behavior and polynya variability in the Amundsen Sea, West Antarctica Alison S. Criscitiello,1,2 Sarah B. Das,2 Matthew J. Evans,3 Karen E. Frey,4 Howard Conway,5 Ian Joughin,5,6 Brooke Medley,5 and Eric J. Steig5,7 Received 22 March 2012; revised 26 October 2012; accepted 3 November 2012. [1] Our understanding of past sea-ice variability is limited by the short length of satellite and instrumental records. Proxy records can extend these observations but require further development and validation. We compare methanesulfonic acid (MSA) and chloride (Cl–) concentrations from a new firn core from coastal West Antarctica with satellite-derived observations of regional sea-ice concentration (SIC) in the Amundsen Sea (AS) to evaluate spatial and temporal correlations from 2002–2010. The high accumulation rate (~39 g∙cm–2∙yr–1) provides monthly resolved records of MSA and Cl–, allowing detailed investigation of how regional SIC is recorded in the ice-sheet stratigraphy. Over the period 2002–2010 we find that the ice-sheet chemistry is significantly correlated with SIC variability within the AS and Pine Island Bay polynyas. Based on this result, we evaluate the use of ice- core chemistry as a proxy for interannual polynya variability in this region, one of the largest and most persistent polynya areas in Antarctica. MSA concentrations correlate strongly with summer SIC within the polynya regions, consistent with MSA at this site being derived from marine biological productivity during the spring and summer.
    [Show full text]
  • Arctic Report Card 2020 the Sustained Transformation to a Warmer, Less Frozen and Biologically Changed Arctic Remains Clear
    Arctic Report Card 2020 The sustained transformation to a warmer, less frozen and biologically changed Arctic remains clear DOI: 10.25923/MN5P-T549X R.L. Thoman, J. Richter-Menge, and M.L. Druckenmiller; Eds. December 2020 Richard L. Thoman, Jacqueline Richter-Menge, and Matthew L. Druckenmiller; Editors Benjamin J. DeAngelo; NOAA Executive Editor Kelley A. Uhlig; NOAA Coordinating Editor www.arctic.noaa.gov/Report-Card How to Cite Arctic Report Card 2020 Citing the complete report or Executive Summary: Thoman, R. L., J. Richter-Menge, and M. L. Druckenmiller, Eds., 2020: Arctic Report Card 2020, https://doi.org/10.25923/mn5p-t549. Citing an essay (example): Frey, K. E., J. C. Comiso, L. W. Cooper, J. M. Grebmeier, and L. V. Stock, 2020: Arctic Ocean primary productivity: The response of marine algae to climate warming and sea ice decline. Arctic Report Card 2020, R. L. Thoman, J. Richter-Menge, and M. L. Druckenmiller, Eds., https://doi.org/10.25923/vtdn-2198. (Note: Each essay has a unique DOI assigned) Front cover photo credits Center: Yamal Peninsula wildland fire, Siberia, 2017 – Jeffrey T. Kerby, National Geographic Society, Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark Top Left: Large blocks of ice-rich permafrost fall onto the beach along the Laptev Sea coast, Siberia, 2017 – Pier Paul Overduin, Alfred Wegner Institute for Polar and Marine Research, Potsdam, Germany Top Right: R/V Polarstern during polar night, MOSAiC Expedition, 2019 – Matthew Shupe, Cooperative Institute for Research in Environmental Sciences, University of Colorado and NOAA Physical Sciences Laboratory, Boulder, Colorado, USA Mention of a commercial company or product does not constitute an endorsement by NOAA/OAR.
    [Show full text]
  • Polynyas in the Southern Ocean They Are Vast Gaps in the Sea Ice Around Antarctica
    Polynyas in the Southern Ocean They are vast gaps in the sea ice around Antarctica. By exposing enormous areas of seawater to the frigid air, they help to drive the global heat engine that couples the ocean and the atmosphere by Arnold L. Gordon and Josefino C. (omiso uring the austral winter (the In these regions, called polynyas, the largest and longest-lived polynyas. It months between June and Sep­ surface waters of the Southern Ocean is not yet fully understood what forces Dtember) as much as 20 million (the ocean surrounding Antarctica) are create and sustain open-ocean polyn­ square kilometers of ocean surround­ bared to the frigid polar atmosphere. yas, but ship and satellite data gath­ ing Antarctica-an area about twice Polynyas and their effects are only ered by us and by other investigators the size of the continental U.S.-is cov­ incompletely understood, but it now are enabling oceanographers to devise ered by ice. For more than two cen­ appears they are both a result of the reasonable hypotheses. turies, beginning with the voyages of dramatic interaction of ocean and at­ Captain James Cook in the late 18th mosphere that takes place in the Ant­ n order to understand the specific century, explorers, whalers and scien­ arctic and a major participant in it. forces that create and sustain po­ tists charted the outer fringes of the The exchanges of energy, water and Ilynyas and the effects polynyas can ice pack from on board ship. Never­ gases between the ocean and the at­ have, one must first understand the theless, except for reports from the mosphere around Antarctica have a role the Southern Ocean plays in the few ships that survived after being major role in determining the large­ general circulation of the world ocean trapped in the pack ice, not much was scale motion, temperature and chemi­ and in the global climate as a whole.
    [Show full text]