HR: 14:10h
AN: U33B-03    [Abstracts]
TI: Arctic Sea Ice Conditions Leading to Record Reduction in Summer 2007
AU: * Nghiem, S V
EM: Son.V.Nghiem@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, MS 300-235, Pasadena, CA 91109, United States
AU: Rigor, I G
EM: ignatius@apl.washington.edu
AF: Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, WA 98105, United States
AU: Perovich, D K
EM: Donald.K.Perovich@erdc.usace.army.mil
AF: U.S. Army Cold Regions Research and Engineering Laboratory, 72 Lyme Road, Hanover, NH 03755, United States
AU: Clemente-Colon, P
EM: Pablo.Clemente-Colon@natice.noaa.gov
AF: National Ice Center, 4251 Suitland Road, Washington, DC 20935, United States
AU: Weatherly, J W
EM: John.W.Weatherly@erdc.usace.army.mil
AF: U.S. Army Cold Regions Research and Engineering Laboratory, 72 Lyme Road, Hanover, NH 03755, United States
AU: Neumann, G
EM: Gregory.Neumann@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, MS 300-235, Pasadena, CA 91109, United States
AB: Drastic reduction of Arctic sea ice has been occurring in the summer of 2007 as observed from data acquired by the QuikSCAT/SeaWinds satellite scatterometer (QSCAT). As of 24 August 2007, the total sea ice extent broke the record-low value set in September 2005; however, the difference of 0.02 million km² was still within the satellite measurement uncertainty. On 28 August 2007, the total ice extent was lower than the September-2005 minimum by 0.22 million km², which was larger than the uncertainty in QSCAT results. The rate of decrease of total ice extent from the summer solstice (21 June) to 9 August was the largest in 2007, which was 23% more rapid than the rate over the same time period in 2005. We will update the results as the latest data become available. Most importantly, we present the change in Arctic sea ice conditions causing such drastic ice reduction. The extent of Arctic perennial sea ice was significantly reduced between March 2005 and March 2007 by 1.08 million km², a 23% loss between the two years, as observed by QSCAT. Consequently, the overall Arctic sea ice pack consisted more of the thinner seasonal ice, which would facilitate ice compression, export, and melt in summer. For a long-term perspective, the buoy-based Drift-Age Model (DM) has provided trends in Arctic sea ice age over the past five decades. Perennial-ice extent loss in March within the DM domain was noticeable after the 1960s, and the loss became more rapid in the 2000s when QSCAT observations were available to verify the DM results. The end-of-winter extent of perennial ice was the smallest on record in March 2007. QSCAT results also revealed mechanisms contributing to the perennial-ice extent loss. Dynamic and thermodynamic effects appear to be combining to expedite the loss of sea ice.
DE: 0750 Sea ice (4540)
DE: 0758 Remote sensing
DE: 0762 Mass balance (1218, 1223)
DE: 0774 Dynamics
DE: 0798 Modeling
SC: Union [U]
MN: 2007 Fall Meeting