HR: 1340h
AN: C33B-1125    [Abstracts]
TI: Variations in melt conditions in the Arctic through use of surface energy proxy
AU: Anderson, M R
EM: mra@unl.edu
AF: University of Nebraska - Lincoln, 214 Bessey Hall, Lincoln, NE 68588-0340 United States
AU: * Jackson, B A
EM: jacksonb@bigred.unl.edu
AF: University of Nebraska - Lincoln, 214 Bessey Hall, Lincoln, NE 68588-0340 United States
AB: The Arctic Ocean is an integral part of the global climate system and an area that is forecasted to exhibit seasonal fluctuations due to climate change. This study investigates changes in the Arctic sea ice cover from 1979 to 2004 through a surface energy budget proxy, melting degree days (MDD). The MDD is calculated from NCEP/NCAR reanalysis temperature records between the date of melt onset and the ice reduction date. The ice reduction date is when the ice concentration drops below 80 percent. Both the melt onset and ice reduction dates are derived from passive microwave remote sensing. There is a notable period of time, delta t, between the melt onset and ice reduction. Analysis of delta t for the Arctic over the microwave record provides explanations for changes in sea ice cover over time. For instance, an anomalously short delta t could be an outcome of an atmospheric pattern that brings unseasonably warm temperatures to the region, reducing the ice concentrations. However, the same delta t could be a result of thinner ice melting in the same time period with less warm air advection. Understanding the surface energy budget could be used to determine why patterns in ice concentration and extent occur during certain years, but not for others. Therefore, the MDD is used as a proxy to the amount of energy available for melt. Variations in the MDD are given for the region to explain recent changes in the ice conditions.
DE: 0700 CRYOSPHERE (4540)
DE: 0740 Snowmelt
DE: 0750 Sea ice (4540)
DE: 0758 Remote sensing
DE: 0764 Energy balance
SC: Cryosphere [C]
MN: Fall Meeting 2005