HR: 1330h
AN: C43A-06    [Abstracts]
TI: Changes of Arctic Sea Ice and Their Attribution: Multi-model Investigations in the IPCC AR4 Framework
AU: * Zhang, X
EM: xdz@iarc.uaf.edu
AF: International Arctic Research Center, University of Alaska Fairbanks, 930 Koyukuk Dr., Fairbanks, AK 99775 United States
AB: Sea ice is an essential component of cryosphere, which is active on relatively short time scales compared to some other cryospheric components and obviously interacts with other parts of climate system. Sea ice has been recognized as an integrative indicator of global climate change. Recent dramatic shrinking of Arctic sea ice cover has drawn much attention scientifically and socially. Amplified global warming in the polar region may result in a further rapid decrease of sea ice cover, leading to an ice-free summer in the Arctic Ocean in future, as projected in global warming scenarios. The changes of sea ice may naturally cause significant climatic consequences by changing the energy budgets and hydrological cycle and altering atmospheric circulation regimes. Moreover, changes of sea ice exports may also affect the North Atlantic deep convections and Meridional Overturning Circulation, which is associated with multidecadal climate variability. In this study, we analyze changes of sea ice cover and volume based on the multiple model outputs for IPCC AR4 (Intergovernmental Panel on Climate Change, the 4th Assessment Report), archived by PCMDI (Program for Climate Model Diagnosis and Intercomparison). We first examined the Arctic sea ice simulations for the climate of 20th century (20C3M) and validated model's performance. Considering availability of accurate sea ice observations by satellites, we selected a period of 1979-99 from ensemble means of each model's experiments and compared model results with observational data. Then, we investigated changes of sea ice extend, area and volume in the 20th century and in the 21st century under global warming scenarios (SRES A1b, SRES A2, and SRES B1) among various participating climate models and explored their attributions.
DE: 1600 GLOBAL CHANGE (New category)
DE: 1620 Climate dynamics (3309)
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 4207 Arctic and Antarctic oceanography
DE: 4540 Ice mechanics and air/sea/ice exchange processes
SC: Cryosphere [C]
MN: 2005 Joint Assembly