HR: 1340h
AN: C23A-1157    [Abstracts]
TI: Response of Alaska Glaciers to Global Warming: an Atmospheric / Glacier Mass Balance Modeling Approach
AU: Lingle, C S
EM: clingle@gi.alaska.edu
AF: Geophysical Institute University of Alaska Fairbanks, 903 Koyukuk Dr. , Fairbanks, AK 99775-7320 United States
AU: * Zhang, J
EM: jing@gi.alaska.edu
AF: Geophysical Institute University of Alaska Fairbanks, 903 Koyukuk Dr. , Fairbanks, AK 99775-7320 United States
AU: Bhatt, U S
EM: bhatt@gi.alaska.edu
AF: Geophysical Institute University of Alaska Fairbanks, 903 Koyukuk Dr. , Fairbanks, AK 99775-7320 United States
AU: Tangnorn, W
EM: hymetco@centurytel.net
AF: Hymet, Inc., 19001 Vashon Hwy SW Suite 201, Vashon, WA 98070 United States
AB: Airborne laser altimeter / coupled kinematic GPS measurements have shown rapid ice loss from glaciers in Alaska, Yukon, and NW British Columbia. Thinning and retreat of these ice masses accounted for approximately 8 to 12% of observed global mean sea-level rise during the mid-1950's to 2000/'01 (Arendt et al., 2002). This is much larger than previously-estimated ice loss from these glaciers and was, at that time, the largest measured glaciological contribution from a single source region to rising sea level. It is likely to be attributable to the strongest land warming in the past millennia in northern high latitudes, as demonstrated by observations (e.g.,IPCC, 2001). If global warming continues as projected by the most recent IPCC AR4 climate model simulations, thinning and retreat of these glaciers, as well as other mountain glaciers world-wide, is likely to accelerate. Our study addresses the problem of quantitatively estimating the response of the glaciers of NW North America to continued climatic warming, and hence their future contribution to rising sea level. To address this problem, we employ an Arctic regional model (MM5) driven by the NCAR Community Climate System Model (CCSM3), in conjunction with a glacier precipitation temperature-area-altitude (PTAA) mass balance model(Tangborn, 1998), to estimate climate-forced changes in glacier mass balance. CSM future scenario A2B (moderate) is employed to force the Arctic MM5. Modeled surface temperature and precipitation, derived from the Arctic MM5, are then used to drive the glacier PTAA mass balance model. Three 10-year time slice simulations (2010-2019, 2050-2059, and 2090-2099) are performed, representing increases of atmospheric CO2 from current to increases specified by the A2B scenario. Probable future changes in surface temperature and precipitation over Alaska and NW Canada, estimated from these three runs, will be analyzed. Our preliminary results will be presented.
DE: 0700 CRYOSPHERE (4540)
DE: 0720 Glaciers
DE: 1600 GLOBAL CHANGE
DE: 1637 Regional climate change
SC: Cryosphere [C]
MN: Fall Meeting 2005