HR: 1340h
AN: C23A-1143    [Abstracts]
TI: Screen temperature lapse rates over alpine and Arctic icefields: Implications for mass balance modeling
AU: * Marshall, S J
EM: shawn.marshall@ucalgary.ca
AF: University of Calgary, 2500 University Dr NW, Calgary, AB T2N1N4 Canada
AB: Networks of temperature dataloggers have been deployed since summer 2000 to monitor near-surface temperature lapse rates in two glaciated regions: the Haig Glacier, Canadian Rockies, and the Prince of Wales Icefield, Ellesmere Island, Canada. These networks span 1250 m and 1880 m of elevation, with instruments positioned at elevational intervals of ca.~100-m. Daily and monthly average temperatures from the spatial array provide a record of near-surface temperature lapse rates and mesoscale temperature variability over the two glaciated regions. Surface temperature lapse rates in the regions are systematically less than the free-air lapse rates that are typically adopted for extrapolations of sea-level temperature to higher altitudes. This has significant implications for downscaling or extrapolation of boundary-layer temperatures in regions with significant topographic relief, with associated impacts on glacier mass balance modeling. I illustrate this in analyses of observed vs.~modeled snowmelt in the two glaciated regions and discuss the uncertainties associated with lapse rate assumptions in glacier and icefield modeling.
DE: 0720 Glaciers
DE: 0726 Ice sheets
DE: 0762 Mass balance (1218, 1223)
DE: 1621 Cryospheric change (0776)
SC: Cryosphere [C]
MN: Fall Meeting 2005