HR: 0800h
AN: C51B-0393    [Abstracts]
TI: Large Contribution of Antarctic 'Small' Glaciers to Sea-level Rise
AU: de Woul, M
EM: mattias.deWoul@natgeo.su.se
AF: Department of Physical Geography and Quaternary Geology, Stockholm University, Stockholm, 10961, Sweden
AU: Radic, V
EM: valentina.radic@gi.alaska.edu
AF: Geophysical Institute, University of Alaska, Fairbanks, 903 Koyukuk Dr, Fairbanks, AK 99775, United States
AU: * Hock, R
EM: regine.hock@gi.alaska.edu
AF: Geophysical Institute, University of Alaska, Fairbanks, 903 Koyukuk Dr, Fairbanks, AK 99775, United States
AU: Dyurgerov, M
EM: mark.dyurgerov@natgeo.su.se
AF: Department of Physical Geography and Quaternary Geology, Stockholm University, Stockholm, 10961, Sweden
AB: Glaciers have generally experienced mass loss in the last couple of decades with strongly accelerated ice wastage during the last decade. We present a methodology for grid-based global assessment of mass loss of "small" glaciers defined as all glaciers outside the ice sheets in Greenland and Antarctica, and their sea-level equivalent during the period 1961-2004. Regional and global estimates of glacier mass loss are computed from glacier area, mass balance sensitivities, and ERA-40 temperature and precipitation trends for each glacierized grid cell. Annual and seasonal mass balance sensitivities to temperature and precipitation changes are computed for almost 100 glaciers based on calibration of a simple temperature-index regression model to observations of seasonal mass balances using ERA-40 re-analysis data as climate input. The mass balance sensitivities are then extrapolated to each glacierized grid cell by means of a continentality index and precipitation as derived for each grid cell of the ERA-40 grid. Results indicate that previous global assessments based on extrapolation of measured mass balances may have underestimated glacier mass loss during the last 40 years due to underestimation of high mass balance sensitivities in areas were measurements are scarce. We obtain a global sea-level rise equivalent estimate of 0.62 mm/yr, of which one third originates from the glaciers and ice caps around Antarctica, and hence their contribution is considerably higher than previously assumed.
DE: 0760 Engineering
DE: 0762 Mass balance (1218, 1223)
DE: 0776 Glaciology (1621, 1827, 1863)
SC: Cryosphere [C]
MN: 2007 Fall Meeting