HR: 1340h
AN: C23A-1137    [Abstracts]
TI: A Greenland ice sheet surface mass balance uncertainty model
AU: * Box, J E
EM: box.11@osu.edu
AF: Byrd Polar Research Center, 1090 Carmack Rd, Scott Hall rm 108 The Ohio State University, Columbus, OH 43210-1002 United States
AB: The Polar MM5 atmospheric model run in data assimilation mode has provided Greenland ice sheet surface mass balance estimates for specific time periods, i.e. balance-years, including the capability for multi-year change assessments. Comparison of modeled surface mass balance with independent in-situ observations from Greenland ice sheet sites reveals model biases that are partially systematic. It is possible to remove the systematic component of the bias with statistical regression given some independent variable that demonstrates some spatial co-variance, e.g. with elevation. Furthermore, residual post-calibration errors suggest uncertainties that have additional systematic spatial variations. It was therefore possible to map uncertainty and integrate the uncertainty in mass units for whole ice sheet mass change uncertainty estimates. Surface mass balance uncertainty quantified as such suggests the envelope of uncertainty larger than which a change must be to be considered certain or significant. This presentation focuses on this uncertainty model and what developments in model physical parameterizations, spatial and temporal resolution, and boundary conditions are needed to refine uncertainties to satisfy conservative uncertainty thresholds, i.e. 5-10% margins of error.
DE: 0726 Ice sheets
DE: 0798 Modeling
DE: 1218 Mass balance (0762, 1223, 1631, 1836, 1843, 3010, 3322, 4532)
DE: 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions (0762, 1218, 3319, 4550)
DE: 4540 Ice mechanics and air/sea/ice exchange processes (0700, 0750, 0752, 0754)
SC: Cryosphere [C]
MN: Fall Meeting 2005