Greenland ice sheet: High-elevation balance and peripheral thinning

Aircraft Laser-altimeter surveys over northern Greenland in 1994 and 1999 h ave been coupled with previously reported data from southern Greenland to a nalyze the recent mass-balance of the Greenland Ice Sheet. Above 2000 meter s elevation, the ice sheet is in balance on average but has some regions of local thickening or thinning. Thinning predominates at Lower elevations, w ith rates exceeding 1 meter per year close to the coast. Interpolation of o ur results between flight lines indicates a net loss of about 51 cubic kilo meters of ice per year from the entire ice sheet, sufficient to raise sea L evel by 0.13 millimeter per year-approximately 7% of the observed rise.