Northern Hemisphere Glacier and Ice Cap Surface Mass Balance and Contribution to Sea Level Rise

Abstract

ass changes and mass contribution to sea level rise from glaciers and ice caps (GIC) are key components of the earth?s changing sea level. GIC surface mass balance (SMB) magnitudes and individual and regional mean conditions and trends (1979?2009) were simulated for all GIC having areas greater or equal to 0.5 km2 in the Northern Hemisphere north of 25°N latitude (excluding the Greenland Ice Sheet). Recent datasets, including the Randolph Glacier Inventory (RGI; v. 2.0), the NOAA Global Land One-km Base Elevation Project (GLOBE), and the NASA Modern-Era Retrospective Analysis for Research and Applications (MERRA) products, together with recent SnowModel developments, allowed relatively high-resolution (1-km horizontal grid; 3-h time step) simulations of GIC surface air temperature, precipitation, sublimation, evaporation, surface runoff, and SMB. Simulated SMB outputs were calibrated against 1422 direct glaciological annual SMB observations of 78 GIC. The overall GIC mean annual and mean summer air temperature, runoff, and SMB loss increased during the simulation period. The cumulative GIC SMB was negative for all regions. The SMB contribution to sea level rise was largest from Alaska and smallest from the Caucasus. On average, the contribution to sea level rise was 0.51 ± 0.16 mm sea level equivalent (SLE) yr?1 for 1979?2009 and ~40% higher 0.71 ± 0.15 mm SLE yr?1 for the last decade, 1999?2009.