Glacier Mass Loss in Alaska from Airborne Lidar Altimetry

Changes in the flow dynamics of marine terminating glaciers remain the largest unresolved uncertainty in projections of sea level rise. While Alaska glaciers are losing about -50 Gt/yr, it remains unclear what the role marine dynamics have on the regional mass balance. The University of Alaska Fairbanks LiDAR Altimetry Program has flown repeat surveys of glaciers in Alaska from 1994 to 2014 and has made direct assessments of glacier mass balance on 46% of Alaska's glacier area and 81% of the tidewater glacier area. We reconstruct regional mass balance using collective estimates of individual glacier mass balance and combine these data with calving rate estimates to assess the relative roles of surface mass balance and iceberg calving on the mass balance of the Alaska region.