Comparative analysis of snowfall accumulation over Antarctica in light of Ice discharge and gravity observations from space

Abstract

The remote and cold Antarctic continent presents unique challenges to quantify precipitation rates from space andin situobservations. This has resulted in large uncertainties in current estimates. In this study, we quantify annual precipitation rates over seven Antarctic basins using a novel mass budget (MB) approach, by building on the recent Landsat based estimate of ice discharge and changes in total water storage from GRACE. The MB precipitation rates are compared with those from CloudSat, GPCP, the Arthern precipitation climatology, the GPM constellation sensors, a few popular reanalysis products, and a regional climate model for two periods: 2007-2010 and 2013-2015. The new estimates are bounded by CloudSat precipitation rates with and without adjustment for the unmeasured near surface precipitation. GPM products significantly underestimate Antarctic precipitation rate, but capture spatial variability that is valuable for bias-adjustment. We find variable performance between products at basin scale, suggesting that an in-depth regional study of precipitation rates is necessary.