Water balance of the Arctic drainage system using GRACE gravimetry products

Land water and snow mass anomalies versus time were computed from the inversion of 50 GRACE geoids (August 2002 to February 2007) from the RL04 GFZ release and used to characterize the hydrology of the Arctic drainage system. GRACE-based time series have been compared to snow water equivalent and snow depth climatologies, and snowfall for validation purpose. Time series of regional averages of water volume were estimated for the 11 largest Peri-Arctic basins. Strong correlations were found between the snow estimates and river discharges in the Arctic basins (0.49 to 0.8). Then changes in land water storage were compared to precipitation minus evapotranspiration fluxes to determine which flux of the hydrological budget controls the Arctic hydrology. Results are very contrasted according to the basin. Trends of snow and land water masses were 20 also computed over the 2003-2006 period. Eurasian basins lose snow mass whereas North American basins are gaining mass.