Signals of extreme weather conditions in Central Europe in GRACE 4-D hydrological mass variations

Abstract

We report evidence of observed extreme weather fluctuations in Central Europe by satellite gravimetry during the last five years. Heat waves, droughts, excessive rain, snowfall, and floodings occurred frequently during the study period. Such phenomena are primarily associated with hydrological mass variations that are manifested in the changes of the Earth's gravity field, sensitive to the Ka-band satellite-to-satellite ranging (KBR) measurements onboard of the gravity field mission GRACE twin-satellites 2002–2007. In our contribution we perform a regional analysis of GRACE data over Europe based on spherical wavelet/B-spline and global spherical harmonic solutions. Resulting temporal gravity field variations are expressed in terms of equivalent water mass variations which are subsequently compared and in balance with the net effect of precipitation and evaporation from the atmospheric flux convergence reduced by runoff from river gauge data for seven Central European river basins.