Satellite derived precipitation and freshwater flux variability and its dependence on the North Atlantic Oscillation

Abstract

The variability of satellite retrieved precipitation and freshwater flux from the ‘Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data’ (HOAPS) is assessed with special emphasis on the ‘North Atlantic Oscillation’ (NAO). To cover also land areas, a novel combination of the satellite derived precipitation climatology with the rain gauge based ‘Full Data Reanalysis Product Version 4’, of the ‘Global Precipitation Climatology Centre’ (GPCC) is used. This yields unique high-resolution, quasi-global precipitation fields compiled from two independent data sources. Over the ocean, the response of the freshwater balance and the related parameters to the NAO is investigated for the first time by using a purely satellite based data set.

A strong dependence of precipitation patterns to the state of the NAO is found. On synoptic scale this is in accordance with earlier findings by other satellite based and reanalysis products. Furthermore, the consistency of the combined HOAPS-3/GPCC data set allows also detailed regional analyses of precipitation patterns. The response of HOAPS-3 freshwater flux to the NAO is dominated by precipitation at mid and high latitudes, while for the subtropical regions the feedback of the evaporation is stronger.