Assessment of various global freshwater flux products for the global ice-free oceans

For the global average field, evaporation and precipitation products of reanalysis are larger than satellite products in the tropical and subtropical regions. The large evaporation data values obtained by reanalysis are attributed to the low air specific humidity values and the differences between the bulk algorithms for the tropical and subtropical regions. Moreover, for the global water budget and the inter-annual variability and trends, the reanalysis precipitation product is largely dependent on its evaporation product. If we use reanalysis precipitation and satellite evaporation data, we obtain a negative value for the global ocean water budget. This study demonstrates the difficulty of using different evaporation and precipitation products to analyze the global hydrologic cycle.