Intercomparison of global precipitation products: The third Precipitation Intercomparison Project (PIP-3)

A see of global, monthly rainfall products has been intercompared to unders tand the quality and utility of the estimates. The products include 25 obse rvational (satellite based), four model, and two climatological products. T he results of the intercomparison indicate a very large range (factor of 2 or 3) of values when all products are considered. The range of values is re duced considerably when the set of observational products is limited to tho se considered quasi-standard. The model products do significantly poorer in the Tropics, but are competitive with satellite-based fields in midlatitud es over land. Over ocean, products are compared to frequency of precipitati on from ship observations. The evaluation of the observational products poi nts to merged data products (including rain gauge information) as providing the overall best results.