87th AMS Annual Meeting

Wednesday, 17 January 2007: 5:00 PM
Detecting Trends in Tropical Rainfall Characteristics, 1979-2003
214D (Henry B. Gonzalez Convention Center)
William K. M. Lau, NASA/GSFC, Greenbelt, MD
We find a significant shift in the probability distribution functions of tropical rainfall during the period from 1979-2003, from analyses of two state-of-the-art blended space-based and ground-based global rainfall data Global Precipitation Climatology Project (GPCP) and Climate Prediction Center Merged Analysis Product (CMAP). This shift features a positive trend in occurrence of extreme heavy (top 10% by rain amount), and in light (bottom 5%) rain events, and a negative trend in moderate (25-75%) rain events in the tropics during 1979-2003. The trends are consistent in both datasets and are in overall agreement with the Climate Research Unit (CRU) gauge-only rainfall data over land. The possible relationship of the trends with respect to long-term shift in rainfall characteristics i.e., warm, cold, and mixed-phased rain, is discussed.

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