In this study,the temporal and spatial variations of observed global oceanic precipitation during 1979-2010 are investigated.It is found that the global trend in precipitation during this period varies at a rate of 1.5％/K of surface warming while the rate is 6.6％/K during 2006-2010.The precipitation is highly correlated with Sea Surface Temperature （SST） in both the temporal and the spatial patterns since the strong 1997-98 E1 Ni（n）o event.Considering the distributions of precipitation and SST,seven oceanic regions are classified and presented using the observed Global Precipitation Climatology Project （GPCP） data and Extended Reconstructed Sea Surface Temperatures,version 3 （ERSST.v3） data.Further examining the mechanisms of the classified oceanic precipitation regions is conducted using the Tropical Rainfall Measuring Mission （TRMM） satellite,GFDL-ESM-2G model precipitation and SST data and Hadley Center sea ice and SST version 1 （HadISST1） data.More than 85％ of global oceanic precipitations are controlled by either one or both of the warmer-get-wetter mechanism and wet-get-wetter mechanism.It is estimated that a 0.5 SST signal-to-noise ratio,representing the trend of SST time series to the standard deviation,is a criterion to distinguish the mechanism of a region.When the SST ratio is larger than 0.5,the precipitation of this region is controlled by the warmer-get-wetter mechanism.SST,rather than the humidity,is the pivotal factor.On the other hand,when the SST ratio is less than 0.5,the precipitation is controlled by the wet-get-wetter mechanism.The SST variability is a significant factor contributing to the precipitation variation.
