Construction and Analysis of a Precipitation Recycling Model

In this paper a precipitation recy cling model is constructed over the main Yangtze River basin area (100°E～120°E, 25°N～35°N).Accordingly, precipitation recycling ratio and its seasonal variations are calculated on grid scale.It is estimated that annual mean 10% of all the rain that falls in the whole studying region is contributed by evaporation within the same region.The results also indicate that the fraction of precipitation that is locally drived varies substantially with location and season.For the region under study, the contribution of regional evaporation to regional precipitation lies between 0.03 to 0.19, but reaches as high as 0.41 or 0.46 in late summer in two special locations-the northwestern part of Sichuan Basin and the northern part of Huanan area.The degree to which regional precipitation is supplied by recycled moisture is a potentially significant climate feedback mechanism in the land-atmpspheric interaction.