一个降水再循环模型的建立及分析

陆-气相互作用是当今水文科学界和大气科学界共同瞩目的一个前沿课题。为寻求陆-气相互作用的某些信号,在长江流域的主体区域上建立了一个降水再循环模型,并分析了这一区域降水的不同水汽来源。依据再循环降水率这个反映陆面过程对当地气候影响的定量指标,得出了一些很有实际意义的结论。

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.