甘肃省近46a年降水结构空间变化分析

Study on the Spatial Variation of Annual Precipitation Structure over Gansu Province During Recent 46 Years

通过对甘肃省1960～2005年62个气象站逐日降水量的分析,得出反映年内降水结构的2类指标:不同强度降水日数构成和降水相关极值的空间变化特征。结果表明,全省范围内降水各指标均没有同质的变化,说明降水变化的空间差别很大,从区域平均值角度难以得到有用信息;而降水结构分析从微观解构宏观状况,可以更好地说明降水的变化特征。对降水结构的空间变化进一步分析说明,一个区域的降水是否有显著的变化趋势,是各降水相关指标变化的综合作用结果,这种组合非常复杂,通常不具备广泛的代表性,各个指标非显著性变化的组合结果可以是降水量要素的显著变化。

Based on the analysis of daily precipitation of 62 weather stations in Gansu Province from 1960 to 2005, it educed the characteristies of spatial variation of different intensity precipitation days and precipitation relative extremes, and those can reflect the structure of precipitaiton. The results show that there isn＇ t any homogeneous variation over the whole province for each indicator, and the spatial distinction of precipitation variation is great. Thus, the regional average of precipitation is meaningless and the structure is more powerful to explain the change of precipitation, for which decomposed the dim unitary situation into vivid particular phenomena. The farther research on spatial variation of precipitation structure indicates that a significant variation of precipitation in a specific region is a synthetical consequence of the interactions among all indicators. This synthesis procedure is very complicated, and usually has not broad representation. Even nonsignificant variation of each indicator can bring forth a significant variation of precipitation.