甘肃不同强度降水日数变化对干旱灾害的影响

Impact of the variation of different intensity precipitation days on arid disaster in Gansu Province

采用甘肃省60个地面气象站1961～2004年3～10月日降水量,统计了历年3～10月的降水量,小雨、中雨、大雨、暴雨日数和连阴雨次数;用相关分析方法研究了干旱气象灾害对不同强度降水日数变化的响应。结果表明,降雨量即小雨、中雨、大雨、暴雨日数和连阴雨次数都呈减少趋势;干旱面积和粮食减产量呈增加趋势;降水量、连阴雨次数、中雨日数与干旱面积和粮食减产量之间呈显著负相关,小雨和大雨次之;连阴雨次数和中雨日数减少,是造成干旱面积扩大、粮食大幅度减产的重要因素。

Based on the precipitation data of 60 meteorological stations between March -- October in Gansu Province from 1961 to 2004, rainfall and days of light rain, moderate rain, heavy rain, torrent rain and times of successive rain days in March -- October were calculated, and response of arid meteorological disaster to variation of different intensity precipitation days were analyzed. The results are as follows： there has been a decrease in rainfall, days of light rain, moderate rain, heavy rain and torrent rain, and times of successive rain, while the drought area and the grain reduction have increased; rainfall and moderate rain days and times of successive rain have a much closer negative correlation with drought area and grain reduction than light rain and heavy rain do. Decreases of successive rain times and moderate rain days are important factors that enlarged the drought area and resulted in a considerable decrease in grain production.