近55年来中国不同强度降雨的时序变化特征研究

采用1961—2015年535个气象站点数据,根据中国气象局颁布的降雨强度等级划分标准,将降雨事件分为小雨、中雨、大雨、暴雨、大暴雨、特大暴雨6种强度,后三者记为总暴雨,六者合计为总降雨,从年际雨量和雨日两方面出发,将中国整体看做一个对象,首先计算1961—2015年535个站点不同强度降雨逐年雨量和雨日总和;然后计算不同强度降雨雨量和雨日总和的变化趋势;最后诊断不同强度降雨雨量和雨日对总降雨雨量和雨日贡献的变化趋势。结果表明,1961—2015年中国小雨呈减少趋势,大雨和总暴雨呈增加趋势,总降雨呈现先增加、后减少的"曲棍球"现象。除北方地区外,中国多数地区降雨以增加趋势为主,并朝着极端化方向发展。在降雨贡献率方面,小雨对总降雨的贡献呈减少趋势,而其他强度降雨对总降雨的贡献均呈增加趋势。暴雨对总暴雨的贡献在减少,而大暴雨和特大暴雨对总暴雨的贡献均呈增加趋势,说明中国暴雨强度在增加。虽然中国不同地区不同强度降雨对总降雨的贡献率不同,但多数地区强降雨对总降雨的贡献率呈增加趋势。通过对比6种不同强度降雨的雨量和雨日,可以发现中国强降雨事件在增加,降雨强度在朝着极端化方向发展。

Temporal Variation Characteristics of Different Intensities of Rainfall over the Past 55 Years in China

Using the data of 535 meteorological stations from 1961 to 2015,according to the precipitation intensity grading standard issued by the China Meteorological Administration,rainfall events can be divided into light rainfall,moderate rainfall,heavy rainfall,storm rainfall,torrential rainfall and severe storm rainfall,in which the latter three grades constitute total stromrainfall,while all six grades constitute total rainfall.Westarting from the annual rainfall amounts and rainfall days,taking 535 stations as a whole.Firstly,we calculate the sum of 535 stations' rainfall amounts and rainfall days with different intensities year by year from 1961 to 2015.Secondly,we calculate the trend of rainfall amounts and rainfall days with different intensities.Finally,diagnosis the contributions of rainfall amounts and rainfall days with different intensities to total rainfall amounts and rainfall days.The results showed that light rainfall showed a trend of decrease in China from 1961 to 2015,heavy rainfall and the total storm rainfall showed increasing trend,total rainfall showed first increase then decrease trend,which was alike the "hockey" phenomenon.In addition to the northern region,rainfall in most regions of China presented increasing trend and was towards to the direction of extremes.In terms of rainfall contributions,light rainfall's contribution to total rainfall showed a trend of decrease,but the other intensity rainfalls' contribution to total rainfall all showed a trend of increase.Storm rainfall's contribution to total storm rainfall was in decline,while torrential rainfall's and severe storm rainfall's contributions to total rainstorm all showed a trend of increase.All these indicate that storm rainfall intensity was increasing in China.Although the contribution rate of different intensity rainfall to the total rainfall was different in different regions of China,the contribution rate of heavy rainfall to the total rainfall in most regions was increasing.Through comparing the rainfall amounts and rainfall days of six different intensities,it could be found that the heavy rainfall events are increasing,the rainfall intensity in China was changing to the direction of extremes.