摘要:利用1961～2017年我国东北地区96个站点逐日降水、相对湿度和气温等资料，运用趋势分析、Mann-Kendall突变检验等方法，分析了东北地区夏季小雨、中雨、大雨、暴雨的气候变化特征，并对东北地区小雨量减少进行了成因分析，得出主要结论如下：东北地区夏季总降水量与各量级降水频率和贡献率均呈显著的正相关，总降水量的多寡受大雨频率及贡献率的影响最为显著。小雨量和中雨量的减少是导致东北地区夏季总降水量减少的主要原因，暴雨量受暴雨贡献率增加影响呈增加趋势。小雨量和小雨贡献率在1993年前后出现了年代际突变，小雨贡献率的突变是造成小雨量年代际突变的内在因素。东北地区总降水量呈减少趋势的站点有72个；小雨量呈减少趋势的站点有85个，显著减少的站点数达到25个；中雨量呈减少趋势的站点有70个，显著减少的站点只有9个；大雨量呈增加与减少趋势的站点数相当；而暴雨量呈增加趋势的站点数大于减少的站点数。从云形成机制角度出发，分别讨论大气水汽、温度、气溶胶浓度变化对东北地区小雨量减少的影响。结果表明，在全球变暖背景下东北地区气温增加和气溶胶浓度增加是导致该地区小雨量减少的主要原因。
关键词:小雨/
气溶胶/
降水频率/
降水贡献率/
突变/
气候变暖
Abstract:Based on the daily precipitation, relative humidity, and air temperature data during 1961?2017 from 96 stations in Northeast (NE) China, through trend analysis and the Mann-Kendall test method, the climate change characteristics of light rainfall, moderate rainfall, heavy rainfall, and torrential rainfall in summer and the causes of the decreasing trend of light rainfall frequency over NE China are analyzed. The main results are as follows: A significant positive correlation exists between the total precipitation over NE China and all types of precipitation frequency and contribution, and the total precipitation is mainly influenced by the frequency and contribution of heavy rain. The decrease in light rainfall and moderate rainfall is the main cause of the decrease in total precipitation in summer over NE China, and the torrential rainfall influenced by the increase in the torrential rainfall contribution shows a rising tendency. Furthermore, an interdecadal abrupt change in light rainfall and light rainfall contribution occurred around 1993, and the interdecadal abrupt change in light rainfall contribution has resulted in the interdecadal abrupt change in light rainfall. A certain decreasing trend of the total precipitation at 72 stations over NE China 85 stations showed a certain decreasing trend of the light rainfall, among which 25 stations show a significant decreasing trend; moreover, 70 stations show a certain decreasing trend of moderate rainfall, among which only nine stations show a significant decreasing trend; the number of stations that show an increasing trend of heavy rainfall is comparable to the number of those that show a decreasing trend, and the number of stations that show an increasing trend of the torrential rainfall is greater than the number of those that show a decreasing trend. Regarding cloud formation, the effects of the changes in water vapor, temperature, and aerosol concentration on the reduction in light rainfall in NE China are analyzed. The results show that the global temperatures rising and increased aerosol concentration are the main causes of the decreasing light rainfall in NE China.
Key words:Light rainfall/
Aerosol/
Precipitation frequency/
Precipitation contribution/
Abrupt change/
Global warming
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