辽宁省大雨以上降水日数分布与趋势分析

大雨以上降水日数反映了降水的非平均状况,对于气候异常变化和预报预测都有非常重要的意义。以辽宁省作为研究区域,根据1957-2013年辽宁省内23个和省外4个雨量站点的逐日降水数据,利用趋势系数法计算大雨以上降水日数的变化趋势,通过Mann-Kendall检验法检测突变。采用Morlet小波技术分析年际与各季节的变化周期;借助ArcGIS软件工具的Kriging插值和IDW插值模块对研究区进行空间分析。结果表明：辽宁省大雨以上降水日数的空间变化表现为由东南向西北递减;年际以及春、夏两季的周期大约为38年,秋季周期约为15年;大雨以上降水日数的年际变化呈现微弱的减少趋势,不同季节略有差异。57年来,辽宁省大雨以上降水日数变化总体呈现下降趋势,辽中地区下降趋势略有滞后,辽西地区变化情况较其他区域相对复杂。

Distribution and trend analysis of heavy precipitation days in Liaoning Province

Precipitation has been a hot topic in the study of climate change and forecast. Heavy precipitation days reflect the condition of concentrated precipitation that has a great significance. Based on the daily precipitation data of 27 rainfall stations from 1957 to 2013 in Liaoning Province, trend coefficient method was used to calculate the trend of heavy precipitation days. Mutation was tested by the Mann-Kendall method. The cycle of heavy precipitation days was explored using the Morlet wavelet method. With the help of the ArcGIS software, this study analyzed the spatial distribution of heavy precipitation days. Both Kriging and inverse distance weighted (IDW) interpolation method were used in this study. The results show that heavy precipitation days decreased from the southeast to the northwest in Liaoning Province. Maximum days of precipitation were found in Dandong. Inter-annual variation of heavy precipitation showed a cycle of about 38 years. Overall the number of heavy precipitation days decreased, but not significantly. Only a few areas passed the significance test. In central Liaoning Province the change slightly lagged, and changes in western Liaoning Province were complex. Seasonally, a 38 year cycle was detected for the spring and the summer—the same as the annual cycle, and a 15 year cycle was found for the autumn. Inter-annual variation of heavy precipitation days showed a slight decreasing trend, and it slightly differed in different seasons.