黑龙江省夏季雨日变化及前期环流特征

Variation of summer rain days and characteristics of early circulation in Heilongjiang

利用1961-2017年黑龙江省62个台站的雨日资料,采用小波分析、相关系数与趋势系数等方法分析,研究夏季不同级别雨日的气候变化趋势.结果表明,黑龙江省夏季各级雨日变化趋势暴雨、大雨以上日数呈现略增加趋势,而中雨和小雨以上日数呈现略减少的趋势;夏季降水日数平均分布,各级别以上的日数分布中心基本是一致的。用黑龙江省夏季大雨以上日数做代表进行分析,小波分析表明存在20a(年)左右的年代际变化周期,还有9a左右、6a左右和3a左右的年际变化周期;前期北半球500hPa(百帕)环流场特征,初冬季由极地到太平洋距平场“-+-”形式,夏季大雨以上日数易偏多,反之,排列为“+-+”形式,夏季大雨日数易偏少。

Based on the data of 62 stations in Heilongjiang Province from 1961 to 2017, the climate change trend of different grades of rainy days in summer was studied by means of wavelet analysis, correlation coefficient and trend coefficient. The results showed the change trend of all kinds of rainy days in Heilongjiang Province in summer.Rainstorm Day and heavy rain day showed a slightly increasing trend, while the days above moderate rain and light rain showed a slightly decreasing trend. The distribution of summer precipitation days is basically the same, and the distribution centers of days above all levels are basically the same. The number of days with heavy rain in summer in Heilongjiang Province is used as representative for analysis. The wavelet analysis shows that there exists an interdecadal variation period of about 20 years and an interannual variation period of about 9 years, 6 years and 3 years. The characteristics of the 500 hPa circulation field in the northern hemisphere in the early winter are from the polar to the Pacific anomaly field in the form of -+-, the number of days with heavy rain in summer is more, on the contrary, it is arranged in the form of -+-, and the number of days with heavy rain in summer is less.