1971—2018年金华地区冬季降水特征研究

Characteristics of winter precipitation in Jinhua area from 1971 to 2018

为了探究金华地区冬季降水特征和极端降水情况,利用1971—2018年金华地区的实测地面降水资料,运用线性倾向估计、滑动平均、百分位阈值和小波分析等方法,对金华地区48年冬季降水变化进行了研究分析.结果表明:1)48年间,金华地区冬季降水量总体呈上升趋势,降水天数呈下降趋势,说明单次降水的强度增大,极端降水在2000年后出现的频次增加;2)冬季不同月份的降水特征不同,2月份降水量最多,降水天数最多,降水强度最大,12月份干湿变化大,容易出现气象和农业灾害;3)冬季降水量存在4 a,12 a和28 a左右的周期震荡,变化最明显,冬季降水天数周期震荡总体不明显,但单个月份的周期震荡较强烈,1月份的降水天数存在较明显的24 a震荡周期.研究成果可为金华地区的冬季降水机制研究和防灾减灾工作提供一定的参考.

In order to explore the winter precipitation characteristics and extreme precipitation situation in Jinhua area,by using the measured surface precipitation data in Jinhua area from 1971 to 2018 and the methods of linear tendency estimation,moving average,percentile threshold and wavelet analysis,the change of winter precipitation in Jinhua area in 48 years was studied and analyzed.The results showed that:in 48 years,the winter precipitation in Jinhua area increased generally,and the number of precipitation days decreased,which indicated that the intensity of single precipitation increased.The frequency of extreme precipitation increased after the year 2000;the precipitation characteristics of different months in winter were different,the precipitation in February was the most,the number of precipitation days was the most,the precipitation intensity was the largest,and the dry and wet changes in December were significant,which made more prone to meteorological and agricultural disasters;the precipitation in winter had periodic oscillations of about 4,12 and 28 years,with the most obvious changes,and the periodic oscillations of winter precipitation days were not obvious as a whole.However,the period oscillation of a single month was strong,and the precipitation days in January had obvious 24-year oscillation period.The research results could provide some reference for winter precipitation mechanism research and disaster prevention and mitigation work in Jinhua area.