1978-2019年鄱阳湖流域小时强降水气候变化特征

Climatic Characteristics of Hourly Heavy Precipitation over the Poyang Lake Basin from 1978 to 2019

利用鄱阳湖流域79个国家气象站逐时降水资料,采用Sen斜率估计、Mann-Kendall检验、小波分析等统计诊断方法,分析了1978-2019年鄱阳湖流域小时强降水的时空变化特征。结果表明:1)鄱阳湖流域小时强降水量及其对总降水贡献率呈现显著的增加趋势,小时强降水时数增加显著而强度则几乎无变化。2)鄱阳湖流域小时强降水量主要呈现准4-5 a短周期变化。3)鄱阳湖流域小时强降水在6月出现次数最多,8月的小时强降水贡献率最大;4-9月小时强降水量和降水时数均呈增加趋势,但3月两者均呈现减少趋势。4)鄱阳湖流域小时强降水日变化分布呈现双峰结构,16-20时是主峰时段,06-09时为次峰时段。5)鄱阳湖流域小时强降水量分布主要呈现“东多西少”特征,且部分强降水量中心呈现增长趋势,需引起足够重视。

Based on the hourly precipitation data of 79 meteorological stations over the Poyang Lake Basin during1978-2019,the spatial and temporal variation characteristics of hourly heavy precipitation over the Poyang Lake Basin were investigated using Sen slope estimation,Mann-Kendall test and wavelet analysis.The results showed that:1)The hourly heavy precipitation and its contribution rate to the total precipitation over the Poyang Lake Basin presented a significant increasing trend,and the frequency of hourly heavy precipitation increased significantly,while the strength of which exhibited stable.2)The hourly heavy precipitation over the Poyang Lake Basin mainly presented a cycle variation of about 4-5 years.3)In June,the hourly heavy rainfall over the Poyang Lake was the most,and the contribution rate of hourly heavy rainfall in August was the highest.The frequency and precipitation of hourly heavy rainfall during April to September both presented positive trends,while in March which showed decreasing trends.4)The diurnal variation of hourly heavy rainfall presented a bimodal structure.The main occurrence period of hourly heavy rainfall was from 16:00 BT to 20:00 BT,and the secondary peak period was from 06:00 BT to 09:00 BT.5)The distribution of hourly heavy precipitation over the Poyang Lake Basin were more in the East and less in the west.The center of hourly heavy precipitation partly presented increasing trends,which need to be paid more attention.