1951—2018年衢州市椪柑采摘期连阴雨天气变化特征

基于1951—2018年衢州市椪柑采摘期降水量、雨日、日照时数、相对湿度等逐日气象资料，应用统计分析和小波分析方法，分析椪柑采摘期连阴雨天气变化特征及其大气环流背景。结果表明：1951—2018年衢州椪柑采摘期连阴雨日数、次数和强度呈略微增加趋势、滑动3 d无雨次数呈减少趋势；滑动3 d无雨次数存在明显的5 a、7 a和15 a左右的年际和年代际周期变化规律，并且均呈现缩短趋势；椪柑采摘期连阴雨较强年亚欧地区呈两高一低的径向型环流，强冷空气南下活动较频繁、东移缓慢，偏南暖湿气流活跃，致使冷暖空气在中国长江中下游地区长时间交汇，导致连阴雨天气。

Change characteristics of continuous rain during the picking period of ponkan in Quzhou from 1951 to 2018

Studying the continuous rain characteristics and atmospheric circulation background during the picking period of ponkan in Quzhou can provide a scientific guide for picking ponkan on time.Based on the daily weather data such as precipitation, rainy days, sunshine hours, relative humidity, etc., this study analyzed the change characteristics of the continuous rain and atmospheric circulation background during the picking period of ponkan from 1951 to 2018 using the statistical analysis and wavelet analysis methods.The results show that the number of consecutive rainy days, frequency, and intensity of rain during the picking period of Quzhou ponkans lightly increase, and the number of rainless days with a 3-day sliding decreases and shows the characteristics of 5 years and 7 years inter-annual and 15 years inter-decadal cyclical changes, and the cycles present a shortening trend.In the strong continuous rainy years during the ponkan picking period, a meridional circulation with two heights and one low prevails over the Asia-Europe region.Under such circumstances, strong cold air moves southward frequently and eastward slowly, and the southerly warm and humid airflow is active, which causes a convergence of warm and cold air in the middle and lower reaches of the Yangtze River for a long time.