西昌近60年日照时数的变化特征分析

Analysis on Variation Characteristics of Sunshine Hours in Xichang in Recent 60 Years

为研究西昌近60年日照时数变化特征,利用中国气象数据网1960-2019年西昌逐月日照时数气象资料,采用线性趋势倾向分析、Mann-Kendall突变检验法、Morlet小波分析,分析西昌日照时数的变化特征。结果表明:(1)日照时数整体呈显著的下降趋势,减少速率为-54.7 h/10a,远低于中国西南地区平均减少速率。(2)日照时数四季均呈下降趋势,春季日照时数最多,秋季日照时数最少。夏季减少速率最大,冬季减少速率最小。(3)各月日照时数年际变化均呈减少的趋势。(4)日照时数在1989年开始发生突变,通过小波分析确定周期为28 a。

In order to study the variation characteristics of sunshine hours in Xichang in recent 60 years,the monthly sunshine hours meteorological data of Xichang from 1960 to 2019 were used in this paper.The variation characteristics of sunshine hours in Xichang were analyzed by linear trend analysis,Mann Kendall mutation test and Morlet wavelet analysis.The results show that:(1) The number of sunshine hours as a whole showed a significant downward trend,with a reduction rate of-54.7 h/10 a,which was much lower than the average decrease rate in Southwest China.(2) The sunshine hours showed a decreasing trend in four seasons,with the most sunshine hours in spring and the least in autumn.The decreasing rate is the highest in summer and the lowest in winter.(3) The interannual variation of sunshine hours in each month showed a decreasing trend.(4) The sunshine hours began to change in 1989,and the period was determined to be 28 years by wavelet analysis.