1960—2014年茂名电白日照的变化特征

Characteristics of Sunshine Duration Variation of Dianbai,Maoming From 1960 to 2014

根据茂名市电白区国家基准气候站1960—2014年共计55年的日照时数资料,采用线性倾向估计和数理统计、小波分析、M-K检验等方法,分析电白日照时数的变化趋势。结果表明：近55年来电白日照时数呈减少趋势,年变化率为-6.05 h/年;月变化中,最少月份出现在3月,最多在7月;季节变化基本和年变化趋势一致,都呈减少趋势,但减少的幅度不尽相同,春季最多、夏季最少;年日照时数主要存在2个不同尺度的周期变化,分别是18年左右的长周期和2~4年的短周期;年日照时数的突变点在1984年。电白年日照时数与风速呈正相关,与总云量、低云量、降水量、相对湿度、水汽压呈负相关。

Using 55 years（ from 1960 to 2014） of sunshine duration（ SD） data from a national base climate observation station in the city of Maoming and the methods of linear tendency estimate,mathematical statistics,wavelet analysis and Mann-Kendall test,we studied the variation trend of the SD in Dianbai. The result is shown as follows. For the 55 years,the SD has been decreasing at a rate of- 6. 05 h / year. For the monthly variation,April has the least SD and July the most. Seasonal variations are consistent with annual variations,both decreasing in trends but with different magnitude; largest reduction occurs in spring but least reduction in summer. Two main periodic variations of different scales are found in the annual SD,one being a long period,about 18 years,and the other a short one,from 2 to 4 years. A point of abrupt SD change occurred in 1984. The SD of Dianbai varies in positive correlation with the wind speed while changing in negative correlation with total cloudage,low-level cloudage,rainfall amount,relative humidity and water vapor pressure.