甘肃省近54年日照时数变化特征及影响因素

笔者运用甘肃省1960—2013年28个气象站逐月日照时数资料,采用气候趋势分析法对月、季和年日照时数的变化特征进行分析,同时研究降水量、风速、水汽压和相对湿度对日照时数变化的影响。结果表明:近54年来,年日照时数呈不明显的增加趋势,增加速率为1.2 h/10 a。甘肃最高和最低日照时数出现在5月和2月。四季日照时数春季和秋季呈增加趋势,春季增加较明显,冬季和夏季呈减少趋势。甘肃年日照时数与年均降水、水汽压和相对湿度均呈负相关关系,相关系数分别为-0.34、-0.27和-0.51,与风速呈正相关。

Sunshine Duration Variation and Its Influencing Factors in Recent 54 Years in Gansu Province

The variation of annual, seasonal and monthly sunshine duration were analyzed by using climate trends method, based on monthly sunshine duration of 28 meteorological stations in Gansu Province from 1960 to 2013, and the effect of precipitation, wind speed, vapour pressure and relative humidity change on sunshine duration were studied. The results showed that: Gansu annual sunshine duration in recent 54 years had an increasing trend, and the rate was 1.2 h/10 a. The maximum and minimum sunshine duration presented in May and February respectively. In spring and autumn the sunshine duration showed an upward trend, the spring increase was obvious, while there was a decreasing trend in summer and winter. The sunshine duration had a negative correlativity with annual precipitation, vapour pressure and relative humidity, correlation index were -0.34, -0.27 and -0.51, respectively, while it had a positive correlativity with wind speed.