近50年西宁市日照时数变化规律分析

Variation Characteristic of Sunshine Duration in Xining in Recent 50 Years

利用近50年西宁市日照时数实测资料,分析了其日照时数年代际、年际、季和月的变化特征,并用气候突变理论对其进行检验。结果表明,近50年西宁市日照时数呈减少趋势,其气候变化率为每10年减少75.1h;日照时数的年际变化幅度较大,峰值(1963年)与谷值(2007年)相差635.3h。日照时数存在明显的季节差异,各季日照时数年际变化从大到小依次为夏季>冬季>秋季>春季。各月日照时数呈减少趋势,其中减少趋势最显著的是1月,4月的最不明显。年日照时数在1983年发生了由多到少的明显突变。

The climate change characteristics of decade,annual,seasonal and monthly sunshine durations in Xining city were analyzed based on the observed data of sunshine duration in Xining city in recent 50 years.The resu1ts indicate that in recent 50 years,the sunshine duration decreased with a tendency of 75.1 h per ten years;the interannual variation amplitude is obvious;and the difference of the sunshine duration between 1963 and 2007 reaches up 635.3 h.There is obvious seasonal difference in sunshine duration,the decreasing amplitudes in summer and winter are more obvious than that of spring and autumn.The decreasing tendency is the most significant in January and less in April.The annual sunshine duration in 1983 occurred abrupt change from long to short.