近46年西南地区晴天日照时数变化特征及其原因初探

The Regional and Spatiotemporal Characteristics of Sunny Sunshine Duration in Southwest China during Recently 46 years and Its Formation Reason

利用1960-2005年西南地区93个气象站晴天日照时数资料,对西南地区晴天日照时数的时空分布特征进行分析。结果表明:(1)西南地区晴天日照时数呈现盆地地区低、中部山区高的分布,夏季高于冬季,冬季盆地最低值可降到5h·d-1以下。(2)近46年晴天日照时数呈现阶段性的下降趋势,其中年平均、夏季和冬季的趋势系数分别为-0.82,-0.86和-0.79,均通过了0.001的显著性水平检验。(3)西南地区大、中、小城市晴天日照时数的变化特征与整个地区的平均结果基本一致,而且大城市晴天日照时数下降幅度比中小城市要大,年平均日照时数的回归系数分别为-0.25,-0.19和-0.08h·d-1·(10a)-1。(4)西南地区大城市散射辐射与晴天日照时数有较好的对应关系,年平均、夏季和冬季的相关系数分别为-0.726,-0.818和-0.555,均通过了0.001的显著性水平检验。(5)西南地区年平均气溶胶指数呈现盆地地区高、四周低的分布特征,这与晴天日照时数的分布基本一致,而且气溶胶指数在过去27年来主要呈现一个逐年上升的变化趋势,与同期晴天日照时数基本一致。(6)晴天日照时数与同期西南地区GDP存在一定的相关性。

Using the data set of sunshine duration at 93 stations in Southwest China during recently 46 years, the regional and spatiotemporal characteristics and its formation reason were analysed. The results show that： （1） The sunny sunshine duration in Sichuan Basin is lower than other places; and the highest value is in central mountainous area. The sunny sunshine duration in summer is higher than in winter, and the lowest value in winter in Sichuan Basin can be down to below 5 h·d-1. （2） The variation of sunny sunshine duration in recent 46 years revealed an obvious decline trend, and the trend coefficients in annual average, summer and winter are -0.82, -0.86 and -0.79, respectively, passed the significant level at 0／^001. （3） The variation of sunny sunshine duration in different cities is consistent with the regional averaged, and the decline extent of sunny sunshine duration in big cities is larger than that in medium and small cities; the annual mean regressive coefficients are -0.25, -0.19 and -0.08 h·d-1·（10a）-1. （4） The variation of sunny scattered radiation is similar to sunny sunshine duration at big cities in Southwest China, and the correlative coefficients of annual average, summer and winter are -0.726, -0.818 and -0.555, passed the significant level at 0.001. （5） Similar to sunny sunshine duration, the distribution of aerosol index over Southwest China also shows that the value in Sichuan Basin is higher than that in other places, and there is an increasing variation trend, which leads to the increased sunny sunshine duration. （6）There is a good simultaneous correlation between the variation trend of sunny sunshine duration and GDP in Southwest China.