中国近50年太阳直接辐射和散射辐射变化趋势特征

Variation trend of direct and diffuse radiation in China over recent 50 years

利用近50年(1961—2009年)14个站以及31年(1961—1991年)49个气象站点的地面直接辐射和散射辐射观测资料,采用线性倾向估计、小波分析和Mann-Kendall(M-K)统计检验等方法,分析了太阳直接辐射和散射辐射年际、季节的长期变化趋势特征、年代际距平、周期和突变点.研究表明:1)采用归一化的气候倾向系数方法,有更好的比较性,能较好地揭示辐射气候趋势的时空分布特征;2)全国太阳直接辐射和散射辐射总体呈下降趋势,但地区、年代际和季节有升降的差异;3)基于观测站点地理分布的特点,按气候带划分和站点占有的百分比进行分类统计分析,更能阐明辐射长期变化具有一定的地带性和局地差异性;4)采用小波分析和M-K统计检验方法分析,得到各地辐射周期和突变时段的异同;5)大部分省际大城市的直接辐射和散射辐射长期变化的下降趋势较其他城市更明显,这可能与城市化发展快慢引起的环境要素变化有关.

Using the direct and diffuse solar radiation data during 1961—2009 from 14 stations and during 1961—1991 from 49 stations in China,and the method of linear regression（taken time as an independent variable）,wavelet analysis and Mann-Kendall statistical test,we analyze the characteristics of the direct and diffusion radiation from different aspects including decadal variation,long-term seasonal change,inter-decadal anomaly,cycle and abrupt change.The results are as follows.1） The spatial and temporal distribution of the climatic trend for the direct and diffuse radiation are revealed by using the normalized climatic tendency coefficient.At the same time,these results are comparable.2） The direct solar and diffuse radiation in China show decreasing trend,but there are many differences in region,inter-annual and seasonal trend.3） Based on the characteristics of the geographical distribution on observation stations and according to the climate zone,the classification and the statistical analysis of the percentage of site occupation the long-term changes of the radiation can be clearly shown to have the characteristics of area and local difference.4） Using wavelet and Mann-Kendall test method,the statistical results show that the radiations in different regions have different periods and abrupt change.5）The long-term variations of the direct and diffuse radiation in most big cities turn to decrease more obviously than in other cities.Some.Other studies show that such a climatic phenomenon may be caused by environmental factor change of urbanization related to the difference in development speed between cities.