怒江流域近30年太阳总辐射变化趋势

利用怒江流域河谷盆地的9个气象站1981～2008年的日照时数、云量、相对湿度等资料,分析了该流域太阳总辐射的时空分布、变化趋势等气候特征及其影响因子。结果表明,怒江流域年太阳总辐射1981～1997年呈明显下降趋势,为-161.1MJ/（m^2.10a）,1997年之后以111.3MJ/（m^2.10a）的速度上升。年总云量呈显著的减少趋势,减幅为0.18成/10a;而年低云量表现出与总云量相反的变化趋势,以0.32成/10a的速度增加。相对湿度的变化趋势与年太阳辐射的趋势相反,1981～1997年以3.1%/10a的速率增加,1997～2008年为明显的减少趋势,减幅为5.6%/10a。水汽压的变化和相对湿度的变化一致。低云量是怒江流域太阳总辐射变化的主要影响因子,它与太阳总辐射存在明显的负相关关系。

Variation Trend of the Total Solar Radiation in Nujiang Basin in Recent 30 Years

Based on 9 observational stations data of sunshine duration,cloud cover and relative humidity over basin valley of Nujiang Watershed from 1981 to 2008,the spatial and temporal distribution and change trend of total solar radiation in this basin were analyzed as well as its impact climatic factors. The results showed that annual solar radiation has decreased obviously in Nujiang basin from 1981 to 1997,and its decrease was 161.1 MJ/(m2·10a). But it was increasing at the rate of 111.3 MJ/(m2·10a) after 1997. The decreasing trend of annual cloud cover was significant,and its decrease was 1.8%/10a. However,the low-cloud amount showed the opposite trend and increased at the rate of 3.2%/10a. The change trend of relative humidity is contrary to that of solar radiation. Relative humidity increased at the rate of 3.1%/10a from 1981 to 1997,while decreased significantly at the rate of 5.6%/10a from 1997 to 2008. The change of water vapor pressure is consistent with the change of relative humility. Low-cloud amount is the main impact factor of total solar radiation and negatively correlated to the change in total solar radiation of Nujiang basin.