黄河流域甘肃段地表干湿时空变化及驱动因子分析

为了探究气候变化影响下地表干湿时空变化及驱动因子，基于黄河流域甘肃段15个气象站点资料，分析了不同时间尺度SWI(地表湿润指数)的时空变化规律，采用灰色关联度法、敏感系数法和贡献特征分析定量化研究了各气象因子与SWI的变化关系。结果表明：SWI整体呈微弱上升变化，气候呈半湿润—半干旱—半湿润变化。四季由湿到干分别为夏、秋、春、冬，主要干湿气候类型依次为半湿润、半湿润、半干旱、干旱。1980s—2010s经历了湿—干—湿的变化过程。各气象因子敏感程度由高到低为P(降水量)、u(风速)、T(平均气温)、T_max(日最高气温)、n(日照时数)、T_min(日最低气温)、RH(相对湿度)。引发SWI变化的贡献大小排序为T_min,P,T,T_max,u,RH,n,其中T_min,P,u,n促使SWI增大，T,T_max,RH促使SWI降低，流域多年SWI微弱增大是T_min升高、P增大、u增加、n减少和T升高、T_max升高、RH降低...

Spatiotemporal Variation and Driving Factors of Surface Wetness Index in Gansu Section of Yellow River Basin

In order to explore the spatiotemporal variation of land surface moisture and its driving factors under the influence of climate change, based on the data of 15 meteorological stations in Gansu section of the Yellow River Basin, the spatiotemporal variation of SWI(Surface Wetness Index)of different time scales was analyzed and studied. The relationship between meteorological factors and SWI was quantitatively researched by using the gray correlation method, the sensitivity coefficient method and contribution characteristic analysis. The results showed that: the SWI had showed a slight upward change on the whole, and the climate had changed from semi-humid to semi-arid and then sub-humid; the four seasons from wet to dry were summer, autumn, spring and winter; the main dry and wet climate types were sub-humid, sub-humid, semi-arid and arid; the change process from 1980s to 2010s was from wet to dry and then to wet; the sensitivity of meteorological factors from high to low was P(precipitation), u(wind speed), T(average temperature), T_max(daily maximum temperature), n(sunshine hours), T_min(daily minimum temperature), RH(relative humidity); the order of contribution to SWI change was T_min, P, T, T_max, u, RH and n. T_min, P, u and n promoted the increase of SWI, while T, T_max and RH promoted the decrease of SWI; the slight increase of SWI over the years had been caused by the combined effects of T_min increase, P increase, u increase, n decrease, T increase, T_max increase, and RH decrease. The changes of dry and wet conditions caused by various meteorological factors resulted in the slight increase of SWI from dry to wet in Gansu section of the Yellow River Basin.