1982～2010年气候与土地利用变化对无定河流域干旱指数变化的影响

基于19822010年无定河流域的遥感影像、气象和土地利用数据,利用Priestley-Taylor公式计算出潜在蒸散发,进而得到干旱指数,将各气象因子与干旱指数差值进行叠加、逐象元相关分析,得到了无定河流域19822010年干旱指数的时空变化,并分析了气候和土地利用变化对干旱指数变化的影响。结果显示:（1）1982年、2010年干旱指数分别为2.01和2.13,总体趋势是趋干旱的;（2）干旱指数2.0以下的区域迅速减少,2.15以上的区域明显扩张;（3）干旱指数均呈现增加趋势,显著增加的区域集中于无定河流域中游和下游地区;（4）干旱指数变化同气温、水汽压、净辐射的变化成正相关,同降水量变化成负相关;（5）各种土地利用类型的干旱指数均呈现增长趋势,但是增长的幅度有所不同:林地>耕地>草地>建筑用地>水域>未利用地。（6）土地利用对干旱指数平均值的影响非常微弱,干旱指数的变化主要是由于气候变化导致的。

Effects of Climate and Land Use Change on Changes of Aridity Index in Wudinghe River Basin, China: 1982 to 2010

Based on the remote sensing images, meteorological and land use data of the Wudinghe River basin during 1982-2010, we used Priestley-Taylor formula to calculate potential evapotranspiration, then got aridity index of this period. With overlaying the meteorological factors and aridity index difference, pixel-by-correlation analysis, the aridity index variations over spatial and tempo - ral in the study area during this period were analyzed, and the influence of the climate and land use variations on the aridity index changes was studied. The results show that: (1) The aridity indexes of the year 1982 and 2010 were 2.01and 2.13 respectively. The trend was drought; (2) There was a rapid decline in the regional aridity index of 2.0 or less, while a significant expansion of the area above 2.15; (3) It showed an increasing trend with the aridity index, a significant increase in the region focused on the middle reaches and downstream areas of the Wudinghe River basin; (4) The variation of aridity index was positively correlated with the changes in temperature, vapor pressure and net radiation, while negatively correlated with changes in precipitation; (5) The aridity index of all the land use types showed a growth trend, but the growth rate was different: forestland > cultivated Land > pasture > building land> water body > unused land; (6) The impact of land use to the average aridity index was very weak, and the variation of aridity index was mainly caused by climate change.