基于GIS的重庆市复杂地形干旱精细化空间分布

Study on Drought Fine Distribution over Rugged Terrains Based on GIS

利用ArcGIS结合数字高程模型DEM(1∶25万),在分析地理因子对干旱分布影响的同时,考虑了降水量对干旱分布的影响;针对不同时段降水量对干旱影响的差异,选择关键时段降水量,结合地理因子建立了各季节干旱分布的回归统计模型;使用该模型计算了重庆市各季节干旱频率的空间分布。为了对模型计算结果进行验证,本文还采用常用的反距离平方插值法对干旱频率进行空间插值,并将插值结果和回归统计结果与实际观测值进行比较。结果表明:综合考虑降水和地理因子的回归统计方法要明显优于反距离平方插值法,能够较好地反映重庆市复杂地形下干旱频率的空间分布趋势。

In order to simulate the spatial distribution of complex terrain better, the 1 ： 250000 DEM （digital elevation model） was used with the help of ArcGIS. At the same time, precipitation was also taken into account. Due to the precipitation of different time had difference impacts on drought, so the key periods of precipitation was selected. Combined with the geographical factor, the regression-statistical model was established, which to simulate the spatial distribution of seasonal drought frequency in Chongqing. In order to verify the model, this article also used inverse distance square interpolation method to get the spatial distribution of drought frequency, which was used to compare the results of regression-statistical model with the observations. The compare results showed that the regression-statistical method considering geographical factor and precipitation was significantly better than the inverse distance square interpolation method, and could better reflect the spatial distribution trends of drought frequency over the rugged areas in Chongqing.