苏丹遥感干旱指数及其适用性

摘要

针对苏丹地区利用遥感手段进行旱情监测的研究相对缺乏这一问题，该文利用 MODIS 归一化植被指数和地表温度计算植被条件指数、温度植被干旱指数和归一化植被供水指数，利用 AMSR-E 土壤湿度数据与3种干旱指数进行相关性分析，选取与土壤湿度相关性最好的干旱指数作为干旱监测的指标，对苏丹典型干湿年份的干旱进行监测。定量分析与实验结果表明：归一化植被供水指数与土壤湿度相关性最高，且与降水量存在滞后关系，3种典型植被覆盖类型下归一化植被供水指数的滞后期均为1个月；苏丹干旱主要发生在北部的撒哈拉沙漠及其边缘地区，且干旱分布受季节变化影响显著，其中春季和冬季是干旱发生的高峰期。%The research on drought monitoring using remote sensing in Sudan is rarely whereas remote sensing is an effective way of large-scale drought monitoring.In this paper,Normalized Difference Vegetation Index (NDVI)and Land Surface Temperature (LST)extracted from MODIS product were used to calculate Vegetation Condition Index (VCI), Temperature Vegetation Drought Index (TVDI)and Normalized Vegetation Supply Water Index (NVSWI).Correlation analysis between AMSR-E soil moisture data and different drought indices was carried out to select the most suitable drought indicator in Sudan.The results show that NVSWI,which has one month time-lag with precipitation for three typical land cover types,has the highest correlation with soil moisture.Furthermore,the spatial distribution of drought in Sudan was mainly in Sahara and its marginal areas whereas the temporal distribution was mainly in spring and winter.