遥感干旱指数在金沙江流域干旱监测中的适用性研究

Applicability of Remote Sensing Drought Index in DroughtMonitoring of Jinsha River Basin

利用2015—2020年金沙江流域MODIS数据和流域内29个气象站1991—2020年月降水、气温资料,研究不同遥感干旱指数在金沙江流域的适用性,这些指数包括温度状态指数(temperature condition index,TCI)、温度植被干旱指数(temperature vegetation dryness index,TVDI)、植被状态指数(vegetation condition index,VCI)、植被供水指数(vegetation supply water index,VSWI)和标准化降水蒸散指数(standardized precipitation evapotranspiration index,SPEI)。结果表明:TCI与TVDI、VSWI与TCI、VSWI与TVDI、VSWI与VCI各月的相关性均较为显著。TVDI与SPEI和TCI与SPEI全年相关性较好。SPEI与VSWI相关性在1月、10月较低,其余月份均相关性较好。SPEI与VCI在1—3月相关性较低,其余月份均相关性较好。根据4种遥感干旱指数与SPEI的相关性分析,建议金沙江上游地区选用TVDI进行干旱监测;金沙江流域中游地区选用VSWI进行干旱监测;若使用VCI进行干旱监测,区域应集中于金沙江中游地区,且相关月份应集中于4—12月。金沙江流域下游地区选用TCI进行干旱监测。

Based on the MODIS data of Jinsha River Basin from 2015 to 2020 and the monthly precipitation and temperature data of 29 meteorological stations in the basin from 1991 to 2020,the applicability of different remote sensing drought indexes in Jinsha River Basin is studied.These indexes include temperature condition index(TCI),temperature vegetation drought index(TVDI),and vegetation condition index(VCI).The results of vegetation supply water index(VSWI)and standardized precipitation evapotranspiration index(SPEI)show that there are significant correlations between TCI and TVDI,VSWI and TCI,VSWI and TVDI,VSWI and VCI in each month.The correlations between TVDI and SPEI and between TCI and SPEI were statistically significant throughout the year.The correlation between SPEI and VSWI was low in January and October,and significant in other months.The correlation between SPEI and VCI is low from January to March,and the correlation is significant in other months.According to the correlation analysis of four remote sensing drought indexes and SPEI,it is suggested that TVDI should be used for drought monitoring in the upper reaches of Jinsha River;VSWI for drought monitoring in the middle reaches of Jinsha River Basin;If VCI is used for drought detection,the area should be concentrated in the middle reaches of Jinsha River,and the relevant months should be from April to December.TCI is selected for drought monitoring in the lower reaches of Jinsha River Basin.