Soil Moisture Estimation and Drought Monitoring in Grape Growing Areas based on Time Series Data of MODIS
Soil Moisture(SM)is an important parameter for grape development,and accurate monitoring of SM in grape-growing areas is beneficial for scientifically guiding field irrigation and other measures,thereby pro-moting grape quality and yield.We took Jingyang County,Shaanxi Province as a typical study area,calculated six remote sensing indicators,including Normalized Difference Water Index(NDWI),Vegetation Supply Wa-ter Index(VSWI),Temperature Condition Index(TCI),Crop Water Stress Index(CWSI),etc.,based on MODIS reflectance,surface temperature,and evapotranspiration products from 2009 to 2016,preferentially se-lected indicators through sensitivity analysis of remote sensing indicators on SM,and constructed a comprehen-sive remote sensing model of SM using the classification regression tree(CART)algorithm to achieve 8-day resolution scale estimation and drought monitoring of SM at key growth stages of grape.The results showed that NDWI,VSWI and CWSI could better characterize the temporal and spatial variations of SM in the grape-growing area,and NDWI has the most timely response to SM changes and the highest correlation.The compre-hensive estimation model of SM constructed using the three preferred NDWI,VSWI and CWSI indicators achieve an R2of 0.6 or more for all time phases except 121 and 169,and an R2 of 0.8 or more for all time phases at mid-ripening stage.From 2009 to 2016,the drought in the grape-growing area of Jingyang County occurs mostly during the flowering stage and mid-ripening stage of grapes.This study can provide reference for drought monitoring in grape-growing areas.
GrapeRemote sensing drought indicatorsSoil moistureCART algorithmInversion model
万方数据
维普
