The responses of vegetation water content (EWT) and assessment of drought monitoring along a coastal region using remote sensing

摘要

This article retrieved the vegetation water content equivalent water thickness (EWT) information and the relevant parameters for the land surface from full-band TM remote sensing data. The effects of surface water heat flux and surface covering on the EWT were analyzed via studies of the regional land cover status and the combined EWT with land surface parameters. This article also analyzed the roles and limitations of EWT in drought monitoring combined with classification of the regional drought and regional water stress index (RWSI). From the results, the following conclusions were reported. (1) The spatial distribution of the EWT is closely related to the vegetation, and the EWT is able to monitor the regional water conditions to a certain extent. (2) The distribution of the EWT is affected significantly by the density of vegetation cover, land surface temperature and evapo-transpiration. (3) The correlation between the NDVI (or fractional vegetation cover) and the EWT differs under different vegetation coverage conditions. (4) The evapo-transpiration of the ecological environment is closely tied to the EWT such that the changes in evapo-transpiration affect the EWT significantly. (5) The ability of the EWT to monitor regional drought is conditional, and therefore no significant indication exists that can be used to monitor moderate to severe drought conditions.