Evaluating Drought Monitoring Methods Using Remote Sensing: A Dynamic Correlation Analysis Between Heat Fluxes and Land Cover Patterns

We obtained data from remotely sensed images using a two-phase preprocessing and retrieving approach. The spatial relationships between the Normalized Difference Vegetation Index (NDVI) and heat fluxes were studied, and the capability of monitoring indices [i.e., Normalized Difference Water Index (NDWI), Temperature Vegetation Dryness Index (TVDI), and Soil Moisture Monitoring Index (SMMI)] to depict regional soil moisture and monitor regional drought was analyzed. The following conclusions were obtained. The relationships between the NDVI and heat fluxes are significantly affected by land cover; specifically, these relationships depend on the density of vegetative cover. When monitoring regional soil moisture and drought, the appropriate index (TVDI, NDWI, or SMMI) should be selected based on drought severity and other associated characteristics.