ABSTRACT
Drought is a complex climatic phenomenon of global importance with major, wide-ranging impacts to many sectors of society, including agriculture, the economy, energy, health and water, and other natural resources. Satellite-based remote sensing provides a unique perspective on drought, providing spatially distributed information that can be used in tandem with traditional, in situ-based measurements to gain a more complete view of drought conditions across the landscape. The Vegetation Health Index (VHI), which builds upon the Normalized Difference Vegetation Index (NDVI) concept and incorporates a temperature component through the use remotely sensed thermal infrared (TIR) data, is a traditional remote sensing indicator used for drought monitoring. This chapter discusses several satellite-based remote sensing tools that have been developed for drought monitoring and early warning. It presents some key examples that characterize different components of the hydrologic cycle related to drought that include vegetation status and health, Evapotranspiration (ET), soil moisture, groundwater, and precipitation.
