Developing a Composite Indicator with Landsat Thematic Mapper/Enhanced Thematic Mapper Plus Images for Drought Assessment in a Coastal Urban Region

The early quantitative indices based on climatic and meteorological observations include the Palmer drought severity index (PDSI), rainfall anomaly index, and Palmer crop moisture index. Drought measurement relies on biophysical parameters such as vegetation indices (VIs), land surface temperature (LST), soil moisture, albedo, and evapotranspiration (ET). Various satellite-derived VIs have been developed to quantitatively assess vegetation covers using spectral measurements. The uses of red and near-infrared (NIR) spectral bands of the sensors on board satellites are well suited for assessing vegetation covers. This chapter presents several composite indicators of TVDIs (TVDI_NDVI, TVDI_ANDVI, TVDI_SAVI, and TVDI_MSAVI) that were designed to combine temperature with different VIs (NDVI, ANDVI, SAVI, and MSAVI) for comparisons. It leads to the test of TVDI adaptation and application potential for monitoring regional drought holistically. Noise reduction is necessary for remotely sensed images, especially for the thermal infrared band. Noise may affect the retrieval of LST, sensible heat flux, and latent heat flux.