A five-year analysis of MODIS NDVI and NDWI for grassland drought assessment over the central Great Plains of the United States

Geophysical research letters, vol. 34, L06407, doi:10.1029/2006GL029127:

This article addresses grassland drought assessment within the United States through the monitoring of normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) data by moderate resolution imaging spectroradiometer (MODIS). It investigates and compares satellite-derived methods for measuring and monitoring drought in grasslands over the central Great Plains of the central United States, specifically for the Flint Hills of Kansas and Oklahoma.

The study includes: (1) the development of a regional climatological time-series database (2001–2005) of MODIS-derived NDVI and NDWI; (2) an evaluation of the relationship between NDVI, NDWI, and climate conditions over grassland; (3) an investigation of additional drought information provided by NDWI versus NDVI, based on a 5-year comparison of the two indices; and (4) the generation of a new vegetation drought index, the normalized difference drought index (NDDI), to investigate drought conditions over the grasslands of the Flint Hills ecoregion.