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

Yingxin Gu, Jesslyn F. Brown, James P. Verdin, Brian Wardlow

Research output: Contribution to journalArticlepeer-review

374 Scopus citations

Abstract

A five-year (2001-2005) history of moderate resolution imaging spectroradiometer (MODIS) normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) data was analyzed for grassland drought assessment within the central United States, specifically for the Flint Hills of Kansas and Oklahoma. Initial results show strong relationships among NDVI, NDWI, and drought conditions. During the summer over the Tallgrass Prairie National Preserve, the average NDVI and NDWI were consistently lower (NDVI < 0.5 and NDWI < 0.3) under drought conditions than under non-drought conditions (NDVI>0.6 and NDWI>0.4). NDWI values exhibited a quicker response to drought conditions than NDVI. Analysis revealed that combining information from visible, near infrared, and short wave infrared channels improved sensitivity to drought severity. The proposed normalized difference drought index (NDDI) had a stronger response to summer drought conditions than a simple difference between NDVI and NDWI, and is therefore a more sensitive indicator of drought in grasslands than NDVI alone.

Original languageEnglish (US)
Article numberL06407
JournalGeophysical Research Letters
Volume34
Issue number6
DOIs
StatePublished - Mar 28 2007

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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