Evaluation of MODIS NDVI and NDWI for vegetation drought monitoring using Oklahoma Mesonet soil moisture data

Authors

Yingxin Gu, ASRC Research and Technology Solutions, USGS Earth Resources Observation and Science Center
Eric Hunt, University of Nebraska - Lincoln
Brian Wardlow, University of Nebraska - LincolnFollow
Jeffrey B. Basara, University of Oklahoma
Jesslyn F. Brown, USGS Earth Resources Observation and Science CenterFollow
James P. Verdin, USGS Earth Resources Observation and Science Center

Document Type

Article

Date of this Version

2008

Citation

Gu, Y., E. Hunt, B. Wardlow, J. B. Basara, J. F. Brown, and J. P. Verdin (2008), Evaluation of MODIS NDVI and NDWI for vegetation drought monitoring using Oklahoma Mesonet soil moisture data, Geophys. Res. Lett., 35, L22401, doi:10.1029/2008GL035772.

Comments

Copyright 2008 by the American Geophysical Union.

Abstract

The evaluation of the relationship between satellitederived vegetation indices (normalized difference vegetation index and normalized difference water index) and soil moisture improves our understanding of how these indices respond to soil moisture fluctuations. Soil moisture deficits are ultimately tied to drought stress on plants. The diverse terrain and climate of Oklahoma, the extensive soil moisture network of the Oklahoma Mesonet, and satellitederived indices from the Moderate Resolution Imaging Spectroradiometer (MODIS) provided an opportunity to study correlations between soil moisture and vegetation indices over the 2002–2006 growing seasons. Results showed that the correlation between both indices and the fractional water index (FWI) was highly dependent on land cover heterogeneity and soil type. Sites surrounded by relatively homogeneous vegetation cover with silt loam soils had the highest correlation between the FWI and both vegetation-related indices (r~0.73), while sites with heterogeneous vegetation cover and loam soils had the lowest correlation (r~0.22).