Online Drought Indicators and Indices

Normalized Difference Vegetation Index (NDVI)

 

Index name: Normalized Difference Vegetation Index (NDVI).

Ease of use: Green.

Origins: Developed from work done by Tarpley et al. and Kogan with the National Oceanic and Atmospheric Administration (NOAA) in the United States.

Characteristics: Uses the global vegetation index data, which are produced by mapping 4 km daily radiance. Radiance values measured in both the visible and near-infrared channels are used to calculate NDVI. It measures greenness and vigour of vegetation over a seven-day period as a way of reducing cloud contamination and can identify drought-related stress to vegetation.

Input parameters: NOAA AVHRR satellite data.

Applications: Used for identifying and monitoring droughts affecting agriculture.

Strengths: Innovative in the use of satellite data to monitor the health of vegetation in relation to drought episodes. Very high resolution and great spatial coverage.

Weaknesses: Data processing is vital to NDVI, and a robust system is needed for this step. Satellite data do not have a long history.

Resources: The literature describes the methodology and calculations. NDVI products are available at NOAA STAR – Global Vegetation Health Products webpage. Global NDVI data can be found at the Copernicus Global Land Service, while European NDVI data are accessible at The World Data Center for Remote Sensing of the Atmosphere. Additional resources are available at the Flood and Drought portal developed by GEF, UN Environment, IWA and DHI.

References:
Kogan, F.N., 1995: Droughts of the late 1980s in the United States as derived from NOAA polar-orbiting satellite data. Bulletin of the American Meteorology Society, 76(5):655–668. DOI: 10.1175/1520-0477(1995)076<0655:DOTLIT>2.0.CO;2.

Tarpley, J.D., S.R. Schneider and R.L. Money, 1984: Global vegetation indices from the NOAA-7 meteorological satellite. Journal of Climate and Applied Meteorology, 23:491–494. DOI: 10.1175/1520-0450(1984)023<0491:GVIFTN>2.0.CO;2.

Currently used by: Chile, Pakistan.

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