Recommended Practice: Drought monitoring using the Vegetation Condition Index (VCI)

Drought monitoring is an important component in drought early warning systems. This practice shows how to monitor the impacts of meteorological drought on natural vegetation using MODIS optical satellite imagery. The practice has been developed by the Iranian Space Agency, a Regional Support Office of UN-SPIDER. It can be followed using ENVI, RStudio or Python. It is similar to the practice developed by the Universidad Federal de Santa Maria (UFSM) in Brazil, however it uses the Vegetation Condition Index (VCI) instead of the Standard Vegetation Index (SVI).


The purpose of this recommended practice is to monitor impacts of meteorological drought on natural vegetation (rain fed, range land & forest). Availability, simplicity, free of charge data, good research literature and citation, minimum requirements of inputs are main criteria, which have been considered to define the methodology.

Disaster Cycle Phase: 

  • Preparedness

Main Hazards: 

  • Drought

Test Site: 

The test site includes the following five provinces in Iran: Alborz, Tehran, Semnan, Qom, Isfahan. (See "In Detail" for maps of the test site.)


The total area of the test site amounts around 250,000 km2. The elevation within the test site ranges from 270m to 4,390m. The vegetation growth period is from May to June. The average annual rainfall amounts to 240mm. The predominant land cover is bare land and rangeland with mainly low vegetation density. Land cover of the test site also includes irrigated agriculture, rainfed agriculture, saline land, and seasonal lakes. Land cover classes with smaller occurrence include forest, orchard, and wetlands. (See "In Detail" for maps of the test site.)


The methodology as such can be applied globally. However, the choice of the months of the MODIS data will vary depending on the timing of the vegetation period.

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