Earth Observation
GIEWS
Non-seasonal indicators (NDVI anomaly, VCI and VHI) provide alternative measures of vegetation health. These indices measure vegetation conditions relative to historical norms rather than in absolute terms and can be used to monitor the areas where vegetation may be stressed. A high value indicates that vegetation is healthier or less stressed than is typical for that location and time of year, while a low value implies the opposite. For example, a high value in a sparsely vegetated environment, such as a savannah, reflects above-average vegetation performance for that setting, not dense or lush vegetation.

On this website, NDVI anomaly, VCI, and VHI are presented in map format, while absolute NDVI values (zonal statistics at GAUL level 1) are shown in graph format. Users can also download NDVI and VHI zonal statistics in tabular form or explore the data through a dynamic data viewer.

Precipitation indicators, as one of core drivers of crop growth, provides a global analysis of both absolute (mm) and relative (%) rainfall levels per dekad, in addition to long-term average precipitation levels (mm). These indicators complement the NDVI-based vegetation metrics.

We recommend that users rely primarily on seasonal indicators (Agricultural Stress Index, Drought Intensity and Weighted Mean VHI) for agricultural monitoring. If significant discrepancies with local conditions are observed in the seasonal indicators, these are likely due to limitations in the crop phenology and/or crop mask data. In such cases, users may wish to refer to the non-seasonal vegetation indicators. Please visit FAQs for further information.
YearDekad
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NDVI anomaly 
The Normalized Difference Vegetation Index (NDVI) measures the “greenness” of ground cover and is used as a proxy to indicate the density and health of vegetation. NDVI values range from +1 to -1, with high positive values corresponding to dense and healthy vegetation, and low and/or negative NDVI values indicating poor vegetation conditions or sparse vegetative cover. The NDVI anomaly indicates the variation of the current dekad to the long-term average, where a positive value (for example 20 percent) would signify enhanced vegetation conditions compared to the average, while a negative value (for instance -40 percent) would indicate comparatively poor vegetation conditions. Here NDVI anomaly is presented in map format, while absolute NDVI values (zonal statistics at GAUL level 1) are present in graph format (NDVI profile compared to long term average). Users can also download NDVI zonal statistics in tabular form or explore the data through a dynamic data viewer.
   


Vegetation Condition Index 
The Vegetation Condition Index (VCI) evaluates the current vegetation health in comparison to the historical trends. The VCI relates current dekadal Normalized Difference Vegetation Index (NDVI) to its long-term minimum and maximum, normalized by the historical range of NDVI values for the same dekad. The VCI was designed to separate the weather-related component of the NDVI from the ecological element.
  WMTS  


Vegetation Health Index 
The Vegetation Health Index (VHI) illustrates the severity of drought based on the vegetation health and the influence of temperature on plant conditions. The VHI is a composite index and the elementary indicator used to compute the ASI. It combines both the Vegetation Condition Index (VCI) and the Temperature Condition Index (TCI). The TCI is calculated using a similar equation to the VCI, but relates the current temperature to the long-term maximum and minimum , as it is assumed that higher temperatures tend to cause a deterioration in vegetation conditions. A decrease in the VHI would, for example, indicate relatively poor vegetation conditions and warmer temperatures, signifying stressed vegetation conditions, and over a longer period would be indicative of drought. The VHI images are computed for the two main seasons and in three modalities: dekadal, monthly and annual.
  WMTS    


YearDekad
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Estimated Precipitation 
The map depicts cumulative rainfall volumes over a dekad (a 10-day period). Precipitation estimates are rainfall forecasts and are obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF).
   


Precipitation Anomaly


Estimated Precipitation (long term average)


YearMonth
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NDVI anomaly 
The Normalized Difference Vegetation Index (NDVI) measures the “greenness” of ground cover and is used as a proxy to indicate the density and health of vegetation. NDVI values range from +1 to -1, with high positive values corresponding to dense and healthy vegetation, and low and/or negative NDVI values indicating poor vegetation conditions or sparse vegetative cover. The NDVI anomaly indicates the variation of the current dekad to the long-term average, where a positive value (for example 20 percent) would signify enhanced vegetation conditions compared to the average, while a negative value (for instance -40 percent) would indicate comparatively poor vegetation conditions.


Vegetation Condition Index 
The Vegetation Condition Index (VCI) evaluates the current vegetation health in comparison to the historical trends. The VCI relates current dekadal Normalized Difference Vegetation Index (NDVI) to its long-term minimum and maximum, normalized by the historical range of NDVI values for the same dekad. The VCI was designed to separate the weather-related component of the NDVI from the ecological element.
  WMTS  


Vegetation Health Index  More
The Vegetation Health Index (VHI) illustrates the severity of drought based on the vegetation health and the influence of temperature on plant conditions. The VHI is a composite index and the elementary indicator used to compute the ASI. It combines both the Vegetation Condition Index (VCI) and the Temperature Condition Index (TCI). The TCI is calculated using a similar equation to the VCI, but relates the current temperature to the long-term maximum and minimum , as it is assumed that higher temperatures tend to cause a deterioration in vegetation conditions. A decrease in the VHI would, for example, indicate relatively poor vegetation conditions and warmer temperatures, signifying stressed vegetation conditions, and over a longer period would be indicative of drought. The VHI images are computed for the two main seasons and in three modalities: dekadal, monthly and annual.
  WMTS  


YearMonth
Select:     

Estimated Precipitation 
The map depicts cumulative rainfall volumes over a dekad (a 10-day period). Precipitation estimates are rainfall forecasts and are obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF).


Precipitation Anomaly 
The map illustrates the difference between the current rainfall volume and the average level. Rainfall levels are compared with the Long-Term Average (LTA), which refers to the period 1989-2015. Warmer colours identify areas which have received lower-than-average rainfall, while colder colours are given to areas where precipitation has been above average.


Estimated Precipitation (long term average)