Earth Observation
GIEWS
The country level maps and graphs depict the latest 36-month period of the seasonal, vegetation and precipitation indicators. The data is presented by dekad and month.   More
All three vegetation indicators are based on 10-day (dekadal) vegetation data from the METOP-AVHRR sensor at 1 km resolution (2007 and after). Data at 1 km resolution for the period 1984-2006 are derived from the NOAA-AVHRR dataset at 16 km resolution. Precipitation estimates for all African countries (except Cabo Verde and Mauritius) are taken from NOAA/FEWSNet, while for the remaining countries data is obtained from ECMWF.
DISCLAIMERS
The boundaries and names shown and the designations used on the maps do not imply the expression of any opinion whatsoever on the part of FAO concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers and boundaries.
Viet Nam
 

Agricultural Stress Index  More
The Agricultural Stress Index (ASI) is a quick-look indicator that facilitates the early identification of cropped land with a high likelihood of water stress (drought). The Index is based on the integration of the Vegetation Health Index (VHI) in two dimensions that are critical in the assessment of a drought event in agriculture: temporal and spatial. The first step of the ASI calculation is a temporal averaging of the VHI, assessing the intensity and duration of dry periods occurring during the crop cycle at the pixel level; this calculation includes the use of crop coefficients, which introduces sensitivity of a crop to water stress during each phenological phase. The second step determines the spatial extent of drought events by calculating the percentage of pixels in arable areas with a VHI value below 35 percent (this value was identified as a critical threshold in assessing the extent of drought in previous research by Kogan, 1995). Each administrative area is classified according to the percentage of the affected area to facilitate the quick interpretation of results.
   WMS    
  First DekadSecond DekadThird Dekad
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

Drought Intensity  More
Agricultural droughts are classified by their intensity and are categorized into four classes: Extreme, Severe, Moderate or Mild. The intensity of the drought is calculated through the Weighted Mean Vegetation Health Index aggregated per GAUL 2 region, indicating that the poorer the vegetation health the more severe the drought.
   WMS  
  First DekadSecond DekadThird Dekad
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

Weighted Mean Vegetation Health Index  More
The Weighted Mean Vegetation Health Index (Weighted Mean VHI) allows the user to assess the severity of the drought from the start of the growing season, examining the vegetation health and the influence of temperature on plant conditions. The Mean VHI is an average of the dekadal VHI values over the crop growing season (from the start until the last dekad of analysis), weighted by crop coefficients (Kc), assigned to VHI values at the dekads corresponding to the Start of the Season (SOS), Maximum of the Season (MOS) and End of the Season (EOS). Crop coefficient is applied for the purpose of reflecting the crop’s water sensitivity at different phenology stages.
   WMS  
  First DekadSecond DekadThird Dekad
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

Agricultural Stress Index  More
The Agricultural Stress Index (ASI) is a quick-look indicator that facilitates the early identification of cropped land with a high likelihood of water stress (drought). The Index is based on the integration of the Vegetation Health Index (VHI) in two dimensions that are critical in the assessment of a drought event in agriculture: temporal and spatial. The first step of the ASI calculation is a temporal averaging of the VHI, assessing the intensity and duration of dry periods occurring during the crop cycle at the pixel level; this calculation includes the use of crop coefficients, which introduces sensitivity of a crop to water stress during each phenological phase. The second step determines the spatial extent of drought events by calculating the percentage of pixels in arable areas with a VHI value below 35 percent (this value was identified as a critical threshold in assessing the extent of drought in previous research by Kogan, 1995). Each administrative area is classified according to the percentage of the affected area to facilitate the quick interpretation of results.
   WMS  
  First DekadSecond DekadThird Dekad
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

Drought Intensity  More
Agricultural droughts are classified by their intensity and are categorized into four classes: Extreme, Severe, Moderate or Mild. The intensity of the drought is calculated through the Weighted Mean Vegetation Health Index aggregated per GAUL 2 region, indicating that the poorer the vegetation health the more severe the drought.
   WMS  
  First DekadSecond DekadThird Dekad
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

Weighted Mean Vegetation Health Index  More
Agricultural droughts are classified by their intensity and are categorized into four classes: Extreme, Severe, Moderate or Mild. The intensity of the drought is calculated through the Weighted Mean Vegetation Health Index aggregated per GAUL 2 region, indicating that the poorer the vegetation health the more severe the drought.
   WMS  
  First DekadSecond DekadThird Dekad
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

Agricultural Stress Index  More
The Annual ASI depicts the percentage of arable land, within an administrative area, that has been affected by drought conditions over the entire cropping season. It differs from ASI, which is based on conditions from the start of the season up to the current dekad.
   WMS    
2023 2022 2021
2020 2019 2018
2017 2016 2015
2014 2013 2012
2011 2010 2009
2008 2007 2006
2005 2004 2003
2002 2001 2000
1999 1998 1997
1996 1995 1994
1993 1992 1991
1990 1989 1988
1987 1986 1985
 
1984

Drought Intensity  More
Agricultural droughts are classified by their intensity and are categorized into four classes: Extreme, Severe, Moderate or Mild. The intensity of drought is calculated through the Weighted Mean Vegetation Health Index, indicating that the poorer the vegetation health the more severe the drought. The Annual summary of Drought Intensity allows the user to assess the overall intensity of drought for an entire growing season.
   WMS  
2023 2022 2021
2020 2019 2018
2017 2016 2015
2014 2013 2012
2011 2010 2009
2008 2007 2006
2005 2004 2003
2002 2001 2000
1999 1998 1997
1996 1995 1994
1993 1992 1991
1990 1989 1988
1987 1986 1985
 
1984

Weighted Mean Vegetation Health Index  More
The Annual Weighted Mean Vegetation Health Index (Weighted Mean VHI) allows the user to assess the overall severity of drought for an entire growing season, examining the vegetation health and the influence of temperature on plant conditions. The Annual Weighted Mean VHI takes into account the sensitivity of a crop to water stress over its growing season, and calculates the temporal impact of moisture deficits and temperature over the complete growing season.
   WMS    
2023 2022 2021
2020 2019 2018
2017 2016 2015
2014 2013 2012
2011 2010 2009
2008 2007 2006
2005 2004 2003
2002 2001 2000
1999 1998 1997
1996 1995 1994
1993 1992 1991
1990 1989 1988
1987 1986 1985
 
1984

Agricultural Stress Index  More
The Annual ASI depicts the percentage of arable land, within an administrative area, that has been affected by drought conditions over the entire cropping season. It differs from ASI, which is based on conditions from the start of the season up to the current dekad.
   WMS    
2023 2022 2021
2020 2019 2018
2017 2016 2015
2014 2013 2012
2011 2010 2009
2008 2007 2006
2005 2004 2003
2002 2001 2000
1999 1998 1997
1996 1995 1994
1993 1992 1991
1990 1989 1988
1987 1986 1985
 
1984

Drought Intensity  More
Agricultural droughts are classified by their intensity and are categorized into four classes: Extreme, Severe, Moderate or Mild. The intensity of drought is calculated through the Weighted Mean Vegetation Health Index, indicating that the poorer the vegetation health the more severe the drought. The Annual summary of Drought Intensity allows the user to assess the overall intensity of drought for an entire growing season.
   WMS  
2023 2022 2021
2020 2019 2018
2017 2016 2015
2014 2013 2012
2011 2010 2009
2008 2007 2006
2005 2004 2003
2002 2001 2000
1999 1998 1997
1996 1995 1994
1993 1992 1991
1990 1989 1988
1987 1986 1985
 
1984

Weighted Mean Vegetation Health Index  More
The Annual Weighted Mean Vegetation Health Index (Weighted Mean VHI) allows the user to assess the overall severity of drought for an entire growing season, examining the vegetation health and the influence of temperature on plant conditions. The Annual Weighted Mean VHI takes into account the sensitivity of a crop to water stress over its growing season, and calculates the temporal impact of moisture deficits and temperature over the complete growing season.
   WMS    
2023 2022 2021
2020 2019 2018
2017 2016 2015
2014 2013 2012
2011 2010 2009
2008 2007 2006
2005 2004 2003
2002 2001 2000
1999 1998 1997
1996 1995 1994
1993 1992 1991
1990 1989 1988
1987 1986 1985
 
1984

Historic Drought Frequency   More
The maps depict the frequency of severe drought in areas where: i) 30 percent of the cropped land; or ii) 50 percent of the cropped land has been affected. The historical frequency of severe droughts (as defined by ASI) is based on the entire the times series (1984-2023).
>30% of the cropland affected  
    WMS


>50% of the cropland affected  
    WMS



Historic Drought Frequency   More
The maps depict the frequency of severe drought in areas where: i) 30 percent of the cropped land; or ii) 50 percent of the cropped land has been affected. The historical frequency of severe droughts (as defined by ASI) is based on the entire the times series (1984-2023).
>30% of the cropland affected  
    WMS


>50% of the cropland affected  
  Interactive map   WMS




The seasons’ progress is based on the long-term average of vegetation phenology for each pixel. This simplification implies that the crop/pasture phenology is static and therefore the growing seasons progress at a constant rate each year.

Start of Season (SOS) indicates the early stage of crop/grass emergence, defined as the date when the rising NDVI-curve cuts the threshold NDVIs:
NDVIs=NDVImins + Ts*(NDVImax – NDVImins)
NDVImax is the NDVI at the maximum of the cycle, NDVImins is the minimum before this maximum and threshold Ts is fixed to 0.25 for all land cover types. SOS is searched leftwards from NDVImax to NDVImins.
    WMS



Maximum of Season (MOS) indicates when crop/grass foliage is fully developed, defined as the date when the NDVI is at its maximum value.
    WMS



End of Season (EOS) indicates when crop/grass has reached physiological maturity, defined as the date when the descending NDVI-curve crosses NDVIe, This date does not necessarily correspond to the harvest period.
NDVIe=NDVImine + Te*(NDVImax – NDVimine)
NDVImax is the NDVI at the maximum of the cycle, NDVImine is the minimum after this maximum and threshold Te is set to 0.75 for cropland and to 0.25 for all other land. EOS is searched rightwards from NDVImax to NDVImine.
    WMS




The seasons’ progress is based on the long-term average of vegetation phenology for each pixel. This simplification implies that the crop/pasture phenology is static and therefore the growing seasons progress at a constant rate each year.

Start of Season (SOS) indicates the early stage of crop/grass emergence, defined as the date when the rising NDVI-curve cuts the threshold NDVIs:
NDVIs=NDVImins + Ts*(NDVImax – NDVImins)
NDVImax is the NDVI at the maximum of the cycle, NDVImins is the minimum before this maximum and threshold Ts is fixed to 0.25 for all land cover types. SOS is searched leftwards from NDVImax to NDVImins.
    WMS



Maximum of Season (MOS) indicates when crop/grass foliage is fully developed, defined as the date when the NDVI is at its maximum value.
    WMS



End of Season (EOS) indicates when crop/grass has reached physiological maturity, defined as the date when the descending NDVI-curve crosses NDVIe, This date does not necessarily correspond to the harvest period.
NDVIe=NDVImine + Te*(NDVImax – NDVimine)
NDVImax is the NDVI at the maximum of the cycle, NDVImine is the minimum after this maximum and threshold Te is set to 0.75 for cropland and to 0.25 for all other land. EOS is searched rightwards from NDVImax to NDVImine.
 



Agricultural Stress Index  More
The Agricultural Stress Index (ASI) is a quick-look indicator that facilitates the early identification of cropped land with a high likelihood of water stress (drought). The Index is based on the integration of the Vegetation Health Index (VHI) in two dimensions that are critical in the assessment of a drought event in agriculture: temporal and spatial. The first step of the ASI calculation is a temporal averaging of the VHI, assessing the intensity and duration of dry periods occurring during the crop cycle at the pixel level; this calculation includes the use of crop coefficients, which introduces sensitivity of a crop to water stress during each phenological phase. The second step determines the spatial extent of drought events by calculating the percentage of pixels in arable areas with a VHI value below 35 percent (this value was identified as a critical threshold in assessing the extent of drought in previous research by Kogan, 1995). Each administrative area is classified according to the percentage of the affected area to facilitate the quick interpretation of results.
   WMS  
  First DekadSecond DekadThird Dekad
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

Drought Intensity  More
Agricultural droughts are classified by their intensity and are categorized into four classes: Extreme, Severe, Moderate or Mild. The intensity of the drought is calculated through the Weighted Mean Vegetation Health Index aggregated per GAUL 2 region, indicating that the poorer the vegetation health the more severe the drought.
   WMS  
  First DekadSecond DekadThird Dekad
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

Weighted Mean Vegetation Health Index  More
The Weighted Mean Vegetation Health Index (Weighted Mean VHI) allows the user to assess the severity of the drought from the start of the growing season, examining the vegetation health and the influence of temperature on plant conditions. The Mean VHI is an average of the dekadal VHI values over the crop growing season (from the start until the last dekad of analysis), weighted by crop coefficients (Kc), assigned to VHI values at the dekads corresponding to the Start of the Season (SOS), Maximum of the Season (MOS) and End of the Season (EOS). Crop coefficient is applied for the purpose of reflecting the crop’s water sensitivity at different phenology stages.
   WMS  
  First DekadSecond DekadThird Dekad
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

Agricultural Stress Index  More
The Agricultural Stress Index (ASI) is a quick-look indicator that facilitates the early identification of cropped land with a high likelihood of water stress (drought). The Index is based on the integration of the Vegetation Health Index (VHI) in two dimensions that are critical in the assessment of a drought event in agriculture: temporal and spatial. The first step of the ASI calculation is a temporal averaging of the VHI, assessing the intensity and duration of dry periods occurring during the crop cycle at the pixel level; this calculation includes the use of crop coefficients, which introduces sensitivity of a crop to water stress during each phenological phase. The second step determines the spatial extent of drought events by calculating the percentage of pixels in arable areas with a VHI value below 35 percent (this value was identified as a critical threshold in assessing the extent of drought in previous research by Kogan, 1995). Each administrative area is classified according to the percentage of the affected area to facilitate the quick interpretation of results.
   WMS  
  First DekadSecond DekadThird Dekad
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

Drought Intensity  More
Agricultural droughts are classified by their intensity and are categorized into four classes: Extreme, Severe, Moderate or Mild. The intensity of the drought is calculated through the Weighted Mean Vegetation Health Index aggregated per GAUL 2 region, indicating that the poorer the vegetation health the more severe the drought.
   WMS  
  First DekadSecond DekadThird Dekad
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

Weighted Mean Vegetation Health Index  More
The Weighted Mean Vegetation Health Index (Weighted Mean VHI) allows the user to assess the severity of the drought from the start of the growing season, examining the vegetation health and the influence of temperature on plant conditions. The Mean VHI is an average of the dekadal VHI values over the crop growing season (from the start until the last dekad of analysis), weighted by crop coefficients (Kc), assigned to VHI values at the dekads corresponding to the Start of the Season (SOS), Maximum of the Season (MOS) and End of the Season (EOS). Crop coefficient is applied for the purpose of reflecting the crop’s water sensitivity at different phenology stages.
   WMS  
  First DekadSecond DekadThird Dekad
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

Agricultural Stress Index  More
The Annual ASI depicts the percentage of arable land, within an administrative area, that has been affected by drought conditions over the entire cropping season. It differs from ASI, which is based on conditions from the start of the season up to the current dekad.
   WMS  
2023 2022 2021
2020 2019 2018
2017 2016 2015
2014 2013 2012
2011 2010 2009
2008 2007 2006
2005 2004 2003
2002 2001 2000
1999 1998 1997
1996 1995 1994
1993 1992 1991
1990 1989 1988
1987 1986 1985
 
1984

Drought Intensity  More
Agricultural droughts are classified by their intensity and are categorized into four classes: Extreme, Severe, Moderate or Mild. The intensity of drought is calculated through the Weighted Mean Vegetation Health Index, indicating that the poorer the vegetation health the more severe the drought. The Annual summary of Drought Intensity allows the user to assess the overall intensity of drought for an entire growing season.
   WMS  
2023 2022 2021
2020 2019 2018
2017 2016 2015
2014 2013 2012
2011 2010 2009
2008 2007 2006
2005 2004 2003
2002 2001 2000
1999 1998 1997
1996 1995 1994
1993 1992 1991
1990 1989 1988
1987 1986 1985
 
1984

Weighted Mean Vegetation Health Index  More
The Annual Weighted Mean Vegetation Health Index (Weighted Mean VHI) allows the user to assess the overall severity of drought for an entire growing season, examining the vegetation health and the influence of temperature on plant conditions. The Annual Weighted Mean VHI takes into account the sensitivity of a crop to water stress over its growing season, and calculates the temporal impact of moisture deficits and temperature over the complete growing season.
   WMS  
2023 2022 2021
2020 2019 2018
2017 2016 2015
2014 2013 2012
2011 2010 2009
2008 2007 2006
2005 2004 2003
2002 2001 2000
1999 1998 1997
1996 1995 1994
1993 1992 1991
1990 1989 1988
1987 1986 1985
 
1984

Agricultural Stress Index  More
The Annual ASI depicts the percentage of arable land, within an administrative area, that has been affected by drought conditions over the entire cropping season. It differs from ASI, which is based on conditions from the start of the season up to the current dekad.
   WMS  
2023 2022 2021
2020 2019 2018
2017 2016 2015
2014 2013 2012
2011 2010 2009
2008 2007 2006
2005 2004 2003
2002 2001 2000
1999 1998 1997
1996 1995 1994
1993 1992 1991
1990 1989 1988
1987 1986 1985
 
1984

Drought Intensity  More
Agricultural droughts are classified by their intensity and are categorized into four classes: Extreme, Severe, Moderate or Mild. The intensity of drought is calculated through the Weighted Mean Vegetation Health Index, indicating that the poorer the vegetation health the more severe the drought. The Annual summary of Drought Intensity allows the user to assess the overall intensity of drought for an entire growing season.
   WMS  
2023 2022 2021
2020 2019 2018
2017 2016 2015
2014 2013 2012
2011 2010 2009
2008 2007 2006
2005 2004 2003
2002 2001 2000
1999 1998 1997
1996 1995 1994
1993 1992 1991
1990 1989 1988
1987 1986 1985
 
1984

Weighted Mean Vegetation Health Index  More
The Annual Weighted Mean Vegetation Health Index (Weighted Mean VHI) allows the user to assess the overall severity of drought for an entire growing season, examining the vegetation health and the influence of temperature on plant conditions. The Annual Weighted Mean VHI takes into account the sensitivity of a crop to water stress over its growing season, and calculates the temporal impact of moisture deficits and temperature over the complete growing season.
   WMS  
2023 2022 2021
2020 2019 2018
2017 2016 2015
2014 2013 2012
2011 2010 2009
2008 2007 2006
2005 2004 2003
2002 2001 2000
1999 1998 1997
1996 1995 1994
1993 1992 1991
1990 1989 1988
1987 1986 1985
 
1984

Historic Drought Frequency   More
The maps depict the frequency of severe drought in areas where: i) 30 percent of the cropped land; or ii) 50 percent of the cropped land has been affected. The historical frequency of severe droughts (as defined by ASI) is based on the entire the times series (1984-2023).
>30% of the grassland affected  
    WMS


>50% of the grassland affected  
    WMS



Historic Drought Frequency   More
The maps depict the frequency of severe drought in areas where: i) 30 percent of the cropped land; or ii) 50 percent of the cropped land has been affected. The historical frequency of severe droughts (as defined by ASI) is based on the entire the times series (1984-2023).
>30% of the grassland affected  
    WMS


>50% of the grassland affected  
    WMS



The seasons’ progress is based on the long-term average of vegetation phenology for each pixel. This simplification implies that the crop/pasture phenology is static and therefore the growing seasons progress at a constant rate each year.

Start of Season (SOS) indicates the early stage of crop/grass emergence, defined as the date when the rising NDVI-curve cuts the threshold NDVIs:
NDVIs=NDVImins + Ts*(NDVImax – NDVImins)

NDVImax is the NDVI at the maximum of the cycle, NDVImins is the minimum before this maximum and threshold Ts is fixed to 0.25 for all land cover types. SOS is searched leftwards from NDVImax to NDVImins.
    WMS



Maximum of Season (MOS) indicates when crop/grass foliage is fully developed, defined as the date when the NDVI is at its maximum value.
    WMS


End of Season (EOS) indicates when crop/grass has reached physiological maturity, defined as the date when the descending NDVI-curve crosses NDVIe, This date does not necessarily correspond to the harvest period.
NDVIe=NDVImine + Te*(NDVImax – NDVimine)

NDVImax is the NDVI at the maximum of the cycle, NDVImine is the minimum after this maximum and threshold Te is set to 0.75 for cropland and to 0.25 for all other land. EOS is searched rightwards from NDVImax to NDVImine.
    WMS




The seasons’ progress is based on the long-term average of vegetation phenology for each pixel. This simplification implies that the crop/pasture phenology is static and therefore the growing seasons progress at a constant rate each year.

Start of Season (SOS) indicates the early stage of crop/grass emergence, defined as the date when the rising NDVI-curve cuts the threshold NDVIs:
NDVIs=NDVImins + Ts*(NDVImax – NDVImins)

NDVImax is the NDVI at the maximum of the cycle, NDVImins is the minimum before this maximum and threshold Ts is fixed to 0.25 for all land cover types. SOS is searched leftwards from NDVImax to NDVImins.
    WMS


Maximum of Season (MOS) indicates when crop/grass foliage is fully developed, defined as the date when the NDVI is at its maximum value.
    WMS


End of Season (EOS) indicates when crop/grass has reached physiological maturity, defined as the date when the descending NDVI-curve crosses NDVIe, This date does not necessarily correspond to the harvest period.
NDVIe=NDVImine + Te*(NDVImax – NDVimine)

NDVImax is the NDVI at the maximum of the cycle, NDVImine is the minimum after this maximum and threshold Te is set to 0.75 for cropland and to 0.25 for all other land. EOS is searched rightwards from NDVImax to NDVImine.
    WMS



NDVI Anomaly  More
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.
    
 First DekadSecond DekadThird Dekad  Monthly
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

Vegetation Condition Index  More
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.
   WMS  
 First DekadSecond DekadThird Dekad  Monthly
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

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.
   WMS       
 First DekadSecond DekadThird Dekad  Monthly
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

NDVI profile compared with LTA (1984-2015) and previous year at administrative level 1 
   

Estimated Precipitation 
The map depicts cumulative rainfall volumes over a dekad (a 10-day period). Precipitation estimates for all African countries (except Cabo Verde and Mauritius) are taken from NOAA/FEWSNet, while for the remaining countries data is obtained from ECMWF.
    
 First DekadSecond DekadThird Dekad  Monthly
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

Estimated 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.
    
 First DekadSecond DekadThird Dekad  Monthly
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

Estimated Precipitation compared with LTA and previous year at administrative level 1 
   

Accumulated Estimated Precipitation: aggregated at administrative level 1