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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. Illustration of the ASI computations.

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.

The indicator depicts the development of crops/pastures during the growing season. For any dekad (a 10-day period), the map indicates how far the season has progressed, represented by a value between 0 and 100 percent (i.e. 50 percent is the mid-point of the growing season). 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.

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.

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.

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.

The indicator depicts the development of crops/pastures during the growing season. For any dekad (a 10-day period), the map indicates how far the season has progressed, represented by a value between 0 and 100 percent (i.e. 50 percent is the mid-point of the growing season). 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.

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.

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.

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 (1984-2024).

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 (1984-2024).

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.

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.

The indicator depicts the development of crops/pastures during the growing season. For any dekad (a 10-day period), the map indicates how far the season has progressed, represented by a value between 0 and 100 percent (i.e. 50 percent is the mid-point of the growing season). 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.

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.

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.

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.

The indicator depicts the development of crops/pastures during the growing season. For any dekad (a 10-day period), the map indicates how far the season has progressed, represented by a value between 0 and 100 percent (i.e. 50 percent is the mid-point of the growing season). 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.

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.

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.

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.

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.

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 (1984-2024).

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 (1984-2024).