f5383790-7238-4b92-836c-1167f1a5c971 eng Agricultural Stress Index (ASI) Oscar Rojas FAO oscar.rojas@fao.org N/A 2022-02-07T11:04:45 ISO 19115:2003/19139 1.0 N/A Spatial_reference EPSG 7.9 Agricultural Stress Index (ASI) Oscar Rojas > FAO oscar.rojas@fao.org N/A This index is an FAO indicator that highlights anomalous vegetation growth and potential drought in arable land during a given cropping season. It can be used to determine and characterize agricultural drought hazards. Mapping agricultural drought hazard N/A FAO, oscar.rojas@fao.org oscar.rojas@fao.org P0Y0M0DT0H0M0S https://droughtcatalogue.com/thumbnails/Global_Indices.png thumbnail https://droughtcatalogue.com/thumbnails/Global_Indices.png large_thumbnail Type: Indices Type of Drought: Agricultural Drought Application: Mapping agricultural drought hazard Extent: N/A Vegetation Health Index (VHI) N/A Aggregation period: N/A Spatial scale: N/A eng N/A 1 -180 180 -90 90 N/A N/A Various N/A N/A Not relevant -180 180 -90 90 Mapping agricultural drought hazard N/A N/A 1 Codelist omission 1 Data requirements to use: Vegetation Health Index (VHI) ; Data used: N/A; Data format: N/A; Data access: N/A; Concise description: The Agricultural Stress Index (ASI) is an index 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 pixel level. 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). Finally, each administrative area is classified according to its percentage of affected area to facilitate the quick interpretation of results by analysts. Agricultural Stress Index (ASI) This index is an FAO indicator that highlights anomalous vegetation growth and potential drought in arable land during a given cropping season. It can be used to determine and characterize agricultural drought hazards. Indices Agricultural Mapping agricultural drought hazard N/A The Agricultural Stress Index (ASI) is an index 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 pixel level. 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). Finally, each administrative area is classified according to its percentage of affected area to facilitate the quick interpretation of results by analysts. N/A FAO Oscar Rojas N/A N/A Oscar Rojas, Yanyun Li, Renato Cumani, NRL (2014). Understanding the drought impact of El Niño on the global agricultural areas: An assessment using FAO’s Agricultural Stress Index (ASI). FAO. ISSN 2071-0992. http://www.fao.org/3/a-i4251e.pdf N/A The current version of ASI has the following limitations: • The index detects extreme events of drought, which means that agricultural areas affected by moderate drought (referring to temporal intensity at pixel level) would be neglected. • It defines two cropping seasons around the globe. This works properly for most areas; however, there are regions such as Central America where there are four crop seasons in a calendar year. In ASI the first crop season does not necessarily represent the main crop season, but rather the first crop season in a calendar year. • The current version gives equal weight to all phenological phases when calculating the temporal integration without regard to the crop water requirements and their implications on crop yield reduction. N/A