ASAP Water Satisfaction Index
Description
This document describes the Water Satisfaction Index model.
ASAP (Anomaly hotSpots of Agricultural Production) is a global early warning system being to trigger warnings about agricultural / rangeland production based on anomalies of vegetation and weather indicators. ASAP works at the level of administrative units (mostly GAUL1 level, with various exceptions) and focuses on arable land and rangelands through appropriate masks. Anomalies of relevant indicators are analysed only during the average growing season. The average growing season is retrieved at the pixel level using a simple land susfcae phenology algorithm applied to MODIS NDVI profiles.
The Water Satisfaction Index (WSI) described in the present document is an indicator of crop (or rangeland) performances based on the availability of water to the crop during the growing season. It uses a rainfall and evapotranspiration driven water balance accounting scheme to estimate water available to the plant. The use of WSI in ASAP is expected to improve the sensitivity to agricultural drought as compared to meteorological drought. This technical report describes the WSI and its functioning within ASAP.