GDO Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) Anomaly (MODIS) (version 1.3.1)

The FAPAR Anomaly indicator that is implemented in the Copernicus Global Drought Observatory (GDO) is used to detect and monitor the impacts on vegetation growth and productivity of environmental stress factors, especially plant water stress due to drought. The FAPAR Anomaly indicator is computed as deviations of the satellite-measured biophysical variable Fraction of Absorbed Photosynthetically Active Radiation (FAPAR, sometimes written as fAPAR or FPAR), composited for 10-day intervals, from its long-term mean values. FAPAR is one of the 50 so-called “Essential Climate Variables” (ECVs) that have been defined by the Global Climate Observing System (GCOS) as being both feasible for global climate observation, and important to support the work of the United Nations Framework Convention on Climate Change (UNFCCC) and the Intergovernmental Panel on Climate Change (IPCC) (Bojinski et al., 2014). FAPAR values and their anomalies have been shown to be good indicators for detecting and assessing drought impacts on plant canopies, such as agricultural crops and natural vegetation (Gobron et al., 2005), and thus provide information that is potentially useful for water and agricultural management purposes. Data considered for the GDO FAPAR Anomaly indicator are based on MODIS (Moderate-Resolution Imaging Spectroradiometer) sensor. The spatial resolution of input data is 500 m, while the resolution of data made available for download in GDO is 0.083 decimal degrees (1/12 decimal degree). The FAPAR Anomaly product comprises standardized deviations from the 2001–2016 baseline period for the data between 2001 and 2017. Starting in 2018, anomalies are computed as standardized deviation from the baseline period 2001–last-full-year. For example, FAPAR Anomaly data in 2021 are computed with a 2001–2020 baseline.