The African Flood and Drought Monitor provides near real-time monitoring and forecasting of hydrological conditions for operational and research use over Africa. The AFDM was developed by Princeton University and Princeton Climate Institute, in collaboration with USACE’s International Center for Integrated Water Resources Management (ICIWaRM) and UNESCO’s G-WADI major initiative. It is a state-of-the-art tool, now maintained and updated by the University of Southampton, that combines historical and near real-time monitoring of hydrologic conditions plus short-term and seasonal forecasting. It uses available satellite remote sensing and in-situ information and a hydrologic modeling platform to track changes in hydrological conditions and provide early warning of extreme events, and delivers this information through an intuitive web-based user interface. The monitor has been used to study and improve water security and regional security throughout Africa through studies of drought resilience, infrastructure impacts, epidemics, migration, and child health. A Latin American Flood and Drought Monitor has also been available since 2015, but is currently inactive.
As described in a Bulletin of the American Meteorological Society article, the AFDM comprises four parts:
1) A historic reconstruction (1960 – 2020) of hydrology forced by a merged reanalysis/observational meteorological data set; this forms the climatology against which current hydrological conditions are compared.
2) Real-time monitoring (2021 – present) driven by satellite precipitation and atmospheric model analysis data that tracks conditions in near real-time, and is updated every day.
3) Short-term forecasts out to 10-days focused on early-warning of flood conditions and meteorological extremes (e.g. extreme temperatures), which are also updated every day.
4) Seasonal forecasts out to 6 months focused on early-warning of drought conditions, which are updated every month.
The hydrological data are calculated using the Variable Infiltration Capacity (VIC) land surface hydrological model (Liang et al., 1994), which is run at a daily time step and 5km spatial resolution for the whole of Africa.
Drought is estimated primarily in terms of low soil moisture, which is given as a drought index based on soil moisture percentiles. Other drought indices based on low precipitation and streamflow are also provided. Floods are estimated based on high streamflow percentile values calculated across a high-definition river network. The drought and flood indices (and all hydrological variables and meteorological forcings) are available for the entire historic record up to real-time. The variables include: simulated discharge, precipitation, evapotranspiration, surface runoff, baseflow, and the soil moisture. These data are also provided as averages over countries and major basins.
The development of the AFDM was one of the accomplishments cited in the awarding of the Sixth Prince Sultan Bin Abdulaziz International Prize for Water (2014) to its developers at Princeton University, Eric Wood and Justin Sheffield. The AFDM has already been applied to applied studies of drought resilience, impact of irrigation dams, human migration, and health and epidemiology.