The South Africa Flood and Drought Monitor is an experimental system for early warning of flood and drought conditions across the country. It has been developed by Princeton Climate Institute (PCI) in collaboration with University of Southampton and Princeton University, with funding support from UNESCO Intergovernmental Hydrology Programme (IHP). The system is based on a set of ground, satellite and modeled datasets, which are combined to provide a consistent picture of hydrological conditions close to real-time, as well as forecasts out to 7-days for floods and out to 6 months for drought.
The system is operational and is updated every day, about 1-2 days behind real-time. It runs a hydrological model over n at 5km resolution that is forced by a hybrid reanalysis-satellite dataset of precipitation and temperature. The model runoff is routed through a vector river model to produce estimates of streamflow at 1000’s of river reaches in the basin. The model outputs are used to calculate drought indices, which are also updated every day. Once a month an ensemble of seasonal forecasts is made of precipitation and temperature, which are used to drive the hydrological model out to 6 months into the future. Currently the system uses the ECMWF climate forecast system to produce the precipitation and temperature forecasts, which is one of the best performing models for the region, and has 51 ensemble members. The precipitation and temperature data are downscaled to 5km resolution and bias-corrected to remove any biases from the climate forecast model. The hydrological model outputs are used to calculate forecasts of drought indices and other statistics such as probability of drought. The forecast ensemble is represented by the mean and some other statistics of its distribution such as the 5th and 95th percentile.
The main tab of the SAF-FDM provides visualization and access to the data of the monitor. The top bar shows the name of the system and a menu with a series of tabs. The tabs provide access to the different parts of the SAF-FDM. This includes tabs for current conditions, short-term forecasts, seasonal forecasts, help, etc.
Current Conditions – This tab shows a summary of current conditions and the latest forecast.
Short-term Forecasts - This analysis tab shows detailed information on current and short-term (7-day) forecast conditions, with a focus on hydrological variables at national and district scale, and streamflow at a series of points of interest.
Seasonal Forecasts - This analysis tab shows more detailed information on current and seasonal (6-month) forecast conditions for the districts, with a focus on precipitation (hydrological forecast variables and indices are in development).
About/help – this provides background information about the SAF-FDM, as well as help information on the system and its various functions.
The following varibales and indices are included in the system: