Early warning of weather-related hazard is crucial for a range of decision makers (policy makers to local farmers) to mitigate their exposure to risk. Multiple sources of environmental information, such as remotely-sensed and ground-based rainfall and temperature observations, model reanalyses and meteorological forecasts, are available that can be used to support such decision making.
TAMSAT-ALERT, which stands for TAMSAT-AgricuLtural EaRly warning sysTem, is a monitoring and decision support tool that makes optimal use of such data streams to assess and anticipate the risk of meteorological hazards to agriculture. Given the (1) historical weather conditions (climatology), (2) state of the land surface, (3) evolution of the growing season and (4) meteorological forecast (optional), the TAMSAT-ALERT framework attempts to assess what is the risk of some adverse event occurring? The risk is estimated using historical and present-day observations of an environmental metric relevant to the adverse event in question. Currently, TAMSAT-ALERT can estimate risk for cumulative rainfall (soil moisture will be available end of Jan 2019).
Various applications of TAMSAT-ALERT are currently being piloted across Africa, including drought prediction at five locations in Ghana. The plot below shows an ensemble forecast for total soil moisture for Tamale, a location in northern Ghana. The red vertical line is the day of the forecast, the green vertical lines indicate the main growing season and the grey polygon shows the climatological range. The thin black lines how ensemble forecasts/best guess historical estimates.
TAMSAT-ALERT translates the time series shown in the plot into metrics of risk, which can be used by governmental and non-governmental organisations for planning and decision support.