Abstract. Early warning of weather related hazards enables farmers, policy makers and aid agencies to mitigate their exposure to risk. We present a new operational framework, Tropical Applications of Meteorology using SATellite data and ground based measurements-AgricuLtural EaRly warning sysTem (TAMSAT-ALERT), which facilitates monitoring of meteorological risk to agriculture. TAMSAT-ALERT combines information on land surface properties, seasonal forecasts and historical weather into quantitative assessments of the likelihood of adverse weather-related outcomes, such as low yield. This 15 article describes the TAMSAT-ALERT framework and demonstrates its application to risk assessment for low maize yield in Northern Ghana. The modular design of TAMSAT-ALERT enables it to accommodate any impact/land surface model driven with meteorological data, and hence to enhance rather than displace existing operational systems. The implementation described here uses the well-established General Large Area Model for annual crops (GLAM) to provide probabilistic assessments of the meteorological hazard to maize yield in northern Ghana throughout the growing season. The results show 20 that climatic risk to yield is poorly constrained at the beginning of the season, but as the season progresses, the uncertainty rapidly reduces. The TAMSAT-ALERT methodology implicitly weights forecast and observational inputs according to their relevance to the metric being assessed. TAMSAT-ALERT can thus be used as a test-bed for the value of probabilistic seasonal forecast information. Here, we show that in northern Ghana, the regional tercile seasonal forecasts of cumulative rainfall and mean temperature, which are routinely issued to farmers, are of limited value for decision making. 25
IntroductionMany African people depend on rain-fed agriculture, and are thus vulnerable to drought, and other weather-related hazards.Anticipation of hazard enables farmers and aid agencies to plan ahead, averting disaster (Boyd et al., 2013). Here, we present a new framework for early warning of high meteorological risk to agriculture, the Tropical Applications of Meteorology using SATellite data and ground based measurements-AgricuLtural EaRly warning sysTem (TAMSAT-ALERT). TAMSAT-30 ALERT integrates assessment of climatological weather-related risk, with forecasts and real-time monitoring of environmental conditions. The framework is intended to be a decision support system, which when combined with socio-economic assessments, can be used by governmental agencies and NGOs to help farmers manage agricultural risk.The need for timely information on agricultural risk has motivated the development of a number of drought early warning systems and decision support platforms. The Rainwatch-AfClix early warning system (RWX), for example, provides time 35 series of cumulative rainfall, which are compared against historical time years. Users value the facility to compare the current season against past years, finding that it enables them to intuitively gauge risk (Ta...