Real-Time Climate Information for Heat–Health Early Warning for Africa

The scientific community has now clearly recognized that short-term climate variations from weeks to months and seasons can have significant impacts on human health. In particular extreme weather events such as heat waves associated with extremely elevated air temperature and relative humidity can cause cardiovascular illnesses. The impact of climate variability on health is a global issue, but proven to be more acute in the developing world, especially Africa. The NOAA’s Climate Prediction with access to global climate observations and model data, and expertise in the monitoring and forecasting of the global climate system, provides access to operational real time climate information that can enable decision making in various socio-economic sectors including public health. This presentation first focuses on the ability of the NCEP global ensemble forecast system (GEFS) and the Climate Forecast System version 2 (CFSv2) to accurately represent heat waves in Africa. Heat waves are defined in two ways: (1) as a minimum of three consecutive days in a week with the maximum air temperature exceeding the 90^th percentile in a thirty year climatological record from 1981-2010; and (2) a heat index representing a combination of air temperature and relative humidity exceeding 40ºC for three consecutive days. Observed air temperature and relative humidity are used to calculate the observed frequency of heat wave events. Then these are compared with the GEFS and CFSv2 probabilistic forecasts of the heat waves at week2 and week3-4 time scales. Probability anomaly correlation is used to measure the performance of the NCEP models in correctly predicting heat waves. Next, we investigate the climatic characteristics of heat wave events in the Sahel. A prominent low level southerly wind flow from the Gulf of Guinea brought warm and humid air into the Sahel where mid-level atmospheric conditions were fairly stable due to a northeasterly wind flow. Because precipitation remained south in the Gulf of Guinea region, the near saturated air in the Sahel combined with high temperatures resulted in the heat waves. The predictability of the dynamics associated with the heat wave events is discussed. We further investigate the potential use of this information to map heat risks in the Sahel and the benefit of working with the Ministries of Health to prepare experimental heat health early warnings.