Figure 2. Precipitation (shaded, [mm/day]) and sketch of 850 hPa surface winds (arrows) over North Africa during boreal summer (June–September). Shown also is the location of the Saharan heat low (red) and the African and Tropical Easterly Jet axes. The wind and surface-pressure data are based on ERA (reanalysis) data of 1958–2001 (Uppala et al., 2005); the precipitation data are taken from the GPCP (Global Precipitation Climatology Project) dataset for the years 1979–2006 (Adler et al., 2003).