Figure 3. Zonal wind averaged over the region 10°W to 10°E during June, July, August, and September in (m/s) based on ERA reanalysis data of 1958–2001. The shaded domains display the region with strongest ascent (darker color indicates stronger ascent). Marked also are the positions of the dynamic systems Saharan heat low (L), Intertropical Front (ITF), African Easterly Jet (AEJ), near-surface westerly monsoon flow (M), Tropical Easterly Jet (TEJ). The zonally averaged precipitation data for June to September are taken from the GPCP dataset for the years 1979–2006.