Convection over tropical Africa and the Atlantic Ocean during northern summer. Part II: modulation by easterly waves

Abstract

Using Meteosat data and ECMWF analyses, we examine easterly waves and their relation with the cloudiness over West Africa and the tropical Atlantic Ocean for three summers (June, July, August and September 1983-85). Spectral analysis of the low-level meridional wind in the 2.8-5.1 day band reveals maximum wave amplitude near the West African coast at 20°N. During August and September the wave amplitude is larger than during June and July and a secondary maximum appears around 7.5°N. -from Author