This work presents an observational study of the Intertropical Convergence Zone (ITCZ) features over the central portion of the Atlantic Ocean. The Atlantic ITCZ position, width and intensity (mean precipitation) variability for 10 years (1999-2008) was obtained objectively from pentad precipitation data. The composite method was used to obtain of the spatial distribution of precipitation, sea surface temperature (SST) and surface winds in order to identify the factors associated with ITCZ width variation. The results confirmed previous works on ITCZ position variability and showed additional information concerning the variability of the intensity and width. At monthly timescale, the ITCZ width and intensity tend to decrease when ITCZ reaches its southernmost positions (February, March and April). The annual variation amplitude was about 7° of latitude for the mean position (1°N in April to 8°N in August), 3° for the width (3° in March to 6° in October) and 3 mm.day-1 for the precipitation intensity (10 mm.day-1 in March to 13 mm.day-1 in July). The composite analysis of precipitation, SST and surface winds divergence over the Tropical Atlantic region showed that, under conditions of ITCZ position close to the average, positive width anomalies would be related to negative SST anomalies and positive convergence of surface winds, but the differences had no statistical significance.
ITCZ; precipitation; Atlantic Ocean; composite analysis
