JLE

Science et changements planétaires / Sécheresse

MENU

Influence of the two regimes of easterly waves on the water vapor flux in West Africa during the summer of 1981 Volume 18, issue 2, Avril-Mai-Juin 2007

Figures

See all figures

Author
Département de physique, Faculté des sciences, Université de Douala, BP 24157, Douala, Cameroun

This work is focused on the study of the water vapor flux in connection with the African wave and the 6-9-day easterly wave over West Africa. The largest oscillations of the zonal water vapor flux associated with the two regimes of easterly waves appear around the Inter Tropical Convergence Zone (ITCZ). The distribution of the meridional water vapor flux displays large oscillations around the ITCZ and towards the equator, thereby pointing out to the contribution of the two regimes to water vapor transports across the equator. The study of the modulation of these fluxes shows that the two regimes increase water vapor by the monsoon flux, mainly between latitudes 5°N-16°N, with maximum oscillations towards the ICTZ, in the layers 850-700 and 700-500 hPa, while the zonal water vapor flux is east to west at these levels. The quantities of west-to-east flux injected in these layers by the two regimes of easterly waves are nearly equal to those of the monsoon flux in the 1,000-850 hPa layer. The modulation of the zonal (meridional) water vapor flux is more marked in the 6-9-day (3-5days) wave than in the 3-5-day (6-9 days) wave, mainly towards the ITCZ.