Intraseasonal Variability of the West African Monsoon

Colorado State University, Fort Collins CO

Investigators

Abstract

The intraseasonal variability of the West African monsoon system will be examined during boreal summer using a multidecadal data record. The research plan is as follows: - Characterize and understand observed boreal summer variability over sub-Saharan West Africa on intraseasonal timescales. - Determine if and how such intraseasonal variability is connected to global modes of variability such as convectively coupled equatorial waves and the Madden-Julian oscillation. - Determine if intraseasonal flow variations are associated with modulation of African easterly wave activity, as suggested by previous studies. Most importantly, examine intraseasonal variations in the energy budget of synoptic waves and also the large-scale potential vorticity gradient to determine why such intraseasonal modulation may occur. - Determine if intraseasonal variability in winds and precipitation over sub-Saharan Africa is connected to a modulation of Atlantic tropical cyclogenesis. Also determine the extent to which the Atlantic Inter-Tropical Convergence Zone (ITCZ) to the west of Africa is affected. - Determine if summertime intraseasonal variability over sub-Saharan Africa is predictable. The work complements ongoing work in the African Monsoon Multidisciplinary Analysis (AMMA) project. A comparison to results derived from the denser spatial and temporal sampling, but shorter record length, of AMMA will prove particularly useful. Broader impacts: This project will fund the graduate studies of Paula White at Oregon State University (OSU). Ms. White has been a graduate student at OSU since Winter Quarter of 2005. She is a self - motivated and hardworking student, and many (if not most) of the ideas for this project are her own. She will present her research results at scientific meetings and through publications. The research may produce information that will improve weather and cyclone prediction in the West African- eastern tropical Atlantic region.