Richard Marcelaine and Xubin Zeng1
Droughts in the West African Sahel cause devastating consequences to inhabitants of the region. Predicting when droughts will occur, however, continues to elude scientists. This research analyzes the relation between the African easterly jet (AEJ), the tropical easterly jet (TEJ), and seeks to explore the predictability for precipitation in the West African Sahel region. To evaluate the relation between the AEJ and TEJ, five anomalously wet years and five anomalously dry years were identified using the Sahel Precipitation Index. The composites were then plotted using National Centers for Environmental Prediction reanalysis data sets. During wet (dry) years, the TEJ revealed a high (low) core velocity and the AEJ responded with a poleward (equatorward) shift. The same relation was also revealed when using the TEJ at its generation over India. A weak trend was shown in a regression analysis when using TEJ’s core speed at its origin during June, and the average precipitation during the summer months. The results of this research suggest the TEJ’s core velocity at its generation may assist in developing a dynamic drought prediction model for the West African Sahel.
1Department of Hydrology and Atmospheric Sciences, The University of Arizona, Tucson, AZ