African Easterly Waves and Rainfall Variability in Niger during the 2006 AMMA Field Campaign
Ferreira, Rosana Nieto; Rickenbach, Thomas
Dr. Ferreira showed that when Africa gets more rain, North Carolina gets more hurricanes. More than half of hurricanes, including Hurricanes Dennis and Floyd, form as African Easterly Waves (AEWs). The African Easterly Jet forms due to an interaction of warm air over the Sahara with cold air over the Gulf of Guinea, and the inter-tropical convergence zone causes convection. In this unique region, heating gets stronger and makes AEWs. Warmer air is north of the equator, not at the equator, so wind blows west. During the AMMA field campaign, NASA and MIT put radar off Africa to find out how these storms develop and if they can be used to predict Atlantic hurricanes. A total of 28 squall lines in 2006 produced 82% of all rainfall that year. AEWs propagate at two different latitudes depending on the jet. There is significant difference in the structure of systems further south and further north. More AEWs means more potential hurricanes, but factors like El Niño and wind shear will affect the production of hurricanes. Understanding the interactions between squall lines and AEWs may lead to better hurricane prediction.