Diagnosis of floods/drought and their associated circulation anomaly over Malawi
Francis Alexander
Published by: Nanjing University of Information Science & Technology ; 2017
Floods and droughts are one of extreme weather climatic events that result in loss of life and property in Malawi. However, a well detailed knowledge of understanding of previous extreme climatic events and their associated impacts can be a precautionary in reducing their impacts, as it will help to project future events timely. Therefore this paper presents an analysis of Dec-Feb seasonal flood/drought events and their associated circulation anomalies over Malawi. The DJF seasonal flood/drought was studied using monthly data from 9 selected stations for the period of 1978-2010. A set of regional flood drought indices with a scheme of classifying their severity was employed to classify the flood/drought into seven different grades using the Z-Index. The results revealed that 2 years 1997 and 2007 the area experienced severe floods, while extreme drought years were 1992 and 2000 . Wet years were associated with convergence at low level and divergence at upper level mostly over the equatorial western Indian Ocean as well as over the area of study. Dry years had divergence at low level and convergence at upper level especially western Indian ocean and the area of study .The SST showed that dry years were manifested with negative anomalies over equatorial western Indian ocean and the equatorial Atlantic ocean, while a strong positive anomaly in equatorial pacific Ocean. Wet years were characterized by positive anomaly south of Madagascar in the Indian Ocean, and a negative anomaly in the Pacific Ocean. The EOF1 showed that the spatial distribution of rainfall during DJF is relatively uniform, positive loadings dominate all over the area with strong positive loading in the southern region and a weak positive loading over northern region and south of Lake Malawi.
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Language(s): English
Format: Digital (Available online for logged-in users)Tags: Flood ; Drought ; Malawi ; Thesis - WMO Fellowship Division 
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