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Application of Z - index in analysis of recent March - May drought over Rwanda

Ngarukiyimana, Jean and Tan, Guirong and Ongoma, Victor and Ogwang, Bob and Vuguziga, Floribert (2016) Application of Z - index in analysis of recent March - May drought over Rwanda. Romanian Journal of Meteorology, 13 (1-2). pp. 1-16. ISSN 2284-6220

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This study analysed recent extreme weather events in Rwanda with emphasis on drought during March-May (MAM) season using Z-index. Composite analysis identified the years 2009 and 2010 as the most recent dry and wet years respectively. Analysis of the interannual variability over the period of 1981-2010 shows that approximately 30% and 27% of the observed rainfall events were drought and flood cases, respectively. The mean MAM rainfall ranges from 90 to 180 mm in the wet year (2009), whereas during the dry year (2010), rainfall was poorly distributed both in space and time.The dry year experienced generally dry easterly winds, with almost uniformly increasing positive wind speed variation with height.The diagnosis of the evolution of Mascarene High (MH) ridge shows that during the dry year,the ridge is anomalously displaced to the west of its normal position, leading to rainfall deficit over the entire eastern Africa. The dry year exhibited a wide spread moisture divergence anomaly at low level. The noted circulation anomalies associated with the dry event are important in future monitoring of occurrence of drought.

Item Type: Journal Article
Subjects: G Geography. Anthropology. Recreation > G Geography (General)
G Geography. Anthropology. Recreation > GB Physical geography
G Geography. Anthropology. Recreation > GE Environmental Sciences
Divisions: Faculty of Science, Technology and Environment (FSTE) > School of Geography, Earth Science and Environment
Depositing User: Victor Ongoma
Date Deposited: 15 Apr 2019 04:34
Last Modified: 15 Apr 2019 04:34

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