Abstract This study aims to identify the main causes of extreme rainfall events specifically recent ones that occurred in Central East Africa, which seriously affected the western part of Burundi causing 77 deaths, destruction of infrastructures, loss of properties and hectares of lands in February, 2014. To understand underlying issues about extreme rainfall occurrence and its key drivers, the present study investigated two distinct extreme rainfall events that caused massive losses in the western part of Burundi on November 11th, 2009 and February 9th, 2014. Different datasets have been used to depict which one captured reliable information of the two extreme rainfall events investigated. Analysis of different weather parameters was conducted using the European Centre for Medium-Range Weather Forecast (ECMWF) datasets. The Weather Research and Forecasting (WRF) Model was also employed to analyse different parameters over different periods, thus prior, during, and after the occurrence of an extreme rainfall event. It was found that the two distinct rainfall events were induced by the combination of local convection enhanced by moist air from the Congo basin and abnormal conditions in the mid-upper layer. Instabilities in the lower and mid-upper layers mainly emanated from the changes in geopotential height and wind circulation. Local physical factors especially the topography and the presence of the Lake Tanganyika localized in the Western Rift Valley of Africa enhanced local convection which triggered rapid condensation that induced a heavy rainfall over the western part of Burundi. Weather conditions vary depending on the time or season of occurrence of the extreme rainfall events. This study will propel future studies on historical diagnosis and forecasting of extreme weather events over Burundi. It will also guide policy-makers to mitigate negative impacts expected from future occurrences of extreme weather events.

中文翻译：

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与布隆迪近期极端降雨事件相关的气象因素的诊断

摘要 本研究旨在确定极端降雨事件的主要原因，特别是最近发生在中东非的极端降雨事件，严重影响了布隆迪西部地区，2014 年 2 月造成 77 人死亡、基础设施破坏、财产损失和土地公顷数减少。 . 为了解极端降雨发生的潜在问题及其关键驱动因素，本研究调查了 2009 年 11 月 11 日和 2014 年 2 月 9 日在布隆迪西部造成大规模损失的两个不同的极端降雨事件。描述哪一个捕获了所调查的两个极端降雨事件的可靠信息。使用欧洲中期天气预报中心 (ECMWF) 数据集对不同的天气参数进行了分析。天气研究和预测 (WRF) 模型还用于分析不同时期的不同参数，即极端降雨事件发生之前、期间和之后。发现这两个不同的降雨事件是由来自刚果盆地的潮湿空气增强的局部对流和中上层的异常条件相结合引起的。下、中上层的不稳定性主要来自位势高度和风环流的变化。当地的物理因素，特别是地形和位于非洲西部大裂谷的坦噶尼喀湖的存在增强了当地对流，引发了快速凝结，导致布隆迪西部地区出现大雨。天气状况因极端降雨事件发生的时间或季节而异。这项研究将推动未来对布隆迪极端天气事件的历史诊断和预测的研究。它还将指导政策制定者减轻未来极端天气事件发生的预期负面影响。