Understanding High-Impact Rainfall Events over the West African Sahel: Resolving the Role of Environmental Conditions on Storm Processes

虽然洪水是一个复杂的过程，涉及气象系统和地面条件，但大多数高影响事件的特点是高降雨量。这项研究的重点是了解在西非萨赫勒地区带来高降雨量的风暴系统，这是一个相对偏远的地区，由于频繁发生强降雨和相对较低的适应能力，已知特别容易受到洪水的影响。总体目标是通过调查环境条件如何促进这种风暴的发展，提高我们对西非萨赫勒地区极端降雨产生系统发展的物理理解。考虑到高影响降雨事件对西非人生计的影响，以及这些系统在西非萨赫勒地区大西洋飓风中的已知作用，从这项研究中获得的知识不仅对改善西非萨赫勒地区高影响降雨事件的预测，而且对我们自己国家利益的天气预报都很有价值。该项目还通过参与和培训一名博士后研究员和一名研究生，以及通过K-12外展计划，为下一代大气科学家的教育做出贡献。该项目的具体目标是：(1)了解产生高影响降雨量的降水系统的特征；(2)确定有利于这些降雨事件发展的环境条件。这些目标将通过利用高分辨率卫星衍生的降雨产品、最先进的大气再分析数据以及允许对流的区域气候模型来实现。卫星导出的降雨量估计和地面观测将用于识别和描述该地区的高影响降雨事件，这些将与地面实况交叉参考，以识别与报告的洪水相关的事件。大气再分析数据和允许对流的建模将用于确定与强风暴相关的环境条件，并开发和测试关于它们如何相关的假设，以加深我们对与高影响降雨事件发展相关的物理过程的理解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

While flooding is a complex process involving both meteorological systems and surface conditions, most high-impact events are characterized by high rainfall totals. This study focuses on understanding storm systems that deliver high rainfall amounts over the West African Sahel, a relatively remote region known to be particularly vulnerable to flooding due to the frequent occurrence of intense rainfall and relatively low adaptive capacity. The overarching goal is to advance our physical understanding of the development of extreme rainfall-producing systems over the West African Sahel by investigating how environmental conditions contribute the development of such storms. Given the consequences of high-impact rainfall events for the livelihoods of West Africans, as well as the known role of these systems over the West African Sahel in Atlantic hurricanes, the knowledge gained from this study will be valuable for improving not only the prediction of high-impact rainfall events over the West African Sahel but also the weather forecast for our own national interests. The project also contributes to the education of the next generation of atmospheric scientists through involving and training a post-doctoral researcher and a graduate student as well as through a K-12 outreach program. The specific objectives of this project are: (1) to understand the characteristics of precipitating systems that deliver high-impact rainfall amounts; and (2) to determine the set of environmental conditions that favor the development of these rainfall events. These objectives will be addressed by utilizing high-resolution satellite-derived rainfall products, state-of-the-art atmospheric reanalysis data, along with convection-permitting regional climate modeling. Satellite-derived rainfall estimates and ground-based observations will be used to identify and characterize high-impact rainfall events over the region, and these will be cross-referenced with ground-truth to identify events associated with reported flooding. Atmospheric reanalysis data and convection-permitting modeling will be used to identify the environmental conditions associated with intense storms, and to develop and test hypotheses regarding how they are related to deepen our understanding of the physical processes associated with the development of high-impact rainfall events.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.