Effects of Saharan Dust on the African Easterly Jet-African Easterly Wave System

北非是非洲东风急流的所在地，这是一股位于低层大气中的强劲东风。非洲东风急流经常产生被称为非洲东风波的天气系统。急流和海浪共同构成了一个复杂的系统，其对天气的影响可以延伸到美国。这种影响通常表现为热带气旋，其起源与东风波浪有关。因此，要了解北非天气与热带气旋发展之间的联系，了解影响非洲东风急流的过程是很重要的。非洲东风波系统。在这些过程中，撒哈拉沙尘暴的加热效应是最不为人所知的，但可能是最重要的。本提案的中心目标是促进对撒哈拉沙尘暴对非洲东风急流的季节内和年际变化的影响的理解。非洲东风波系统。为了实现这一目标，制定了统一的工作计划，将数值实验、观测分析和模型验证相结合。为了指导数值实验并帮助解释结果，将开发一个理论框架，揭示系统内运行的尘埃修正物理。拟议研究的科学价值包括：了解撒哈拉沙尘对非洲东部气流影响的传播途径；非洲东风波系统；为解释撒哈拉沙尘如何影响系统的时间变化提供物理基础；以及评估撒哈拉沙尘对东风海浪生命周期的重要性。拟议研究的更广泛影响包括：进一步了解撒哈拉沙尘如何影响北非的环流，这将有助于科学界？美国努力改善该地区的天气预报；改进沙尘修正系统的代表性，这将有利于今后的研究，以期增进对东大西洋热带气旋的了解和改进预报；发展理解沙尘修正环流的理论框架，可作为北非天气数值模拟和观测研究的解释工具；以及大气科学专业本科生和研究生的科学培养。

North Africa is home to the African easterly jet, a current of strong easterly winds located in the lower atmosphere. The African easterly jet often gives birth to weather systems known as African easterly waves. Together the jet and the waves form a complex system whose influence on weather can extend to the United States. That influence often manifests as tropical cyclones, whose genesis has been linked to the easterly waves. Consequently, to understand the connection between the weather over North Africa and the development of tropical cyclones, it is important to understand the processes that affect the African easterly jet‒African easterly wave system. Of those processes, the heating effects of Saharan dust storms are among the least understood, yet potentially among the most important. The central objective of this proposal is to advance understanding of the effects of Saharan dust storms on the intra-seasonal and inter-annual variability of the African easterly jet‒African easterly wave system. To achieve this objective, a unified work plan is developed that combines numerical experiments, observational analysis, and model verification. To guide the numerical experiments and to aid in the interpretation of the results, a theoretical framework will be developed that exposes the dust-modified physics operating within the system. The scientific merits of the proposed research include: understanding the pathways that communicate the effects of Saharan dust to the African easterly jet‒African easterly wave system; providing a physical basis for explaining how Saharan dust affects the temporal variability of the system; and evaluating the importance of Saharan dust to the life cycles of the easterly waves. The broader impacts of the proposed research include: additional understanding of how Saharan dust affects the circulation over North Africa, which will aid the scientific community?s efforts to improve weather forecasts for the region; improved representation of the dust-modified system, which will benefit future studies that seek to advance understanding and improve forecasting of tropical cyclones over the Eastern Atlantic Ocean; development of a theoretical framework for understanding the dust-modified circulation, which can be used as an interpretive tool for numerical modeling and observational studies of the weather over North Africa; and the scientific training of undergraduate and graduate students in the discipline of atmospheric sciences.