African Monsoon Systems: Basic Dynamics and Applications to Interannual and Decadal Prediction

该项目的研究将涉及非洲季风系统的基本动态，重点是西非、大非洲之角以及从地中海穿越北非的“寒潮”的影响。 在西非，研究将侧重于惯性不稳定性在造成季风降雨从几内亚海岸突然“跳跃”到萨赫勒地区方面的作用。 在GHA中，重点是了解降雨分布与索马里急流之间的关系，索马里急流是一种低空气流，在两个不同的阶段形成，与各自次区域的季风降雨有关。 寒潮对萨赫勒地区的降雨很重要，因为它们似乎与季风季节降雨被抑制时出现的间歇期有关。 大部分工作是用一个区域气候系统模型进行的，该模型能够代表该区域的天气和气候、邻近海洋的上层以及陆地表面及其植被。 这项研究的目的是查明当今气候的有关物理机制，并将进行更多的实验，探讨人为全球变暖对非洲季风系统可能产生的影响，这项工作的更广泛影响在于有可能更好地了解非洲季风系统的动态，从而掌握预测季风变化的技能，并预测全球变暖的影响。 PI指出，本研究中考虑的地区的人口极易受到气候变异和变化的影响，原因包括粮食和水安全，健康风险和政治稳定。 这项工作还将支持一名研究生，从而有助于发展未来的科学工作队伍。

Research conducted in this project will address the basic dynamics of monsoon systems in Africa, focusing on West Africa, the Greater Horn of Africa (GHA), and the influence of "cold surges" moving across North Africa from the Mediterranean. In West Africa, the research will focus on the role of inertial instability in producing the often abrupt "jump" of the monsoon rains from the Guinea coast to the Sahel. In the GHA, the focus is on understanding the relationship between rainfall distribution and Somali jet, a low-level air current which forms in two distinct stages with are associated with the onset of monsoon rains in their respective subregions. The cold surges are important for rains in the Sahel, as they appear to be linked to the occurrence of break periods during the monsoon season when the rains are suppressed. Much of the work is carried out with a regional climate system model, which is capable of representing the weather and climate of the region, the upper layer of the adjacent oceans, and the land surface and its vegetation. The research seeks to identify the relevant physical mechanisms in present-day climate, and additional experiments will explore the possible effects of anthropogenic global warming on the African monsoon systems.The broader impacts of the work lie in the potential for a better understanding of the dynamics of the African monsoon systems to lead to skill in predicting monsoon variations, and to anticipate the effects of global warming. The PI notes that the populations of the regions considered in this study are extremely vulnerable to climate variability and change, for reasons including food and water security, health risks, and political stability. The work would also support a graduate student, thereby helping to develop the scientific workforce of the future.