HBCU: Excellence in Research: Analysis and Modeling of the Ocean Spray Effects on Tropical Cyclone Dynamics

有充分的证据表明，近几十年来，飓风路径预报有了很大的改进，而飓风强度变化的预报却滞后了。飓风强度对风切变和气旋内部组织等多种因素都很敏感。研究飓风行为的主要不确定性之一是海洋喷雾对系统的作用。海洋喷雾影响空气-海洋的动量、热量和水分交换。在这些条件下的直接观测很少而且非常困难，因此对海洋喷雾的大部分理解都来自较平静的条件或数值模型。在这个项目中，PI计划从基本物理守恒定律的角度来解决这个问题，逐步建立一个更详细的海浪数学模型。这项工作的最终社会影响将是通过改进数值天气模型，从而更好地预测飓风及其影响。该项目还将代表一所历史悠久的黑人学院和大学的研究和教育的加强。该项目计划建立一个数学上严谨、物理上合理的海洋大气边界层模型，该模型包含蒸发的海沫，并对该模型进行数值和渐近分析，以有效地参数化海沫对热带气旋动力学和结构的影响。起点将是一套基本的守恒定律，这些定律将被应用于系统地逐步发展更全面的模型，以便清楚地识别新增加的物理因素的影响。在建立模型的第一个目标下，PI计划推导宏观尺度，多流体输运方程，制定多相湍流模型，并分析液滴种群动力学。模型的渐近分析和数值分析将通过对模型进行正则渐近展开、奇异渐近展开和数值分析来进行。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。

It is well-documented that hurricane track forecasts have improved substantially over the recent decades, while forecasts of hurricane intensity change have lagged. Hurricane intensity is sensitive to a variety of factors, such as wind shear and the internal organization of the cyclone. One of the main uncertainties in research on hurricane behavior is the role of ocean spray on the system. Ocean spray affects the air-sea exchange of momentum, heat, and moisture. Direct observations in these conditions are rare and very difficult, so most of the understanding about ocean spray is from calmer conditions or numerical models. In this project, the PI plans to come at the problem from the perspective of fundamental physical conservation laws, progressively building a more elaborate mathematical model of sea spray. The eventual societal impact of this work would be through improvements in numerical weather models, which would translate to better forecasts of hurricanes and their impacts. The project would also represent the enhancement of research and education at a Historically Black College and University.The PI plans to develop a mathematically rigorous and physically sound model of a marine atmospheric boundary layer laden with evaporating sea spray and perform numerical and asymptotic analyses of the model to create an efficient parameterization of a sea spray effect on tropical cyclone dynamics and structure. The starting point will be a set of fundamental conservation laws which will be applied to systematically develop progressively more comprehensive models in such a way that the influence of newly added physical factors is clearly identifiable. Under the first objective of developing the model, the PI plans the derivation of macro-scale, multi-fluid transport equations, formulation of the multi-phase turbulence model, and analysis of the droplet population dynamics. The asymptotic and numerical analysis of the model would be conducted by performing regular asymptotic expansions, singular asymptotic expansions, and numerical analysis of the model.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.