Unraveling the Impacts of Ocean Surface Current Gradients and Ocean Surface Waves on Atmospheric Boundary Layer Physical Processes over the Gulf Stream Using COAWST Model

这项研究的重点是海洋表面流和海浪如何与大气合作，以影响与墨西哥湾流有关的天气的方式产生风，移动热量和水分。海流和波浪的位置差异导致大气感受到的表面摩擦力的差异，从而导致这些位置上垂直运动的区域增加。这种运动有助于将热量和水分输送到影响天气的高度。这项研究调查了这些过程在风暴前和风暴期间是否重要。如果这些过程被发现是重要的，所获得的知识将改善天气预报。这项研究的很大一部分将由一名研究生进行；因此，有助于培养下一代具有海洋和大气相互作用专业知识的模型师。所开发的模拟工具也将有助于今后对这些过程的科学调查。这项研究将在精细空间尺度(10至40公里)和较短时间尺度(从几小时到几天)上增进对与动量有关的海-气耦合过程的大气响应的理解。该项目将把重点放在墨西哥湾流区域，那里的海洋表面流水平梯度大，对天气的影响更大。海洋-大气-波浪-沉积物耦合输送(COAWST)模式系统将被修改为更多不同类型的表面阻力模式，因为以前的工作对高分辨率(2-6公里)双向海洋/波浪/大气模式中的表面应力参数化表现出惊人的敏感性。在考虑了双向耦合如何改变海浪和海流之后，四个孪生实验将确定大气对风和浪的敏感性。在每一个孪生实验中，运行双向耦合模型以获得海洋和大气的状态。然后，从耦合运行中获得的海洋状态被规定为强迫大气，而不依赖于海流或波浪。诊断出夫妇之间以及每对成员之间的差异。验证对应力参数化敏感的表面特征将有助于深入了解每种表面应力参数化的优缺点。该项目预计将：(1)确定风、流和海浪的耦合如何改变热量、水汽和水平动量的收支；(2)确定波浪和海流对应力的影响在多大程度上加强了大气边界层(ABL)内以及ABL和自由大气之间的垂直输送；(3)确定耦合模式中增强的垂直运动和输送对对流和风暴强度的增强有多大贡献；以及(4)根据天气状况(例如，边界层稳定性、风速和与大气锋面的相互作用)确定上述三个问题的答案如何变化。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This research focuses on how ocean surface currents and waves work with the atmosphere to cause winds that move heat and moisture in a manner that influences weather related to the Gulf Stream. Location-to-location differences in currents and waves cause differences in the surface friction felt by the atmosphere, which results in areas of increased vertical motion over these locations. That motion helps transport heat and moisture to heights that influence weather. This study investigates if these processes are important before storms and during storms. If these processes are found to be important, the knowledge obtained will improve weather forecasts. A significant amount of this research will be carried out by a graduate student; thus, contributing to the training of the next generation of modelers with expertise in interaction between the ocean and atmosphere. Modeling tools developed will also help future science investigations of these processes.This research will improve understanding of the atmospheric responses to momentum-related air-sea coupling processes on fine spatial scales (10 to 40 km) and at shorter timescales (from hours to several days). This project will focus on the Gulf Stream region where horizontal gradient of ocean surface current is large and where impacts on weather are more likely to be large. The Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system will be modified to more different types of models of surface drag because prior work has shown surprisingly strong sensitivity to the surface stress parameterization in high-resolution (2-6 km) two-way coupled ocean/wave/atmosphere models. Four twin experiments will determine the atmospheric sensitivity to winds and waves after accounting for how two-way coupling modifies the waves and currents. In each twin experiment, the two-way coupled model is run to obtain the ocean and atmosphere states. Then the ocean state obtained from the coupled run is prescribed to force the atmosphere without the dependency on currents or waves. Differences between couple runs and between members of each pair are diagnosed. Validation of surface characteristics sensitive to stress parameterization will provide insights about the strengths and weakness of each surface stress parameterization. This project is anticipated to (1) determine how coupling of winds, currents, and waves modifies budgets of heat, moisture, and horizontal momentum; (2) determine the extent to which vertical transport within the atmospheric boundary-layer (ABL) and between the ABL and free atmosphere is enhanced by wave and current influences on stress; (3) determine how much the enhanced vertical motion and transport in the coupled model contributes to increased convection and storm intensity; and (4) determine how the answers to the above three questions change depending on weather regimes (e.g., boundary layer stability, wind speed, and interaction with atmospheric fronts).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.