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

使用 COAWST 模型揭示海面洋流梯度和海面波浪对湾流上空大气边界层物理过程的影响

• 批准号: 2307335
• 负责人: Mark Bourassa
• 金额: $ 57.52万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2307335&HistoricalAwards=false
• 关键词: Unraveling; Impacts; Ocean; Surface; Current

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.

这项研究的重点是海洋表面的洋流和波浪如何与大气一起工作，从而导致风以影响与墨西哥湾流有关的天气的方式移动热量和水分。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，这导致这些位置上的垂直运动增加。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，如果这些过程是重要的风暴前和风暴期间。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，从而有助于培养下一代具有海洋与大气相互作用方面专门知识的建模人员。所开发的建模工具也将有助于今后对这些过程进行科学调查，这项研究将增进对大气层在细微空间尺度（10至40公里）和较短时间尺度（从数小时到数天）上对与动量有关的海气耦合过程的反应的了解。该项目将侧重于墨西哥湾流区域，那里的海洋表面流的水平梯度很大，对天气的影响也很可能很大。将对耦合海洋-大气-波浪-沉积物输运（COAWST）模拟系统进行修改，以适应更多不同类型的表面阻力模型，因为先前的工作已经显示出对高分辨率（2-6公里）双向耦合海洋/波浪/大气模型中表面应力参数化的惊人的强敏感性。四个双胞胎实验将在解释双向耦合如何改变波浪和海流后，确定大气对风和波浪的敏感性。在每个孪生实验中，运行双向耦合模式以获得海洋和大气状态。然后，从耦合运行获得的海洋状态被规定为强迫大气，而不依赖于流或波。对配对运行之间以及每对成员之间的差异进行诊断。对应力参数化敏感的表面特征的验证将提供关于每个表面应力参数化的优点和缺点的见解。该项目预计将（1）确定风、水流和波浪的耦合如何改变热量、水分和水平动量的预算;（2）确定大气边界层（ABL）内以及大气边界层（ABL）和自由大气之间的垂直传输的程度通过波浪和水流对应力的影响而增强;（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加有多大贡献;以及（4）确定上述三个问题的答案如何根据天气状况而变化（例如，该奖项反映了NSF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。