NSFGEO-NERC: Scattering of ocean surface gravity waves by submesoscale turbulence

这是一个由国家科学基金会地球科学理事会(NSF/GEO)和英国国家环境研究理事会(UKRI/NERC)通过NSF/GEO-NERC牵头机构协议共同资助的项目。该协定允许美国和英国提交一个单一的联合提案，并由该机构进行同行审查，该机构的调查员在预算中所占比例最大。在成功地联合确定一项裁决后，每个机构将为预算的比例以及与其自己的调查员和工作部分有关的调查员提供资金。次中尺度流对海面重力波的随机散射、折射和聚焦导致波场的空间调制或斑块。在这些区域内，在10到100公里的水平尺度和几个小时到一天的时间尺度上，显著的波高可能相差30%。因此，地块对表面重力波的建模和预测及其对海洋环流的影响构成了重大挑战。补丁影响海浪破碎率和与气候有关的海气相互作用，如气体交换率、气溶胶产生和海洋的风应力耦合。斑块可能是海况偏差的重要贡献者，这些偏差使海流的测高推断复杂化。该项目将包括未分辨海流的统计效应，从而消除与延迟涌浪到达有关的误差，从而有助于改进业务地面重力波模型的性能。这将改善对海浪活动的预测，用于海军、商业和娱乐应用。本项目将应用动力学理论和一种新版本的广义拉格朗日平均理论，来论证次中尺度流对波的影响以及波对次中尺度流的相互作用。将发展次中尺度湍流对地表重力波散射的新统计模式。这些模型将反过来被用来解释斑块可变性的主要特征，包括最近发现的有效波高功率谱与亚中尺度动能谱之间的关系，并开发将被纳入WaveWatch III的亚中尺度湍流对地表重力波散射的参数化。显著波高的空间和时间波动反映在表面重力波场的其他属性中，包括斯托克斯速度，因此控制表面重力波强迫洋流的波浪平均涡旋和斯托克斯-科里奥利力。将对波浪和平均流之间的相互作用在斑块时间和空间尺度上很强的假设进行调查，并将开发新的建模工具并根据这些尺度量身定做。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 is a project that is jointly funded by the National Science Foundation’s Directorate of Geosciences (NSF/GEO) and the National Environment Research Council (UKRI/NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award, each Agency funds the proportion of the budget and the investigators associated with its own investigators and component of the work. Random scattering, refraction and focusing of ocean surface gravity waves by submesoscale currents results in spatial modulation — or patches — in the wave field. Within these patches the significant wave height may vary by as much as 30% on horizontal scales of 10 to 100 km and time scales of a few hours to a day. As a result, patches pose a major challenge for the modelling and prediction of surface gravity waves and of their impact on the ocean circulation. Patches affect the wave-breaking rate, and climate-relevant air-sea interaction such as gas exchange rates, aerosol production and wind-stress coupling to the ocean. Patches are likely important contributors to sea-state bias errors that complicate altimetric inference of currents. The project will contribute to improving the performance of operational surface gravity wave models by including the statistical effects of unresolved currents, consequently removing errors related to delayed swell arrival. This will improve predictions of wave activity with naval, commercial, and recreational applications. This project will apply kinetic theory, and a new version of generalized Lagrangian mean theory, to demonstrate the effect of submesoscale currents on waves and the reciprocal effect of waves on submesoscale currents. New statistical models of the scattering of surface gravity waves by submesoscale turbulence will be developed. These models will in turn be used to explain the main features of patch variability, including a recently discovered relation between the power spectrum of significant wave height and the submesoscale kinetic energy spectrum, and to develop a parametrization of surface gravity wave scattering by submesoscale turbulence that will be incorporated into WAVEWATCH III. Spatial and temporal fluctuations in significant wave height are reflected in other properties of the surface gravity wave field including the Stokes velocity, and hence the wave-averaged vortex and Stokes-Coriolis forces which control the forcing of currents by surface gravity waves. The hypothesis that the interaction between waves and mean flows is strong on patch time and space scales will be investigated and new modeling tools will be developed and tailored to these scales.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.