High‐Frequency Submesoscale Motions Enhance the Upward Vertical Heat Transport in the Global Ocean
High‐Frequency Submesoscale Motions Enhance the Upward Vertical Heat Transport in the Global Ocean
复制标题
DOI：
10.1029/2020jc016544
复制
发表时间：
2020-09
期刊：
影响因子：
--
通讯作者：
Z. Su;H. Torres;P. Klein;A. Thompson;L. Siegelman;Jinbo Wang;D. Menemenlis;C. Hill
中科院分区：
文献类型：
--
作者：
Z. Su;H. Torres;P. Klein;A. Thompson;L. Siegelman;Jinbo Wang;D. Menemenlis;C. Hill
海洋热吸收率取决于海洋表面和海洋内部之间的热输送机制。最近的一项研究发现，尺度小于50公里（亚中尺度）和频率小于一天（⁻¹）的运动驱动的垂直热输送呈上升趋势。这种输送与全球热输送的其他主要组成部分竞争，即由大尺度风驱动的垂直环流和小尺度垂直扩散解释的向下热输送，以及与中尺度涡旋（50 - 300公里）相关的向上热输送。小空间尺度（< 50公里）和频率大于一天的运动（包括内部重力波）的贡献从未被明确估计过。本研究探讨了这种高频（次日）亚中尺度对全球热输送的贡献。基于对高分辨率海洋模型的分析，这项研究的主要结果是，包括这种高频贡献在内，全球海洋冬季由于亚中尺度而向上的热输送惊人地增加了一倍。这种贡献通常涉及200 - 500米以下的深度，冬季40米深度的热通量可高达500 W/m²，在全球海洋上综合起来，这导致了约7 PW的显著向上热输送。因此，这种未被气候模式解决的亚中尺度热输送影响了全球海洋的热吸收。这些结果所涉及的机制仍然需要了解，这应该是未来工作的范围。
The rate of ocean heat uptake depends on the mechanisms that transport heat between the surface and the ocean interior. A recent study found that the vertical heat transport driven by motions with scales smaller than 50 km (submesoscales) and frequencies smaller than one day⁻¹ is upward. This transport competes with the other major components of the global heat transport, namely the downward heat transport explained by the large‐scale wind‐driven vertical circulation and vertical diffusion at small scales, and the upward heat transport associated with mesoscale eddies (50‐300 km size). The contribution from motions with small spatial scales (< 50 km) and frequencies larger than one day⁻¹, including internal gravity waves, has never been explicitly estimated. This study investigates this high‐frequency (sub‐daily) submesoscale contribution to the global heat transport. The major result of this study, based on the analysis of a high‐resolution ocean model, is that including this high‐frequency contribution surprisingly doubles the upward heat transport due to submesoscales in winter in the global ocean. This contribution typically concerns depths down to 200‐500 m and can have a magnitude of up to 500 W/m² in terms of heat fluxes at 40 m depth during winter, which causes a significant upward heat transport of ~7 PW when integrated over the global ocean. Thus, such submesoscale heat transport, which is not resolved by climate models, impacts the heat uptake in the global ocean. The mechanisms involved in these results still need to be understood, which should be the scope of future work.