Drivers of Local Ocean Heat Content Variability in ECCOv4
Drivers of Local Ocean Heat Content Variability in ECCOv4
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DOI：
10.1175/jcli-d-20-0058.1
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发表时间：
2020-02
影响因子：
4.9
通讯作者：
Jan‐Erik Tesdal;R. Abernathey
中科院分区：
文献类型：
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作者：
Jan‐Erik Tesdal;R. Abernathey
上层海洋热含量的变化是理解全球气候变异性的关键因素。利用20年物理上一致的海洋状态估计(ECCOv4r3；1992-2015)中的温度异常预算，我们描述了不同深度水平和不同时间和空间分辨率的大气强迫和海洋传输机制之间的平衡。平流在热带地区占主导地位，而强迫在高纬度和副热带部分地区最相关，但当积分到更深处并考虑更长的时间尺度时，主导过程的平衡发生了变化。虽然强迫随分辨率增大而增加，但总体上，强迫与平流之间的热量平衡对空间尺度不敏感。通过将非监督分类与热量收支方面的时间可变性衡量相结合，以确定具有类似基本机制的连贯动力制度，从而实现了关于全球海洋热含量可变性的新视角，这与先前的研究一致。海洋的绝大多数都包括强迫和平流的重大贡献。然而，发现了与强流重合的平流驱动区，如西部边界流、南极绕极流和热带，而强迫驱动区则由较浅的冬季混合层和弱速度场界定。这种对综合动力体制的确定和海洋热收支分析对精确分辨率的敏感性(对于不同的深度层位和不同的时间和空间分辨率)，应为今后研究特定海洋区域的海洋热含量变异性提供一个有用的方向。
Variation in upper-ocean heat content is a critical factor in understanding global climate variability. Using temperature anomaly budgets in a two-decade-long physically consistent ocean state estimate (ECCOv4r3; 1992–2015), we describe the balance between atmospheric forcing and ocean transport mechanisms for different depth horizons and at varying temporal and spatial resolutions. Advection dominates in the tropics, while forcing is most relevant at higher latitudes and in parts of the subtropics, but the balance of dominant processes changes when integrating over greater depths and considering longer time scales. While forcing is shown to increase with coarser resolution, overall the heat budget balance between it and advection is remarkably insensitive to spatial scale. A novel perspective on global ocean heat content variability was made possible by combining unsupervised classification with a measure of temporal variability in heat budget terms to identify coherent dynamical regimes with similar underlying mechanisms, which are consistent with prior research. The vast majority of the ocean includes significant contributions by both forcing and advection. However advection-driven regions were identified that coincide with strong currents, such as western boundary currents, the Antarctic Circumpolar Current, and the tropics, while forcing-driven regions were defined by shallower wintertime mixed layers and weak velocity fields. This identification of comprehensive dynamical regimes and the sensitivity of the ocean heat budget analysis to exact resolution (for different depth horizons and at varying temporal and spatial resolutions) should provide a useful orientation for future studies of ocean heat content variability in specific ocean regions.