Mechanisms of Ocean Heat Uptake Along and Across Isopycnals
Mechanisms of Ocean Heat Uptake Along and Across Isopycnals
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DOI：
10.1175/jcli-d-21-0793.1
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发表时间：
2022-04
影响因子：
4.9
通讯作者：
L. Clement;E. McDonagh;J. Gregory;WU Q.;A. Marzocchi;J. Zika;A. J. G. NURSERa
中科院分区：
文献类型：
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作者：
L. Clement;E. McDonagh;J. Gregory;WU Q.;A. Marzocchi;J. Zika;A. J. G. NURSERa
气候系统的变暖主要在海洋中积累，建模方法的差异导致了预测海平面上升的不确定性。在这项研究中，区域温度变化的大气-海洋环流模式（HadCM 3）之间的过度（由于扰动的表面热通量）和重新分配（所产生的变化循环和扰动混合）组件。在模拟与历史强迫，我们首先比较这种过剩的再分配分区与香料和起伏分解，其中温度异常进入海洋内部无论是沿着isopycnals（香料）或跨越isopycnals（起伏，不影响温度-盐度曲线）。其次，投射到温盐空间的热量和盐度收支自然揭示了与水团产生或破坏相关的香料和升沉引起的温度变化背后的机制。过量变暖在副热带环流中以升沉增暖的形式进入海洋，而在南大洋和热带大西洋则主要投射到香料增暖上。在亚热带环流中，Ekman抽水产生了欧拉热量收支所证实的过度变暖。与此相反，等密度线混合部分驱动变暖和盐化香料，证实了预算在温盐空间，潜在的关键作用，盐度变化的海洋变暖的签名。我们的研究提出了一种方法来检测过度变暖使用香料和起伏从观察到的温度和盐度的重复配置文件计算。
Warming of the climate system accumulates mostly in the ocean and discrepancies in how this is modelled contribute to uncertainties in predicting sea level rise. In this study, regional temperature changes in an atmosphere–ocean general circulation model (HadCM3) are partitioned between excess (due to perturbed surface heat fluxes) and redistributed (arising from changing circulation and perturbations to mixing) components. In simulations with historical forcing, we firstly compare this excess–redistribution partitioning with the spice and heave decomposition, in which temperature anomalies enter the ocean interior either along isopycnals (spice) or across isopycnals (heave, without affecting the temperature-salinity curve). Secondly, heat and salinity budgets projected into thermohaline space naturally reveal the mechanisms behind temperature change by spice and heave linked with water mass generation or destruction. Excess warming enters the ocean as warming by heave in subtropical gyres whereas it mainly projects onto warming by spice in the Southern Ocean and the tropical Atlantic. In subtropical gyres, Ekman pumping generates excess warming as confirmed by Eulerian heat budgets. In contrast, isopycnal mixing partly drives warming and salinification by spice, as confirmed by budgets in thermohaline space, underlying the key role of salinity changes for the ocean warming signature. Our study suggests a method to detect excess warming using spice and heave calculated from observed repeat profiles of temperature and salinity.