Ocean-only FAFMIP: Understanding Regional Patterns of Ocean Heat Content and Dynamic Sea Level Change.
Ocean-only FAFMIP: Understanding Regional Patterns of Ocean Heat Content and Dynamic Sea Level Change.
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仅海洋 FAFMIP：了解海洋热含量和动态海平面变化的区域模式。
DOI：
10.1002/essoar.10501557.1
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Todd A
中科院分区：
文献类型：
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作者：
Todd A
人为气候变化下未来区域海平面变化存在较大的不确定性。我们的研究提出并使用了一种新颖的海洋环流模式（OGCM）实验设计，以研究海洋对表面浮力和动量通量扰动的响应，而没有大气-海洋反馈（例如，没有表面恢复或体积公式），作为通量异常强迫模型相互比较项目（FAFMIP）的一部分。在强迫相同的表面通量扰动的OGCM合奏，模拟的动态海平面（DSL）和海洋热含量（OHC）的变化表现出相当大的分歧。在北大西洋，模式之间DSL和OHC变化的差异主要是由于残余（分解和涡动）环流变化的差异，大西洋纬向翻转环流（AMOC）减弱（20-50%）。在西北太平洋，OHC的变化是类似的OGCM集合，但贡献的物理过程不同。对于南大洋，等密度混合变化和纵贯混合变化主导了OHC变化的传播。此外，大气-海洋反馈的一个组成部分是通过比较耦合，大气-海洋GCM（AOGCM）和OGCM FAFMIP实验与一致的海洋模式进行量化。我们发现，有10%以上的AOGCMs相对于OGCMs的AMOC减弱，因为由于热量再分配的北大西洋SST冷却的外热带放大了表面热通量扰动。大气-海洋反馈的这一组成部分增强了北大西洋OHC和DSL变化的模式，热带和热带外地区分别出现相对较强的增加和减少。
There is large uncertainty in the future regional sea level change under anthropogenic climate change. Our study presents and uses a novel design of ocean general circulation model (OGCM) experiments to investigate the ocean's response to surface buoyancy and momentum flux perturbations without atmosphere‐ocean feedbacks (e.g., without surface restoring or bulk formulae), as part of the Flux‐Anomaly‐Forced Model Intercomparison Project (FAFMIP). In an ensemble of OGCMs forced with identical surface flux perturbations, simulated dynamic sea level (DSL) and ocean heat content (OHC) change demonstrate considerable disagreement. In the North Atlantic, the disagreement in DSL and OHC change between models is mainly due to differences in the residual (resolved and eddy) circulation change, with a large spread in the Atlantic meridional overturning circulation (AMOC) weakening (20–50%). In the western North Pacific, OHC change is similar among the OGCM ensemble, but the contributing physical processes differ. For the Southern Ocean, isopycnal and diapycnal mixing change dominate the spread in OHC change. In addition, a component of the atmosphere‐ocean feedbacks are quantified by comparing coupled, atmosphere‐ocean GCM (AOGCM) and OGCM FAFMIP experiments with consistent ocean models. We find that there is 10% more AMOC weakening in AOGCMs relative to OGCMs, since the extratropical North Atlantic SST cooling due to heat redistribution amplifies the surface heat flux perturbation. This component of the atmosphere‐ocean feedbacks enhances the pattern of North Atlantic OHC and DSL change, with relatively stronger increases and decreases in the tropics and extratropics, respectively.