An observations and model‐based analysis of meridional transports in the South Atlantic
An observations and model‐based analysis of meridional transports in the South Atlantic
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DOI：
10.1002/2016jc011693
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发表时间：
2016-08
影响因子：
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通讯作者：
Sudip Majumder;C. Schmid;G. Halliwell
中科院分区：
文献类型：
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作者：
Sudip Majumder;C. Schmid;G. Halliwell
根据Argo观测数据和海面高度（以下称为Argo和SSH）构建的三维速度场用于估算2000-2014年南大西洋20°S、25°S、30°S和35°S的经向翻转体积传输和经向热传输（MHT）。观测得到的经向翻转环流（MOC）和MHT上分支的体积输送与之前的观测结果一致，但在某些纬度高于根据三个数据同化海洋模型得出的估计值。观测结果和模型都显示出所有纬度的 MOC 和 MHT 强度之间存在很强的相关性。在观测中，MOC 强度每变化 1 Sv，MHT 的相应变化从 25°S、30°S 和 35°S 的 0.046 PW 增加到 20°S 的 0.056 PW。将边界和内部的 35°S 处基于模型的输运与来自 Argo 和 SSH 的输运进行比较，表明它们之间在剖面三个部分的贡献方面存在显着差异。此外，不同模型之间的贡献也有很大差异。对模型和观测中 MOC 季节性的分析表明，模型中的 MOC 异常在所有纬度上大多表现出较强的年周期，而来自 Argo 和 SSH 的 MOC 异常在三个纬度（35°S、30°S 和较小程度的 25°S）表现出年周期，在 20°S 处呈现半年周期。
A three-dimensional velocity field constructed from Argo observations and sea surface heights (called Argo and SSH, hereinafter) is used to estimate meridional overturning volume transport and meridional heat transport (MHT) across 20°S, 25°S, 30°S, and 35°S for the years 2000–2014 in the South Atlantic. Volume transport in the upper branch of Meridional Overturning Circulation (MOC) and MHT from the observations are consistent with the previous observations, but are higher than the estimates derived from three data assimilative ocean models, at some of the latitudes. Both the observations and models show strong correlations between the strength of MOC and MHT at all the latitudes. The corresponding change in MHT for 1 Sv change of MOC strength, in the observations, increases from 0.046 PW in 25°S, 30°S, and 35°S to 0.056 PW across 20°S. A comparison of model-based transports at 35°S at the boundaries and in the interior with those from Argo and SSH shows significant differences between them with respect to the contributions in the three segments of the section. In addition, the contributions also vary greatly between the different models. An analysis of the seasonality of MOC in the models and in the observations reveals that MOC anomalies in the models mostly show strong annual cycles at all the latitudes, whereas those derived from Argo and SSH exhibit annual cycles at three latitudes (35°S, 30°S, and to a lesser extent at 25°S) and a semiannual cycle at 20°S.