Atlantic meridional heat transports in two ocean reanalyses evaluated against the RAPID array
Atlantic meridional heat transports in two ocean reanalyses evaluated against the RAPID array
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DOI：
10.1029/2012gl054581
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发表时间：
2013-01-28
影响因子：
5.2
通讯作者：
Zuo, Hao
中科院分区：
文献类型：
--
作者：
Haines, Keith;Stepanov, Vladimir N.;Zuo, Hao
两个版本的NEMO 1/4度全球海洋模式中的大西洋经向翻转环流与北纬26度的快速输送序列进行了比较，两个模式都很好地再现了平均MOC强度，尽管佛罗里达海峡的气流不同，因为墨西哥湾流的路径在这个分辨率下没有强烈的约束。然而，这两个模型的平均经向热传输为1.07PW，远低于2004年4月至2007年10月快速观测的1.35PW。热量输送的差异很大程度上是由于夏季穿越中大洋(巴哈马-非洲)的输送较少，这是因为在水最温暖的100米顶部有更强的向南地转流。温跃层的季节性变化增加了整个盆地的温差，驱动了更强的地转切变，但在快速速度数据的顶部100m处，这种影响要弱得多。这一效应使MOC和热传输分别降低了1.1Sv和0.1PW。其余的差异来自使用ERAInterim风而不是QuikSCAT的较低Ekman输送，QuikSCAT是一种较小的纬向变化的“涡流”热量输送成分，根据观测中重复的XBT截面估计，以及模式中向南的穿透气流。描述了模式MOC和快速观测在深度结构上的其他差异，但对热量传输的影响要小得多。引用：Haines，K.，V.N.Stepanov，M.Valdieso，和H.Zuo(2013)，在两个海洋再分析中的大西洋经向热输送，根据快速阵列地球物理进行评估。网址：10.1029/2012GL054581。
The Atlantic meridional overturning circulation in two versions of the NEMO 1/4 degrees global ocean model has been compared with the RAPID transport array at 26 degrees N. Both model versions reproduce the mean MOC strength well although the Florida Straits flows differ because the pathway of the Gulf Stream is not strongly constrained at this resolution. Both models however have a mean meridional heat transport of 1.07PW, much lower than the 1.35PW from RAPID observations in April 2004-October 2007. Much of the heat transport discrepancy is due to lower transports in summer across the MidOcean (Bahamas-Africa) section, due to stronger southward geostrophic flows in the top 100 m where the water is warmest. Seasonal thermocline changes increase temperature differences across the basin driving stronger geostrophic shear, but this effect is much weaker in the top 100 m of the RAPID velocity data. The effect accounts for a reduction of 1.1Sv in MOC and 0.1PW in heat transports. The rest of the discrepancy comes from lower Ekman transports from using ERAInterim winds instead of QuikSCAT, a smaller zonally varying "Eddy" heat transport component, estimated from repeat XBT sections in the observations, and the southward throughflow in the model. Other differences in depth structure of the model MOC and RAPID observations are described but have much less impact on heat transports. Citation: Haines, K., V. N. Stepanov, M. Valdivieso, and H. Zuo (2013), Atlantic meridional heat transports in two ocean reanalyses evaluated against the RAPID array, Geophys. Res. Lett., 40, 343-348, doi:10.1029/2012GL054581.