Observational Assessment of Nonlocal Heat Flux Feedback in the North Atlantic by GEFA
Observational Assessment of Nonlocal Heat Flux Feedback in the North Atlantic by GEFA
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DOI：
10.1175/jamc-d-11-0257.1
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发表时间：
2013-03
影响因子：
3
通讯作者：
Na Wen;Zhengyu Liu;Qinyu Liu
中科院分区：
文献类型：
--
作者：
Na Wen;Zhengyu Liu;Qinyu Liu
摘要 以往的研究大多证实了中纬度地区局部热通量负反馈（地表热通量对海温异常的响应）。然而，是否可以观察到非局部热通量反馈尚不确定。本文采用广义平衡反馈评估（GEFA）方法，利用 NCEP-NCAR 再分析数据来研究北大西洋全表面湍流热通量对海表温度的响应。结果不仅证实了占主导地位的局地负反馈，而且表明了湾流延伸（GSE）海温对副极地下游热通量的强劲非局地正反馈。这种非本地反馈具有很强的季节性，冬季和夏季的响应幅度不同。进一步研究表明，非局地效应是由下游地面风对GSE海温异常的调整引发的。
AbstractMost previous studies have proven the local negative heat flux feedback (the surface heat flux response to SST anomalies) in the midlatitude areas. However, it is uncertain whether a nonlocal heat flux feedback can be observed. In this paper, the generalized equilibrium feedback assessment (GEFA) method is employed to examine the full surface turbulent heat flux response to SST in the North Atlantic Ocean using NCEP–NCAR reanalysis data. The results not only confirm the dominant local negative feedback, but also indicate a robust nonlocal positive feedback of the Gulf Stream Extension (GSE) SST to the downstream heat flux in the subpolar region. This nonlocal feedback presents a strong seasonality, with response magnitudes of in winter and in summer. Further study indicates that the nonlocal effect is initiated by the adjustments of the downstream surface wind to the GSE SST anomalies.