A Simple Model of the Response of the Atlantic to the North Atlantic Oscillation
A Simple Model of the Response of the Atlantic to the North Atlantic Oscillation
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DOI：
10.1175/jcli-d-13-00330.1
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发表时间：
2014-05
影响因子：
4.9
通讯作者：
Xiaoming Zhai;H. Johnson;D. Marshall
中科院分区：
文献类型：
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作者：
Xiaoming Zhai;H. Johnson;D. Marshall
在减重模型的框架内，对理想化大西洋对与北大西洋涛动 (NAO) 相关的风和温盐强迫的响应进行了分析和数值研究。研究发现，与 NAO 相关的风力驱动了一种与时间相关的“泄漏”环流，该环流整合了盆地范围内的随机风埃克曼泵送，并沿西部边界启动低频变化。随后，这与高纬度温盐强迫引起的随机变化一起通过边界波和罗斯贝波传递到大西洋的其余部分。在低频下，由于 NAO 风强迫和温盐强迫彼此相反，导致流域范围内的海洋热含量发生变化。该模型进一步表明，最近报道的1950-70年和1980-2000年间大西洋副热带和副极地环流经向翻转环流的相反变化可能是由NAO风和温盐强迫之间的相互作用引起的一般特征。
The response of an idealized Atlantic Ocean to wind and thermohaline forcing associated with the North Atlantic Oscillation (NAO) is investigated both analytically and numerically in the framework of a reducedgravity model. The NAO-related wind forcing is found to drive a time-dependent ‘‘leaky’’ gyre circulation that integrates basinwide stochastic wind Ekman pumping and initiates low-frequency variability along the western boundary. Thisissubsequentlycommunicated, togetherwith the stochasticvariability induced bythermohaline forcing at high latitudes, to the remainder of the Atlantic via boundary and Rossby waves. At low frequencies, the basinwide ocean heat content changes owing to NAO wind forcing and thermohaline forcing are found to oppose each other. The model further suggests that the recently reported opposing changes of the meridional overturning circulation in the Atlantic subtropical and subpolar gyres between 1950‐70 and 1980‐2000 may be a generic feature caused by interplay between the NAO wind and thermohaline forcing.