Observed Basin-Scale Response of the North Atlantic Meridional Overturning Circulation to Wind Stress Forcing
Observed Basin-Scale Response of the North Atlantic Meridional Overturning Circulation to Wind Stress Forcing
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DOI：
10.1175/jcli-d-16-0664.1
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发表时间：
2017-03-01
影响因子：
4.9
通讯作者：
Lankhorst, Matthias
中科院分区：
文献类型：
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作者：
Elipot, Shane;Frajka-Williams, Eleanor;Lankhorst, Matthias
从观测角度研究了北大西洋经向翻转环流（MOC）对风应力强迫的响应，使用了四个在1000米以下及相对于1000米的翻转输送时间序列，重叠3.6年。这些时间序列来自位于北大西洋西部边界的四个系泊阵列：RAPID西大西洋变率实验（WAVE）阵列（北纬42.5度）、伍兹霍尔海洋研究所W线阵列（北纬39度）、RAPID - MOC/MOCHA（北纬26.5度）以及经向翻转变率实验（MOVE）阵列（北纬16度）。通过对输送量和风应力之间解析互相关的模态分解，在本研究可用的时间尺度上，表明盆地尺度的风应力在四个纬度上对MOC有显著的一致性驱动作用。协方差的主导模态被解释为海洋对风应力强迫的快速正压调整，最终形成以热带和副热带环流为中心的两个反向旋转的埃克曼翻转环流。协方差的第二种模态似乎与北大西洋涛动相关的风应力和风应力旋度模式有关，产生异常的水平环流，这些环流可能与地形相互作用形成翻转环流。
The response of the North Atlantic meridional overturning circulation (MOC) to wind stress forcing is investigated from an observational standpoint, using four time series of overturning transports below and relative to 1000 m, overlapping by 3.6 yr. These time series are derived from four mooring arrays located on the western boundary of the North Atlantic: the RAPID Western Atlantic Variability Experiment (WAVE) array (42.5 degrees N), the Woods Hole Oceanographic Institution Line W array (39 degrees N), RAPID-MOC/MOCHA (26.5 degrees N), and the Meridional Overturning Variability Experiment (MOVE) array (16 degrees N). Using modal decompositions of the analytic cross-correlation between transports and wind stress, the basin-scale wind stress is shown to significantly drive the MOC coherently at four latitudes, on the time scales available for this study. The dominant mode of covariance is interpreted as rapid barotropic oceanic adjustments to wind stress forcing, eventually forming two counterrotating Ekman overturning cells centered on the tropics and subtropical gyre. A second mode of covariance appears related to patterns of wind stress and wind stress curl associated with the North Atlantic Oscillation, spinning anomalous horizontal circulations that likely interact with topography to form overturning cells.