Mid‐latitude wind stress: the energy source for climatic shifts in the North Pacific Ocean
Mid‐latitude wind stress: the energy source for climatic shifts in the North Pacific Ocean
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中纬度风应力：北太平洋气候变化的能源
DOI：
10.1046/j.1365-2419.2000.00136.x
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发表时间：
2000
影响因子：
2.6
通讯作者：
Mendelssohn
中科院分区：
文献类型：
--
作者：
Parrish;Schwing;Mendelssohn
对北太平洋大气观测资料的分析表明，中纬度冬季地面风应力存在着广泛的十年尺度变化。在1976年冬季以后的10年中，北太平洋中部大范围的东风应力增加了一倍，冬季零风应力旋度线向南偏移了约6°。这导致向南的埃克曼输送增加，海洋上升流增加，湍流混合增加，以及表面辐散区域向南扩展。所有这些因素都导致了北太平洋副热带气流沿着侧的年代际冬季冷异常。夏季，寒冷异常向东延伸，几乎到达俄勒冈州海岸。风应力旋度梯度的增加和零旋度线向南的位移也导致了北太平洋海流总输送量的增加，主要是在该海流的赤道一侧。因此，进入加州海流的地表水在1976年后的十年中更多地来自亚热带。在旧金山弗朗西斯科外海，向南（有利的上升流）风应力和海表温度（SST）表现出至少三种不同类型的年代际偏离平均条件。与1976年的气候变化，海洋渔业生产在俄亥俄州，加州和阿拉斯加电流发生了巨大的变化，这表明这些自然环境的变化显着改变了主要的北太平洋渔业的长期产量。
Analyses of atmospheric observations in the North Pacific demonstrate extensive decadal-scale variations in the mid-latitude winter surface wind stress. In the decade after 1976 winter, eastward wind stress doubled over a broad area in the central North Pacific and the winter zero wind stress curl line was displaced about 6° southward. This resulted in increased southward Ekman transport, increased oceanic upwelling, and increased turbulent mixing as well as a southward expansion of the area of surface divergence. All these factors contributed to a decadal winter cold anomaly along the subtropical side of the North Pacific Current. In summer the cold anomaly extended eastward, almost reaching the coast of Oregon. The increased gradient in wind stress curl and southward displacement of the zero curl line also resulted in an increase in total North Pacific Current transport, primarily on the Equator side of this Current. Thus, surface water entering the California Current was of more subtropical origin in the post-1976 decade. Southward (upwelling favourable) wind stress and sea surface temperature (SST) in the area off San Francisco exhibit at least three different types of decadal departures from mean conditions. In association with the 1976 climatic shift, marine fishery production in the Oyashio, California and Alaska Currents altered dramatically, suggesting that these natural environmental variations significantly alter the long-term yields of major North Pacific fisheries.