An Anatomy of the Cooling of the North Atlantic Ocean in the 1960s and 1970s
An Anatomy of the Cooling of the North Atlantic Ocean in the 1960s and 1970s
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DOI：
10.1175/jcli-d-14-00301.1
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发表时间：
2014-11-01
影响因子：
4.9
通讯作者：
Sutton, Rowan T.
中科院分区：
文献类型：
--
作者：
Hodson, Daniel L. R.;Robson, Jon I.;Sutton, Rowan T.
在1960年代和1970年代初，北大西洋的海面温度迅速冷却。尽管提出了各种机制，但对这一事件的原因仍有相当大的不确定性。在这项观察研究中，证明了冷却是在几个不同的阶段进行的。冷异常最初出现在20世纪60年代中期的北欧海和墨西哥湾流延伸区，然后蔓延到大部分副极地环流。随后，冷异常扩散到热带北大西洋，然后在20世纪70年代末撤退到副极地环流。有强有力的证据表明，与大西洋ITCZ南移有关的大气环流变化在这一事件中发挥了重要作用，特别是在1972-76年期间。冷却事件的理论必须解释其独特的时空演化。作者的分析表明，最可能的驱动因素是：1）20世纪60年代末的“大盐度异常”; 2）北大西洋副极地的早期变暖，这可能导致大西洋纬向翻转环流的减缓; 3）人为二氧化硫排放量的增加。确定这些因素的相对重要性是今后工作的一个关键领域。
In the 1960s and early 1970s, sea surface temperatures in the North Atlantic Ocean cooled rapidly. There is still considerable uncertainty about the causes of this event, although various mechanisms have been proposed. In this observational study, it is demonstrated that the cooling proceeded in several distinct stages. Cool anomalies initially appeared in the mid-1960s in the Nordic Seas and Gulf Stream extension, before spreading to cover most of the subpolar gyre. Subsequently, cool anomalies spread into the tropical North Atlantic before retreating, in the late 1970s, back to the subpolar gyre. There is strong evidence that changes in atmospheric circulation, linked to a southward shift of the Atlantic ITCZ, played an important role in the event, particularly in the period 1972-76. Theories for the cooling event must account for its distinctive space-time evolution. The authors' analysis suggests that the most likely drivers were 1) the "Great Salinity Anomaly" of the late 1960s; 2) an earlier warming of the subpolar North Atlantic, which may have led to a slowdown in the Atlantic meridional overturning circulation; and 3) an increase in anthropogenic sulfur dioxide emissions. Determining the relative importance of these factors is a key area for future work.