Drivers of exceptionally cold North Atlantic Ocean temperatures and their link to the 2015 European heat wave
Drivers of exceptionally cold North Atlantic Ocean temperatures and their link to the 2015 European heat wave
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DOI：
10.1088/1748-9326/11/7/074004
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发表时间：
2016-07-01
影响因子：
6.7
通讯作者：
Hirschi, Joel J-M
中科院分区：
文献类型：
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作者：
Duchez, Aurelie;Frajka-Williams, Eleanor;Hirschi, Joel J-M
北大西洋和欧洲在2015年经历了两次极端气候事件：异常寒冷的海洋表面温度和65年来排名前十的夏季热浪。在这里，我们展示了东北大西洋中高纬度大部分地区的寒冷海洋温度是现代记录中最极端的。此外，通过考虑表面热损失、海洋热含量和风驱动的上升流，我们首次解释了这种冷海异常的成因。我们发现，这主要是由于前两个冬季大气环流变化导致的极端海洋热损失，以及冷海洋水团的重新出现。此外，我们还发现，在20世纪80年代以来最极端的欧洲热浪之前，也存在类似的大西洋冷异常，这表明它是这些事件发展的共同因素。对于2015年的具体情况，我们发现海洋异常与急流的静止位置有关，急流有利于在热浪期间在中欧上空发展高表面温度。我们的研究呼吁紧急评估海洋驱动因素对欧洲夏季主要极端气温的影响，以便对这些高社会影响事件提供更好的预警措施。
The North Atlantic and Europe experienced two extreme climate events in 2015: exceptionally cold ocean surface temperatures and a summer heat wave ranked in the top ten over the past 65 years. Here, we show that the cold ocean temperatures were the most extreme in the modern record over much of the mid-high latitude North-East Atlantic. Further, by considering surface heat loss, ocean heat content and wind driven upwelling we explain for the first time the genesis of this cold ocean anomaly. We find that it is primarily due to extreme ocean heat loss driven by atmospheric circulation changes in the preceding two winters combined with the re-emergence of cold ocean water masses. Furthermore, we reveal that a similar cold Atlantic anomaly was also present prior to the most extreme European heat waves since the 1980s indicating that it is a common factor in the development of these events. For the specific case of 2015, we show that the ocean anomaly is linked to a stationary position of the Jet Stream that favours the development of high surface temperatures over Central Europe during the heat wave. Our study calls for an urgent assessment of the impact of ocean drivers on major European summer temperature extremes in order to provide better advance warning measures of these high societal impact events.