Garfinkel Chaim I, Son Seok-Woo, Song Kanghyun, Aquila Valentina, Oman Luke D
The Fredy and Nadine Herrmann Institute of Earth Sciences Hebrew University of Jerusalem Jerusalem Israel.
School of Earth and Environmental Sciences Seoul National University Seoul South Korea.
Geophys Res Lett. 2017 Jan 16;44(1):374-382. doi: 10.1002/2016GL072035. Epub 2017 Jan 7.
The recent hiatus in global-mean surface temperature warming was characterized by a Eurasian winter cooling trend, and the cause(s) for this cooling is unclear. Here we show that the observed hiatus in Eurasian warming was associated with a recent trend toward weakened stratospheric polar vortices. Specifically, by calculating the change in Eurasian surface air temperature associated with a given vortex weakening, we demonstrate that the recent trend toward weakened polar vortices reduced the anticipated Eurasian warming due to increasing greenhouse gas concentrations. Those model integrations whose stratospheric vortex evolution most closely matches that in reanalysis data also simulate a hiatus. While it is unclear whether the recent weakening of the midwinter stratospheric polar vortex was forced, a properly configured model can simulate substantial deviations of the polar vortex on decadal timescales and hence such hiatus events, implying that similar hiatus events may recur even as greenhouse gas concentrations rise.
近期全球平均地表温度变暖的中断表现为欧亚大陆冬季降温趋势，而这种降温的原因尚不清楚。在此我们表明，观测到的欧亚大陆变暖中断与平流层极涡近期趋于减弱的趋势有关。具体而言，通过计算与给定极涡减弱相关的欧亚大陆地表气温变化，我们证明，近期极涡减弱的趋势减少了因温室气体浓度增加而预期的欧亚大陆变暖。那些平流层涡旋演变与再分析数据最接近的模式积分也模拟出了变暖中断。虽然尚不清楚冬季平流层极涡近期的减弱是否是受强迫的，但一个配置恰当的模式能够在年代际时间尺度上模拟出极涡的大幅偏差，进而模拟出此类变暖中断事件，这意味着即便温室气体浓度上升，类似的变暖中断事件仍可能再次发生。
