热带太平洋海温异常对北极海冰的可能影响

本文利用1950-2015年间Hadley环流中心海冰和海温资料及NCEP/NCAR再分析资料，研究了热带太平洋海温异常对北极海冰的可能影响，并从大气环流和净表面热通量两个角度探讨了可能的物理机制。结果表明，在ENSO事件发展年的夏、秋季节，EP型与CP型El Niño事件与北极海冰异常的联系无明显信号。而La Niña事件期间北极海冰出现显著异常，并且EP型与CP型La Niña之间存在明显差异。EP型La Niña发生时，北极地区巴伦支海、喀拉海关键区海冰异常减少，CP型La Niña事件则对应着东西伯利亚海、楚科奇海地区海冰异常增加。在EP型La Niña发展年的夏、秋季节，热带太平洋海温异常通过遥相关波列，使得巴伦支海、喀拉海海平面气压为负异常并与中纬度气压正异常共同构成类似AO正位相的结构，形成的风场异常有利于北大西洋暖水的输入，同时造成暖平流，偏高的水汽含量进一步加强了净表面热通量收入，使得巴伦支海、喀拉海海冰异常减少。而在CP型La Niña发展年的夏季，东西伯利亚海、楚科奇海关键区受其东侧气旋式环流的影响，以异常北风分量占主导，将海冰从极点附近由北向南输送到关键区，海冰异常增加，而净表面热通量的作用较小。

The possible influence of sea surface temperature anomalies over the tropical Pacific on the Arctic sea ice

The possible influence of sea surface temperature (SST) anomalies over the tropical Pacific on the Arctic sea ice and their possible mechanisms are researched from atmospheric circulation and net surface heat flux by using monthly data of HadISST and NCEP/NCAR spanning from 1950 to 2015. The main results obtained show that during summer and autumn of ENSO development phase, EP and CP El Niño events have no apparent connection with the Arctic sea ice anomalies. However, strong signals are detected when it happens to La Niña and there are distinctive differences between EP and CP events.Sea ice reduce in Barents/Kara Sea in EP La Niña but increase in East Siberia/Chukchi Sea in CP La Niña. During summer and autumn of EP La Niña''s development, SST anomalies over the tropical Pacific leads to negative SLP in Barents/Kara Sea by teleconnection wave trains and forms AO-like pattern together with positive SLP in middle latitude. It changes the wind which brings warm advection and southerly anomalies helps to transfer more warm water from North Atlantic, high water vapor content at the same time enhance the income of net surface heat flux and result in the decrease of sea ice in Barents/Kara Sea. In the situation of CP La Niña, East Siberia/Chukchi Sea are dominated by north wind in summer because of a cyclonic circulation in the eastern side, sea ice are transported here from North Pole and thus sea ice concentration increased, effect of net surface heat flux is small.