Lim Young-Kwon, Cullather Richard I, Nowicki Sophie M J, Kim Kyu-Myong
Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA.
Goddard Earth Sciences Technology and Research/I. M. Systems Group, Greenbelt, MD, 20771, USA.
Sci Rep. 2019 Mar 5;9(1):3481. doi: 10.1038/s41598-019-39896-7.
The inter-relationship between subtropical western-central Pacific sea surface temperatures (STWCPSST), sea ice concentrations in the Beaufort Sea (SICBS), and the North Atlantic Oscillation (NAO) in summer are investigated over the period 1980-2016. It is shown that the Arctic response to the remote impact of the Pacific SST is more dominant in recent summers, leading to a frequent occurrence of the negative phase of the NAO following the STWCPSST increase. Lag-correlations of STWCPSST positive (negative) anomalies in spring with the negative (positive) NAO and SICBS loss (recovery) in summer have increased over the last two decades, reaching r = 0.4-0.5 with significance at the 5 percent level. Both observations and the atmospheric general circulation model experiments suggest that the positive STWCPSST anomaly and subsequent planetary-scale wave propagation act to increase the Arctic upper-level geopotential heights and temperatures in the following season. This response extends to Greenland, providing favorable conditions for developing the negative phase of the NAO. Connected with this atmospheric response, SIC and surface albedo decrease with an increase in the surface net shortwave flux over the Beaufort Sea. Examination of the surface energy balance (radiative and turbulent fluxes) reveals that surplus energy that can heat the surface increases over the Arctic, enhancing the SIC reduction.
研究了1980 - 2016年期间夏季亚热带中西太平洋海表温度（STWCPSST）、波弗特海海冰浓度（SICBS）和北大西洋涛动（NAO）之间的相互关系。结果表明，在最近的夏季，北极对太平洋海温远程影响的响应更为显著，导致STWCPSST升高后NAO负相位频繁出现。在过去二十年中，春季STWCPSST正（负）异常与夏季负（正）NAO以及SICBS减少（恢复）之间的滞后相关性增加，达到r = 0.4 - 0.5，在5%水平上具有显著性。观测和大气环流模式实验均表明，STWCPSST正异常及随后的行星尺度波传播会使下一季北极高层位势高度和温度升高。这种响应延伸至格陵兰岛，为NAO负相位的发展提供了有利条件。与这种大气响应相关，随着波弗特海表面净短波通量增加，海冰浓度和地表反照率降低。对地表能量平衡（辐射和湍流通量）的研究表明，可以加热地表的过剩能量在北极地区增加，加剧了海冰浓度的降低。
