北极和南极表面温度对中低纬度海洋热强迫的响应

Responses of the Arctic and Antarctic Surface Temperatures to Oceanic Thermal Forcing at the Middle and Low Latitudes

利用耦合了平板海洋模型的全球气候模式进行了大量的格林函数实验,以探究两极地区对于施加在中低纬度海域的热强迫的气候响应。结果表明,北极地区的气候不仅受到距离较近的北太平洋与北大西洋的影响,远离北极的热带太平洋以及南太平洋也对其气候有显著的影响,南极地区的气候则主要是受到邻近的南大洋的影响。通过经验正交函数法的进一步分析发现,北极响应最显著的区域包括波弗特海(Beaufort Sea)、拉普捷夫海(Laptev Sea)以及北极中心区附近;南极地区的响应主要集中在别林斯高晋海(Bellinsgauzen Sea)区域。另外,利用温度归因法对辐射反馈过程和大气能量输运分解发现,北极地区表面温度的响应主要是受到了反照率反馈以及垂直递减率反馈的影响,而南极地区的响应则主要是反照率反馈发挥了作用。

Employing the slab ocean version of Community Earth System Model,we perform a large set of Green’s function-type experiments to explore the climate response over the two polar regions of our planet to thermal forcing placed in different areas of the global oceans.Results show that,for the Arctic,the forcing not only placed in the adjacent North Pacific and North Atlantic but also in the Tropical Pacific and even in the distant Southern Ocean have significant impacts on its surface temperature and sea ice area.In contrast,the surface temperature and sea ice area in the Antarctic are mainly affected by the forcing placed in the Southern Ocean.In other words,the Arctic is more prone to be affected by the forcing from global oceans,while the Antarctic is mainly influenced by adjacent oceans.However,the forcing placed in the subtropics is found to have much less influence on both polar regions.In addition,we perform an empirical orthogonal function analysis to identify the most excitable response of surface temperature and sea ice area to the oceanic thermal forcing.It is found that the most excitable responses appear to be in the Beaufort Sea,Laptev Sea and around the north pole of the Arctic,and in the Bellingshausen Sea of the Antarctic.A further analysis with a radiative kernel-based attribution method finds that the surface temperature response in the Arctic is mainly resulted from the albedo and lapse-rate feedbacks,whereas that in the Antarctic is primarily due to the albedo feedback.