全球变暖下南大洋吸热的季节变化特征  

Characteristics of Seasonal Variation of the Southern Ocean Heat Uptake Under Global Warming

作　　者：罗菁 郑小童 Luo Jing;Zheng Xiaotong(The Key Laboratory of Physical Oceanography,Ministry of Education,College of Oceanic and Atmosphere Sciences,Ocean University of China,Qingdao 266100,China;Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China)

机构地区：[1]中国海洋大学物理海洋教育部重点实验室,海洋与大气学院,山东青岛266100 [2]青岛海洋科学与技术试点国家实验室,山东青岛266237

出　　处：《中国海洋大学学报（自然科学版）》2024年第3期9-19,共11页Periodical of Ocean University of China

基　　金：国家重点研究发展计划项目(2018YFA0605704)资助。

摘　　要：本文基于第六次耦合模式比较计划的未来高排放情景试验模拟结果,研究全球变暖背景下未来南大洋吸热的季节变化。发现在未来变暖气候下南大洋占全球海洋累积吸热的近一半。未来南大洋海洋吸热有明显季节变化:南半球春、秋季吸热峰值大致位于63°S,夏季70°S附近吸热最小,冬季58°S附近吸热全年最大。秋、冬季海洋吸热的空间结构由湍流热通量主导;春、夏季高纬度海洋吸热主要受辐射通量影响。进一步研究发现,南大洋60°S以南海区净热通量变化趋势与海冰变化有关。春、夏季海冰消融通过海冰-反照率反馈机制产生较大的海洋吸热,而秋、冬季海冰消融加强了海洋向大气放热,造成海洋吸热减少,年平均下二者显著抵消。在南大洋30°S—60°S海区,海洋吸热主要受湍流热通量变化影响,夏、秋季吸热较少,冬、春季吸热较大,这与气候态混合层深度的季节变化有显著关系。此外,本文研究还发现,南大洋上层海洋热量的经向输送对全球变暖的响应也存在显著的季节变化,冬、春季经向热输送的增强范围相较于夏、秋季向赤道和向下延伸,与气候态混合层深度和西风增强的季节变化有关。Based on the high emission scenario experiments from Coupled Model Intercomparison Project phase 6(CMIP6),this study investigates the seasonal variation of future ocean heat uptake(OHU)in the Southern Ocean(SO)under global warming.It is found that the cumulative ocean heat uptake in the SO accounts for nearly half of the global OHU under global warming.The peak of OHU in the SO in spring and autumn locates around 63°S.In summer,it locates around 70°S and shows the lowest OHU.By contrast,it locates around 58°S and shows the largest OHU in winter.The spatial structure of OHU in autumn and winter is dominated by turbulent heat fluxes,while the OHU in high latitude ocean in spring and summer is mainly modulated by radiative fluxes.Further investigations reveal that the trend of net heat flux in the southern part of the SO(south of 60°S)is related to the sea ice melting.In spring and summer,sea ice melting generates larger OHU through the sea ice-albedo feedback,while in autumn and winter,sea ice melting enhances the oceanic heat release to the atmosphere.This results in a decrease in ocean heat uptake.The above two processes counteract with each other in the annual mean results.In the low-latitude oceanic region of the SO(30°S—60°S),OHU is mainly influenced by the turbulent heat fluxes,with less(more)OHU in summer and autumn(winter and spring).This is significantly related to the seasonal variation of the mean mixed layer depth.We also found that there is significant seasonal variation in the response of the meridional heat transport in the SO to global warming.The meridional heat transport trend in winter and spring extends equatorward and downward compared with that in summer and autumn,this is also related to the mean mixed layer depth and zonal wind strengthening.

关 键 词：南大洋 海洋吸热 海气相互作用 全球变暖 季节变化 

分 类 号：P728.1[天文地球—海洋科学]