Xu Lixiao, Li Peiliang, Xie Shang-Ping, Liu Qinyu, Liu Cong, Gao Wendian
Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology, Ocean University of China, Qingdao 266100, China.
Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, USA.
Nat Commun. 2016 Feb 1;7:10505. doi: 10.1038/ncomms10505.
While modelling studies suggest that mesoscale eddies strengthen the subduction of mode waters, this eddy effect has never been observed in the field. Here we report results from a field campaign from March 2014 that captured the eddy effects on mode-water subduction south of the Kuroshio Extension east of Japan. The experiment deployed 17 Argo floats in an anticyclonic eddy (AC) with enhanced daily sampling. Analysis of over 3,000 hydrographic profiles following the AC reveals that potential vorticity and apparent oxygen utilization distributions are asymmetric outside the AC core, with enhanced subduction near the southeastern rim of the AC. There, the southward eddy flow advects newly ventilated mode water from the north into the main thermocline. Our results show that subduction by eddy lateral advection is comparable in magnitude to that by the mean flow--an effect that needs to be better represented in climate models.
虽然模型研究表明中尺度涡旋会加强模态水的俯冲作用，但这种涡旋效应在实地从未被观测到。在此，我们报告了2014年3月一次实地考察的结果，该考察捕捉到了日本以东黑潮延伸区以南涡旋对模态水俯冲的影响。该实验在一个反气旋涡（AC）中部署了17个阿尔戈浮标，并加强了每日采样。对跟随该反气旋涡的3000多个水文剖面的分析表明，在反气旋涡核心区之外，位涡和表观耗氧量分布不对称，在反气旋涡东南边缘附近俯冲作用增强。在那里，向南的涡旋流将新通风的模态水从北方平流到主温跃层。我们的结果表明，涡旋侧向平流引起的俯冲作用在量级上与平均流引起的俯冲作用相当——这种效应在气候模型中需要得到更好的体现。
