西太平洋深层西边界流的结构特征和变异规律

Due to the lack of substantial source of dense bottom waters in the North Pacific, all the deep and bottom waters of both the North and South Pacific have their origins in the Antarctic, and are carried northward in a deep western boundary current (DWBC). Study on the Pacific DWBC and its water mass is essential to the understanding of global meridional overturning circulation, heat balance, and climate change. Three datasets, including the comprehensive observations by the Chinese Academy of Sciences in the deep channel near the Yap-Mariana Junction, the historical observations made in different deep channels of the Pacific DWBC, and a global ocean re-analysis product, will be synthesized. The objectives of the present study are 1) to reveal the structure, characteristics and variability of the DWBC in the Western Pacific, and the underlying mechanisms; 2) to illustrate the influence and constraint of the ocean bottom topography on dynamic processes in the deep ocean, and their universal connecting relationship; and 3) to discuss the response of the Pacific DWBC to the climate change based mainly on the difference and similarity of the Pacific DWBC’s behaviors at the same channel of different decades and at different channels of the same decade.

太平洋北半球中高纬度海区没有不断冷却形成的高密度水，其深层和底层水均由深层西边界流携带南极高密水向北输运而来，因此开展太平洋深层西边界流研究对理解全球经向翻转环流、热量平衡和气候变化有重要意义。基于中科院在雅浦-马里亚纳海沟连接深水通道处的综合观测数据、太平洋深层西边界流历史观测数据和再分析数据等，揭示西太平洋深层西边界流和水团的结构特征、变异规律和控制机制；研究地形引起相关动力学行为的过程机制，探寻地形影响深层海洋动力过程的普适性规律；比较分析深层西边界流在同一深水通道不同年代和同一年代不同深水通道结构和变异的异同，讨论太平洋深层西边界流对全球和区域气候变化的响应。

北太平洋没有不断冷却形成的高密度水，其深层和底层水均由深层西边界流携带南极高密水向北输运而来，因此深层西边界流深刻影响着北太平洋深层的热量和碳量，对全球气候变化有重要意义。项目基于观测网获取的数据并结合模式数据，逐步摸清了深层西边界流在雅浦-马里亚纳海沟连接区季节性入侵西太平洋的路径、流量和动力机制，揭示了地形罗斯贝波引起的深层季节内振荡特征和能量来源，发现了深海与上层海洋和气候变化联系的“高速公路”，改变了以往“深海是死水、杂乱无章和非常缓慢变化”的传统认知。基于以上创新性结果，项目发表了10篇高水平SCI论文，受邀发表1篇中文综述性论文。