南海深层西边界流的观测与模拟

The deep South China Sea (SCS) circulation made progressive approaches in recent years, but it still needs to be further explored deeply. The variability and mechanism of the western boundary current in the deep SCS is one of the most challenge issues. The proposal will focus on studying the western boundary current in the deep SCS. Based on the mooring arrays deployed recently, we will observe the whole western boundary current with two new moorings. we will study the variability of the western boundary current, reveal its mechanism, and develop its theory with combination methods including data analysis, field observation, numerical simulation and theory analysis. The proposal will help improve our research capacities on the deep western boundary current, and provide some insights to link the deep SCS circulation and sedimental transport, thus it should be valuable for science and reality.

南海深层环流研究最近几年取得了可喜的进展，但仍有许多尚未解决的科学问题。 加强南海深层西边界流时空变化及形成机理的认识则是较为迫切的研究课题之一，面临着许多挑战和机遇。本课题选取“南海深层西边界流”为重点研究对象，拟充分利用已建设的南海锚碇观测阵列，辅予补充观测，组成南海深层西边界流的观测阵列。通过资料分析、补充观测、数值模式和理论分析等综合手段，系统研究南海深层西边界流的时空变化特征，揭示南海深层西边界流的形成机理，发展南海深层西边界流的解析理论。这一项目的实施将提升我国深海西边界流研究水平，也将为建立南海深海环流和深海沉积的有机联系提供重要科学依据，具有重要的科学和实际意义。

通过本项目的研究，深入了解了南海深层西边界流的三维结构特征及其动力机制：.1）南海深层西边界流确实存在，其厚度在240m至2000m之间，平均大约1100m，宽度25km-125km，平均大约44km，流速0.6-6.7cm/s，平均大约1.3cm/s；.2）南海深层西边界流的存在显著的季节内变化以及春季流向反转，可能都与吕宋深海入流有关；.3）阐明了对南海泥沙输运有重要影响的两种上升流/下降流机制，一是吕宋深海入流进入南海后沿着边界边界处上升（逆茶壶效应），二是表层偶极子涡旋锋生引起的四页型升降流分布；.4）南海深海底边界层特征明显，厚度大约为80-100m，边界层的流速可达几十厘米/秒，值得深入探讨。.通过本项目的实施，提升了我国南海深层西边界流观测与理论水平，为建立南海深海环流和深海沉积的有机联系提供重要科学依据。