Collaborative Research: AnSlope, Cross-Slope Exchanges at the Antarctic Slope Front

本研究将探讨南极坡锋和大陆坡形态如何决定大陆架和深海之间的物质、热量和淡水交换，特别是那些导致密集水向邻近盆地的中层和深层流出并进入世界海洋环流的交换。而起源于南极的冷水团对全球海洋环流和气候的重要性是毋庸置疑的。这些水团进入深海环流的过程却不是这样。因此，这项工作的主要目标是确定控制大陆架修饰的致密水向邻近深海的中间层和深层转移的主要物理过程。与此同时，它试图了解来自海洋体制的补偿性水向极地流动。大陆上坡已被确定为陆架与深海水交换的关键门户。在这里，与几乎无处不在的锋面相关的地形、速度和密度场必须强烈地影响陆架和海洋状态之间水性质的平流和湍流转移。该研究有四个具体目标：确定平均锋面结构和变率的主要尺度，并估计锋面对相邻水团的跨坡交换和混合的作用；[2]确定斜坡地形和水深对密集陆架水前缘位置和流出的影响；[3]建立锋面不稳定、底栖边界层输送、潮汐等振荡过程对坡面平流和通量的作用；评估纵向混合、通过侵入确定的横向混合以及状态方程中的非线性对下降速率和流出的接近冰点的陆架水的命运的影响。

This study will investigate how the Antarctic Slope Front and continental slope morphology determine the exchanges of mass, heat, and fresh water between the shelf and the deep ocean, in particular those leading to outflows of dense water into intermediate and deep layers of the adjacent basins and into the world ocean circulation While the importance to the global ocean circulation and climate of cold water masses originating in the Antarctic is unquestioned, the processes by which these water masses enter the deep ocean circulation are not. The primary goal of this work therefore is to identify the principal physical processes that govern the transfer of shelf-modified dense water into intermediate and deep layers of the adjacent deep ocean. At the same time, it seeks to understand the compensatory poleward flow of waters from the oceanic regime. The upper continental slope has been identified as the critical gateway for the exchange of shelf and deep ocean waters. Here the topography, velocity and density fields associated with the nearly ubiquitous front must strongly influence the advective and turbulent transfer of water properties between the shelf and oceanic regimes. The study has four specific objectives: [1] Determine the mean frontal structure and the principal scales of variability, and estimate the role of the front on cross-slope exchanges and mixing of adjacent water masses; [2] Determine the influence of slope topography and bathymetry on frontal location and outflow of dense Shelf Water; [3] Establish the role of frontal instabilities, benthic boundary layer transports, tides and other oscillatory processes on cross-slope advection and fluxes; and [4] Assess the effect of diapycnal mixing, lateral mixing identified through intrusions, and nonlinearities in the equation of state on the rate of descent and the fate of outflowing, near-freezing Shelf Water.