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

这项研究将调查南极坡锋和大陆坡面形态如何决定陆架与深海之间的质量、热量和淡水交换，特别是那些导致致密水流出到邻近盆地的中深层和世界海洋环流的交换。尽管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，但这些水团进入深海环流的过程却没有。因此，这项工作的主要目标是查明支配陆架改造的致密水向邻近深海的中层和深层转移的主要物理过程。同时，它试图理解海洋制度中的补充性极地水流。上陆坡已被确定为大陆架和深海水域交换的关键门户。在这里，与几乎无处不在的锋面有关的地形、速度和密度场肯定会强烈影响大陆架和海洋制度之间的平流和湍流水性质的转移。这项研究有四个具体目标：[1]确定平均锋面结构和变化的主要尺度，并估计锋面对跨坡交换和相邻水团混合的作用；[2]确定坡面地形和水深测量对稠密陆架水锋面位置和外流的影响；[3)确定锋面不稳定、海底边界层输送、潮汐和其他振荡过程对跨坡平流和通量的影响；和[4]评估日混合、通过侵入确定的横向混合以及状态方程中的非线性对流出的接近冰冻的大陆架水的下降率和命运的影响。

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.