Shelf and Bottom Water Formation Near East Antarctic Polynyas and Glaciers

本研究将探讨相对温暖的环极深水周期性冲刷如何影响南极大陆架致密水团的形成，以及暖水的侵入是否会加快南极致密水的形成速度。这项研究包括观察南极洲东部阿德利海岸外大陆架上的水团变化过程，该大陆架靠近默茨和尼尼斯冰川舌附近的准永久开放水域，即所谓的默茨多冰区。由于新形成的冰被吹向大海，使得更多的冰沿着海岸形成，而且由于冻结过程增加了大陆架水的盐度，因此，由强劲的离岸风形成的南极海岸冰丛通常被称为主要的海冰和盐“工厂”。薄冰，甚至是开阔的水域，意味着大量的热量从海洋流失到大气中，这也增加了陆架水的密度。陆架的水下沉，填满底部的洼地，在重力的作用下顺着大陆斜坡而下。本研究确定了一个额外的过程，预计将在该地区发挥作用：相对温暖的水侵入大陆架，覆盖大陆架水，并从根本上关闭致密化过程。这项研究将利用RVIB Nathaniel B. Palmer在南部夏季沿乔治五世海岸的大陆架和斜坡上获得一个紧密间隔的水文测点阵列。这里获得的数据将补充澳大利亚国家南极计划的一个类似的冬季研究

9909374FairbanksThis study will investigate how the formation of dense water masses on the antarctic continental shelves is affected by the periodic flushing by relatively warm circumpolar deep water, and whether the intrusion of warm water cna enhance the rate of formation of dense antarctic water. The study involves the observation of water mass modification processes on the continental shelf off the Adelie Coast in East Antarctica, near a quasi-permanent area of open water in the vicinity of the Mertz and Ninnis Glacier tongues - the so-called Mertz polynya.Antarctic coastal polynyas, formed by strong offshore winds, are often referred to as major sea ice and salt "factories" because the newly formed ice is blown seaward, allowing more ice to be formed along the coast, and because the freezing process increases the salinity of the continental shelf water. The thin ice, or even open water, implies significant heat losses from the ocean to the atmosphere, which also increases the density of the shelf water. The shelf water sinks, fills any depressions in the bottom, and is gravitationally driven down the continental slope. An additional process is identified for this study and is expected to be at work in this area: the intrusion of relatively warm water onto the continental shelf, overriding the shelf water and essentially shutting down the densification processes. The study will make use of the RVIB Nathaniel B. Palmer to obtain a closely spaced array of hydrographic stations over the continental shelf and slope along the George V Coast in the austral summer. The dat obtained here will complement a similar winter study by the Australian National Antarctic Program.***