Modelling of the Wyville Thomson Ridge overflow

威维尔·汤姆森岭溢流的建模

• 批准号: NE/F012489/1
• 负责人: Toby Sherwin
• 金额: $ 1.65万
• 依托单位: Scottish Association For Marine Science
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF012489%2F1
• 关键词: Modelling; Wyville; Thomson; Ridge; overflow

The exchange of water between the Nordic Seas and the North Atlantic Ocean is part of the global thermo-haline circulation in which warm, saline water flows northwards in the near/surface layers while cold fresher water returns southwestwards at depth. The strength and variability of this circulation is thought to have significant consequences for the climate of northern Europe. Important exit pathways for the cold, dense bottom water are found all along the topographic barrier presented by the Greenland Scotland Ridge - the eastern section of which (between Iceland and Scotland) carries about one third of the total overflow transport into the N Atlantic. The proposed modelling project will focus on the portion of the overflow that is diverted from the Faroe Bank Channel and over the Wyville-Thomson Ridge (WTR), eventually into the Rockall Trough. The climatic importance of this branch of the overflow is already recognised by the establishment by NERC of a field monitoring programme at the site. Sets of mathematical and laboratory models will be developed to support the monitoring activity, in order to understand the processes responsible for the leakage of flow over the WTR and the pathways taken by the overflow as it crosses the WTR and finds its way to the Rockall Trough. Furthermore, the models will quantify the relative fluxes of dense bottom water overflows at different sections of the ridge under different external conditions and will explore the conditions under which the overflow is episodic in nature. The topographic control on the coupling between (i) the overflow leakage over the ridge and (ii) the main overflow transport in the adjacent Faroe Bank Channel is of crucial importance for the resolution of the above matters and this will receive special attention in the modelling studies. The processes responsible for variability in the Wyville Thomson Ridge overflow will be delineated and the mixing associated with the final cascading descent of bottom water into the Rockall Trough will be measured for a wide range of conditions. The models will vary in domain size, from the regional scale, in which the overflow characteristics of a large part of the Faroese Channels system will be simulated, to the small scale where the detailed structure of the cascading flow and its mixing with the overlying warmer waters will be studied. An important aspect of the research is the interplay between the modelling investigations and the field data, with the predictions of the former informing the analysis of the latter and the future development of the monitoring operations.

北欧海和北大西洋之间的水交换是全球热盐环流的一部分，其中温暖的咸水在近/表层向北流动，而寒冷的淡水在深层向西南回流。这种环流的强度和变化被认为对北欧的气候有重大影响。寒冷、稠密的底层水的重要出口通道位于格陵兰苏格兰脊所呈现的地形屏障上——它的东段（在冰岛和苏格兰之间）将大约三分之一的溢流输送到北大西洋。拟议的建模项目将重点关注从法罗银行海峡转移的溢流部分，并越过威维尔-汤姆森山脊（WTR），最终进入罗克尔海槽。这一支流溢流的气候重要性已经被NERC在现场建立的现场监测方案所认识到。将开发一套数学模型和实验室模型来支持监测活动，以便了解造成WTR上水流泄漏的过程，以及溢流穿过WTR并进入罗克尔槽的途径。此外，模型将量化不同外部条件下脊不同部分密集底水溢流的相对通量，并将探索溢流是偶发性的条件。地形对(i)山脊上的溢流泄漏和（ii）邻近法罗河岸通道的主要溢流运输之间耦合的控制对于解决上述问题至关重要，这将在建模研究中得到特别关注。将描述导致Wyville Thomson Ridge溢流变化的过程，并在广泛的条件下测量与底水最终级联下降到Rockall槽相关的混合。这些模型的范围大小各不相同，从区域尺度，法罗群岛水道系统的大部分溢流特征将被模拟，到小尺度，级联流的详细结构及其与上覆的温暖水域的混合将被研究。研究的一个重要方面是模拟调查和实地数据之间的相互作用，前者的预测为后者的分析和监测业务的未来发展提供了信息。