The fate of freshwater in tidally stirred shelf seas

潮汐搅动的陆架海中淡水的命运

• 批准号: NE/D011566/1
• 负责人: Tom Rippeth
• 金额: $ 27.43万
• 依托单位: Bangor University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FD011566%2F1
• 关键词: fate; freshwater; tidally; stirred; shelf

Regions of continental shelf seas provide a critical interface between estuaries and the ocean across which freshwater, suspended particulate matter, and consequently carbon, nutrients and anthropogenic contaminants are exchanged. Whilst the currents in continental shelf seas are dominated by the tide, it is the normally much weaker, residual circulation which determines the longer term fate of the freshwater. A vital prerequisite to the prediction of the exchange of water (and its load) across these critical interfaces is therefore the identification and quantification of the processes and mechanisms which are responsible for the formation and control of the residual circulation. The classical view is that this circulation is essentially density driven, however recent theoretical work has suggested that a 'tidal asymmetry' in both the level of stratification and the vertical mixing rate (known as tidal straining) greatly enhance the residual circulation. There is limited anecdotal evidence to support this idea. We would also suggest that the failure of state-of-the-art 3-dimensional hydrodynamic models to reproduce the correct distribution of salinity (i.e. freshwater) in these regions is a result of their failure to correctly simulate there tidal straining mechanism. Our proposal is to investigate the importance of tidal straining in determining the off-shore flux of freshwater in shelf seas. The hypothesis 'the off-shore flux of freshwater in tidally stirred shelf seas is largely determined by tidal straining' will be tested through identification and quantification the key processes which determine the fate of freshwater in tidally stirred shelf seas. To acheive this aim we will use coastal observatory observations and state-of-the-art numerical model predictions.

大陆架海洋的区域在河口与海洋之间提供了关键的界面，淡水，悬浮的颗粒物物质以及因此碳，养分和人为污染物被交换。虽然大陆架海洋中的电流主要由潮汐主导，但通常弱的残留循环决定了淡水的长期命运。因此，预测水（及其负载）在这些关键界面上的交换的重要先决条件是鉴定和量化负责剩余循环的过程和机制的过程和机制。经典的观点是，这种循环基本上是密度驱动的，但是最近的理论工作表明，分层和垂直混合速率（称为潮汐拉力）的“潮汐不对称”极大地增强了残留循环。有限的轶事证据可以支持这一想法。我们还建议，最先进的三维流体动力模型的失败是在这些区域重现盐度（即淡水）的正确分布的原因是它们未能正确模拟那里的潮汐拉力机制。我们的建议是调查潮汐紧张在确定货架海中淡水往外通量中的重要性。假设“潮汐搅拌架子海中的淡水的偏离量通量在很大程度上取决于潮汐扭曲”，将通过识别和量化确定潮汐搅拌架子海洋中淡水的命运的关键过程进行测试。为了达到这一目标，我们将使用沿海观测观测和最先进的数值模型预测。