Not All Ocean Heat Transport Changes Are Created Equal

并非所有海洋热传输变化都是一样的

• 批准号: NE/P002250/1
• 负责人: David Ferreira
• 金额: $ 39.16万
• 依托单位: University of Reading
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FP002250%2F1
• 关键词: Ocean; Heat; Transport; Changes; Created

Changes in Ocean Heat Transport (OHT) have been associated with changes in climate over the oceans and continents. Signals such as the Atlantic Multidecadal Oscillation (an oscillation of the averaged surface temperature in the North Atlantic ocean), which drives anomalously dry/wet conditions over European, are thought to be primarily generated by basin wide fluctuations in the Atlantic Overturning Circulation and associated OHT. At the core of the link between OHT and anomalous climate conditions is a chain of events: changes in OHT result in changes in the Ocean Heat Content (OHC) over a broad range of depths, which in turn modifies the Sea Surface Temperature (SST). It is ultimately through this SST modification that the OHT changes can influence the atmospheric circulation.It has to be emphasized, however, that the OHT-OHC-SST chain is not systematic. In fact, it is likely that a large fraction of the OHT variability does only result in weak SST changes and thus little climate impact. Our current understanding of the link between OHT changes and climate variability is primarily based on statistical analyses of climate model simulations. Our proposal is that we need to understand better the mechanisms behind this link to be able to understand what the limited available observations can tell us about the ocean's impact on climate in real world, and whether or not our climate models are good approximations of the latter. Specifically, here are a few key questions that we wish to address: What makes an OHT change climatically important and potentially relevant to society? Is the OHT-OHC-SST chain properly represented in ocean and climate models? What are the implications for predictions of future climate change on the 1 to 10 year timescale of most relevance to many environmental policies of governments and businesses? To address this, we propose to explore the ocean interior dynamics that constrains the OHT-OHC-SST chain and its representation in climate prediction systems. An important innovation of the project is a methodology to evaluate the potential climate impact of OHT changes, to be used to interpret decade-long observations of the Meridional Overturning Circulation and associated OHT changes by the UK funded RAPID project and its successors.We will combine an analysis of subsurface ocean observations (Argo dataset) and ocean reanalysis products, a modeling approach with idealized models (to study physical processes) and realistic configurations (to link most readily with climate models and observations), and an evaluation of a global climate model and decadal prediction products.Besides contributing to the success of UK-funded projects (like RAPID mentioned above, but also the upcoming OSNAP), this research will also benefit the UK community in terms of evaluation and potential improvements of the UK climate models and prediction systems (UKESM1/NEMO, Met Office DePreSys).

海洋热传输(OHT)的变化与海洋和大陆的气候变化有关。诸如大西洋数十年振荡(北大西洋平均表面温度的振荡)这样的信号，在欧洲上空造成异常的干/湿条件，被认为主要是由大西洋翻转环流和相关的OHT中的盆地范围波动产生的。OHT和异常气候条件之间联系的核心是一系列事件：OHT的变化导致大范围深度的海洋热含量(OHC)的变化，这反过来又改变了海表面温度(SST)。但必须强调的是，OHT-OHC-SST链并不是系统性的。事实上，很可能很大一部分OHT变异性只会导致较弱的SST变化，因此对气候的影响很小。我们目前对OHT变化和气候变异性之间的联系的理解主要是基于对气候模型模拟的统计分析。我们的建议是，我们需要更好地了解这种联系背后的机制，以便能够理解有限的可用观测可以告诉我们什么，关于海洋对现实世界气候的影响，以及我们的气候模型是否很好地近似于后者。具体地说，这里有几个我们希望解决的关键问题：是什么使OHT变化在气候上具有重要意义，并可能与社会相关？海洋和气候模型中是否恰当地表示了OHT-OHC-SST链？在与政府和企业的许多环境政策最相关的1至10年时间尺度上，对未来气候变化的预测有什么影响？为了解决这个问题，我们建议探索限制OHT-OHC-SST链的海洋内部动力学及其在气候预测系统中的表示。该项目的一个重要创新是评估OHT变化的潜在气候影响的方法，用于解释英国资助的RAPID项目及其后续项目对子午线翻转环流和相关OHT变化的长达十年的观测。我们将结合对海底海洋观测(ARGO数据集)和海洋再分析产品的分析，采用理想化模式(研究物理过程)和现实配置(最容易与气候模式和观测联系在一起)的建模方法，以及对全球气候模式和十年预测产品的评估。此外，还将为英国资助的项目(如上文提到的RAPID，以及即将到来的OSNAP)的成功做出贡献。这项研究还将使英国社区受益于英国气候模型和预测系统(UKESM1/NEMO，Met Office DePreSys)的评估和潜在改进。