Not All Ocean Heat Transport Changes Are Created Equal

海洋热传输（OHT）的变化与海洋和大陆的气候变化有关。信号，如大西洋多年代际振荡（在北大西洋的平均表面温度的振荡），驱动了欧洲上空的干燥/潮湿的条件，被认为主要是由大西洋翻转环流和相关的OHT的流域范围内的波动产生。OHT和异常气候条件之间联系的核心是一系列事件：OHT的变化导致海洋热含量（OHC）在广泛深度范围内的变化，这反过来又改变了海表温度（SST）。OHT的变化最终是通过这种SST修正来影响大气环流的，但OHT-OHC-SST的变化链并不是系统的。事实上，很可能大部分OHT变率只会导致弱SST变化，因此对气候的影响很小。我们目前对OHT变化和气候变率之间联系的理解主要基于气候模式模拟的统计分析。我们的建议是，我们需要更好地了解这种联系背后的机制，以便能够了解有限的可用观测可以告诉我们海洋对真实的世界气候的影响，以及我们的气候模型是否是后者的良好近似。具体来说，这里有几个关键问题，我们希望解决：是什么使OHT气候变化的重要性和潜在的相关社会？OHT-OHC-SST链在海洋和气候模式中是否得到正确的表示？对政府和企业的许多环境政策最相关的1至10年时间尺度的未来气候变化预测有什么影响？为了解决这个问题，我们建议探索海洋内部动力学，限制OHT-OHC-SST链及其在气候预测系统中的代表。该项目的一个重要创新是提出了一种评估OHT变化潜在气候影响的方法，用于解释英国资助的RAPID项目及其后续项目长达10年的经向翻转环流和相关OHT变化的观测结果。我们将结合联合收割机对次表层海洋观测的分析（Argo数据集）和海洋再分析产品，一种使用理想化模型的建模方法（研究物理过程）和现实配置（最容易与气候模型和观测联系起来），以及对全球气候模式和年代际预测产品的评估。除了为英国资助的项目的成功做出贡献外，（如上面提到的快速，但也即将OSNAP），这项研究也将有利于英国社区在评估和潜在的改进英国气候模型和预测系统（UKESM 1/NEMO，气象局DePreSys）。

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).