Adjoint sensitivity of sea-level and inter-basin transports to surface forcing and circulation anomalies in present and future climates

海平面上升是未来气候变化的少数几个无可争议的因素之一，无论未来的排放情况如何，我们都已经做出了承诺。对下个世纪区域海平面变化的预估与对全球海平面上升的预估在幅度上相似。然而，在其模式、幅度和根本原因的模型预测之间存在着巨大的差异。这个项目的主要目的是确定区域海平面变化以及与之相关的海洋环流变化对地表热通量、淡水通量和动量通量、对远程环流异常以及对不确定模式参数的敏感性。这些敏感性将根据当前气候和各种未来气候情景确定。我们将使用最先进的海洋模型及其所谓的“伴随物”来有效地确定这些敏感性。传统的建模研究中，必须进行大量的实验来确定模型输出对模型输入的灵敏度，与此相反，伴随模型仅从单个模型运行中提供这些灵敏度。这个项目很及时，因为它解决了政府间气候变化专门委员会（ipcc）上个月发布的报告中提出的一些关键问题，这些问题涉及海平面变化和环流预测的不确定性。该报告还借鉴了该团队在利用海洋模型及其附属产品（通过当前nerc资助的项目）方面积累的专业知识和成功经验，将大西洋翻转环流中观测到的变化归因于本地和远程表面强迫。

Sea level rise is one of the few undisputed elements of future climate change to which we are already committed regardless of future emissions scenario. Projections for regional sea level change over the next century are similar in magnitude to those for global sea level rise. Yet there are wide discrepancies between model projections of its pattern, amplitude and the underlying causes. The broad aim of this project is to determine the sensitivities of regional sea level changes, and associated changes in ocean circulation, to surface fluxes of heat, freshwater and momentum, to remote circulation anomalies, and to uncertain model parameters. These sensitivities will be determined for both the present climate and various future climate scenarios. We will use a state of the art ocean model and its so-called 'adjoint' to efficiently determine these sensitivities. In contrast to traditional modelling studies, in which a large number of experiments must be performed to determine the sensitivity of a model output to model inputs, the adjoint model provides each of these sensitivities from just a single model run. The project is timely in that it addresses key issues identified in the Intergovernmental Panel for Climate Change report, released last month, concerning uncertainties in projections of sea level change and circulation. It also draws on the expertise and success that the team has built up in using the ocean model and its adjoint through a current NERC-funded project to attribute changes observed in the overturning circulation in the Atlantic to local and remote surface forcing.