Improved projections of winds at the crossroads between Antarctica and the Southern Ocean

南极洲沿海地区将南大洋与南极大陆连接起来，也是控制南极洲对全球气候系统影响的许多关键相互作用发生的地方。科学家们已经研究了南大洋和南极大陆上空中纬度的风，但对南极洲近海的海风的关注要少得多。海洋和大气的数值模型现在运行在足够小的网格上，可以可靠地解析和表示这些沿海风。然而，这需要在当前一代气候模型中进行测试。由于以下原因，气候模型必须很好地代表这些沿海风：-沿海风影响南极主要冰川的流速及其对全球海平面的相关影响。-沿海Polynyas(冰层中未结冰的海域)上方的风推动世界海洋中密度最高的水-南极底层水(AABW)的降温和下沉，这有助于储存人类释放到大气中的额外热量和碳。-气候模型中的真实地面风场需要产生真实的海冰分布。这对于通过限制海洋表面的蒸发和热损失来控制汇聚到南极大陆的热量和水分的量是重要的。此外，由于海冰的形成使表层水域富含盐分，因此它是稠密的AABW形成和下沉所不可或缺的。对AMCW未来变化的可靠预测以及相关的区域和全球影响，将要求它们在气候模型中具有现实的代表性。我们将利用一个新的最先进的气候模式输出集合，耦合模式对比项目第六阶段(CMIP6)。与英国气象局合作，使用其IPCC级统一模型(MetUM)进行的敏感性研究将使我们能够了解AMCW对模型配置变化的敏感性。这将告诉我们，气候模型需要正确的物理过程才能准确地表示AMCW的结构和可变性。我们将改进对南极站、研究和补给船、漂流浮标和卫星海风的评估，以评估一系列不同网格风场数据产品的质量，这些产品基于观测和观测约束的数值模拟。表现最好的产品将用于评估气候模型的性能。模型评估的既定框架是气候模型“指标”的概念，它可以量化气候系统的关键过程或特征，通常只有一个值，可以根据模型输出和观测参考数据(在我们的情况下，是基于观测的风能产品)计算得出。我们将开发和使用指标来评估CMIP6模型在表示AMCW方面的性能，包括参与其高分辨率子项目HighResMIP的配置。这一点，加上对过程理解的改进，将有助于减少对未来变化预测的不确定性。研究成果将是：-从最新的气候和地球系统模型改进对21世纪AMCW的预测。-可应用于网格气候模型输出的AMCW的观测度量。-根据NERC管弦乐团项目对南极洲沿海海洋进行的历史现场气象观测数据集。-确定南极沿海地区当前一代风力产品中的最佳产品。-结合计划中的敏感性研究，最终应有助于加速模型开发。-两名早期职业研究人员的职业发展，提供气候建模、分析大型数据集、网络和通信技能方面的经验。

The coastal region of Antarctica links the Southern Ocean to the Antarctic continent and is where many of the key interactions that govern Antarctica's impact on the global climate system take place. Scientists have studied winds at mid-latitudes over the Southern Ocean and over the Antarctic continent, but much less attention has been paid to the marine winds just offshore from Antarctica. Numerical models of the ocean and atmosphere are now run on small enough grids that these coastal winds can be resolved and represented reliably. However, this needs to be tested in the current generation of climate models. It is important that climate models have a good representation of these coastal winds for the following reasons: - Coastal winds influence the flow rate of major Antarctic glaciers and their associated impacts on global sea level. - Winds over coastal polynyas (areas of unfrozen sea within the ice pack) drive cooling and sinking of the densest water in the world ocean, known as Antarctic Bottom Water (AABW), which contributes to storing the extra heat and carbon released into the atmosphere by humans. - Realistic surface wind fields in climate models are needed to produce realistic distributions of sea ice. This is important in controlling the amount heat and moisture convergence into the Antarctic continent by capping off evaporation and heat loss from the ocean surface. Additionally, since sea ice formation enriches surface waters with salt, it is integral to the formation and sinking of dense AABW. Reliable projections of future change in AMCWs, and related regional and global impacts, will require their realistic representation in climate models. We will make use of a new collection of state-of-the-art climate model output, the Coupled Model Inter-comparison Project Phase 6 (CMIP6). In collaboration with the Met Office, sensitivity studies using their IPCC-class Unified Model (MetUM) will enable us to understand how sensitive AMCWs are to changes in model configuration. This will tell us which physical processes climate models need to get right to accurately represent the structure and variability of AMCWs. We will improve the evaluation of observed winds from Antarctic stations, research and supply vessels, drifting buoys, and marine winds from satellites to assess the quality of a range of different gridded wind data products, which are based on both observations and observationally-constrained numerical modelling. The best performing products will be used to evaluate climate model performance. An established framework for model evaluation is the concept of climate model 'metrics', which can quantify a key process or feature of the climate system, usually with a single value, that can be calculated from both model output and observational reference data (in our case observationally-based wind products). We will develop and use metrics to evaluate the performance of CMIP6 models in representing AMCWs, including configurations participating in its high-resolution sub-project HighResMIP. This, along with improved process understanding, will help to reduce uncertainty in projections of future change.The research outcomes will be: - Improved 21st century projections of AMCWs from the latest state-of-the-art climate and earth system models.- Observational metrics of AMCWs that can be applied to gridded climate model output. - A dataset of historical in-situ meteorological observations of marine coastal Antarctica building on the NERC ORCHESTRA project.- Identify the best of the current generation of wind products for the Antarctic coastal region. - Evaluation of the representation of AMCWs in the MetUM which, in combination with planned sensitivity studies, should ultimately facilitate accelerated model development.- Career development for two early career researchers giving experience in climate modelling, analysing large datasets, networking and communication skills.