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

改进了南极洲和南大洋交界处的风预测

• 批准号: NE/V000691/1
• 负责人: Thomas Bracegirdle
• 金额: $ 69.93万
• 依托单位: British Antarctic Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FV000691%2F1
• 关键词: Improved; projections; winds; crossroads; between

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.

南极洲的沿海地区将南大洋与南极大陆联系起来，这是统治南极对全球气候系统影响的许多关键相互作用的地方。科学家们在南大洋和南极大陆上的纬度中期研究了风，但是对来自南极洲近海的海洋风的关注要少得多。现在，海洋和大气的数值模型在足够小的网格上运行，以至于可以可靠地解决这些沿海风。但是，这需要在当前的气候模型中进行测试。由于以下原因，重要的是，气候模型对这些沿海风有很好的代表： - 沿海风影响南极主要冰川的流量及其对全球海平面的相关影响。 - 在沿海Polynyas（冰袋内未冻海的地区）驱动冷却和下沉世界海洋中最密集的水，被称为南极底水（AABW），这有助于将人类释放到大气中的额外热量和碳。 - 需要在气候模型中逼真的表面风场来产生海冰的现实分布。这对于控制热量和水分收敛到南极大陆很重要，这是通过封闭海面蒸发和热量损失来控制南极大陆的。此外，由于海冰形成富含盐水，因此它是密集AABW的形成和下沉不可或缺的一部分。对AMCW的未来变化以及相关的区域和全球影响的可靠预测将需要在气候模型中进行现实的代表。我们将利用最新的气候模型输出的新集合，即耦合模型间比较项目阶段6（CMIP6）。通过与MET办公室的合作，使用其IPCC级统一模型（Metum）的灵敏度研究将使我们能够了解AMCW对模型配置的变化的敏感性。这将告诉我们需要哪些物理过程气候模型才能正确代表AMCW的结构和可变性。我们将改善对南极站，研究和供应容器，漂流浮标以及卫星风的海洋风的评估，以评估一系列不同的网格风数据产品的质量，这些数据产品基于观察值和观察构成的数值建模。最佳性能产品将用于评估气候模型性能。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，通常具有单个值，可以从模型输出和观察性参考数据（在我们的案例基于观察的风能中）进行计算。我们将开发和使用指标来评估CMIP6模型在表示AMCW中的性能，包括参与其高分辨率子项目highresmip的配置。这将有助于减少未来变化预测的不确定性。研究结果将是： - 从最新的最新气候和地球系统模型中改进了AMCW的21世纪预测。-可将AMCW的观察指标应用于网格气候模型。 - NERC乐团项目上海洋沿海南极建筑的历史现场气象观察数据集。 - 评估元中AMCW的表示，结合计划的敏感性研究，该元件最终应促进加速模型的发展。-两位早期职业研究人员的职业发展提供了气候建模，分析大型数据集，网络和沟通技巧的经验。