Understanding Causes and Effects of Changes in the Atmospheric Circulation

了解大气环流变化的原因和影响

• 批准号: RGPIN-2020-06286
• 负责人: Tandon, Neil
• 金额: $ 2.19万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=718184
• 关键词: Understanding; Causes; Effects; Changes; Atmospheric

As human activities warm the planet, there is an urgent need to understand the consequences for specific regions. Circulation of air in the atmosphere exerts a strong influence over regional climate: ascending air typically generates precipitation, whereas descending air is typically very dry. As the planet warms, the strength and spatial structure of the atmosphere's circulation is changing, with important consequences for regional patterns of precipitation and dryness. Many questions remain about the physical mechanisms responsible for these circulation changes and the extent to which these changes will influence regional climate. Thus, I am proposing a research program to develop the fundamental understanding of these mechanisms. Such understanding will produce valuable improvements in climate models and greater confidence in climate model projections. For this funding period, the key objectives of my proposed program are: Objective 1: Examine the circulation mechanisms driving long-term changes in extreme precipitation using a state-of-the-art high-resolution model confined to a 128 km by 128 km region. Such a configuration gives us more control over physical inputs to the regional model, thus generating new discoveries regarding what characteristics of those inputs are most consequential for regional changes of extreme precipitation. Objective 2: Compare the spatial structure of swirling motions (“eddies”) during extreme precipitation events in observational estimates and simulations of regional climate models. Such work will provide a critical test of models' ability to capture key characteristics of the atmospheric circulation relevant for extreme precipitation in the real world. Objective 3: Test the sensitivity of circulation and precipitation changes to climate model parameters that approximate small-scale vertical motions called “convective updrafts.” The current generation of global climate models struggle to accurately simulate the effects of convective updrafts, and our work will discover possible consequences for the simulation of extreme precipitation changes. Objective 4: Examine mechanisms that produce two-way interaction, or “coupling,” between clouds and the atmospheric circulation. Different climate models produce different cloud-circulation coupling strength, and this in turn strongly influences how the atmospheric circulation shifts in space over the long-term, with important consequences for regional precipitation. These objectives serve as important steps towards making transformative improvements in model projections of regional climate change. My past work in this area has already stimulated engagement with federal and municipal government in Canada, and the impact of the proposed work will be felt by a range of stakeholders inside and outside Canada (e.g. policymakers, structural engineers, the agriculture industry, insurance companies) with strong interest in anticipating and adapting to regional climate change.

随着人类活动使地球变暖，迫切需要了解大气中的空气循环对区域气候产生重大影响：上升的空气通常会产生降水，而下降的空气通常非常干燥。随着地球变暖，大气环流的强度和空间结构正在发生变化，对区域降水和干旱模式产生重要影响，关于导致这些环流变化的物理机制以及这些变化对区域气候的影响程度，仍然存在许多问题。因此，我提出一个研究计划，以加深对这些机制的基本了解。这种了解将对气候模型产生有价值的改进，并增强对气候模型预测的信心。在本资助期间，我提出的计划的主要目标是： 目标 1：使用仅限于 128 公里 x 128 公里区域的最先进的高分辨率模型检查驱动极端降水长期变化的环流机制，这种配置使我们能够更好地控制对大气的物理输入。区域模型，从而产生关于这些输入的哪些特征对极端降水的区域变化最重要的新发现。 目标 2：在区域气候模型的观测估计和模拟中比较极端降水事件期间旋转运动（“涡流”）的空间结构。此类工作将为模型捕获与大气环流相关的关键特征的能力提供关键测试。现实世界中的极端降水。 目标 3：测试环流和降水变化对近似小规模垂直运动（称为“对流上升气流”）的气候模型参数的敏感性当前一代的全球气候模型难以准确模拟对流上升气流的影响，我们的工作将发现模拟极端降水变化可能产生的后果。 目标 4：研究云与大气环流之间产生双向相互作用或“耦合”的机制。不同的气候模型产生不同的云-环流耦合强度，这反过来又强烈影响大气环流在太空中的变化。长期来看，对区域降水有重要影响。 这些目标是对区域气候变化模型预测进行变革性改进的重要步骤，我过去在这一领域的工作已经促进了与加拿大联邦和市政府的接触，拟议工作的影响将被一系列人所感受到。加拿大国内外的利益相关者（例如政策制定者、结构工程师、农业、保险公司）对预测和适应区域气候变化有浓厚的兴趣。