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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751038
• 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，迫切需要了解对特定地区的影响。大气中的空气循环对区域气候有很强的影响：上升的空气通常产生降水，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，对降水和干旱的区域模式产生重要影响。关于造成这些环流变化的物理机制以及这些变化将在多大程度上影响区域气候，仍然存在许多问题。因此，我提出了一个研究计划，以发展对这些机制的基本理解。这种理解将对气候模式产生有价值的改进，并提高气候模式预估的可信度。在此资助期内，我提出的项目的主要目标是：目标1：使用限制在128公里× 128公里区域内的最先进的高分辨率模式，研究驱动极端降水长期变化的环流机制。这样的配置使我们能够更好地控制区域模式的物理输入，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。目的2：比较极端降水事件中旋涡运动（“涡流”）在观测估计和区域气候模式模拟中的空间结构。这样的工作将为模型捕捉与现实世界极端降水相关的大气环流关键特征的能力提供一个关键的测试。目标3：测试环流和降水变化对气候模式参数的敏感性，这些参数近似于被称为“对流上升气流”的小规模垂直运动。当前的全球气候模式难以准确地模拟对流上升气流的影响，而我们的工作将发现模拟极端降水变化的可能后果。目标4：检查云和大气环流之间产生双向相互作用或“耦合”的机制。不同的气候模式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如何在空间中长期变化，对区域降水产生重要影响。这些目标是对区域气候变化模式预估作出革命性改进的重要步骤。我过去在这一领域的工作已经刺激了与加拿大联邦和市政府的接触，并且加拿大国内外的一系列利益相关者（例如政策制定者，结构工程师，农业工业，保险公司）对预测和适应区域气候变化有浓厚的兴趣，将感受到拟议工作的影响。