Collaborative Research: Examining Cloud-Radiation Feedback at Convective Scales in Tropical Cyclones

合作研究：检查热带气旋对流尺度的云辐射反馈

• 批准号: 2331120
• 负责人: James Ruppert
• 金额: $ 43.86万
• 依托单位: University of Oklahoma Norman Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-11-01 至 2026-10-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2331120&HistoricalAwards=false
• 关键词: Collaborative; Research; Examining; Cloud; Radiation

The overarching goal of this research is to expand our understanding of how tropical cyclones (e.g., hurricanes and typhoons) form and intensify. Tropical cyclones are the leading driver of losses to life and property in the US, with coastal population growth and climate change exacerbating these impacts. However, many gaps remain in understanding their formation and intensification, despite decades of study. This project therefore addresses an issue that only grows more pressing with time. The investigators will examine the interaction between clouds and radiation. Recent work reveals that this interaction accelerates the formation of tropical cyclones. This project will advance our understanding of this feedback at the scales of individual thunderstorm systems. By doing so, this research will ultimately help improve the forecasting of tropical cyclones, which will in turn help mitigate losses of life and property when they make landfall. The project will also directly support the leadership and professional development of early-career scientists, graduate researchers, and undergraduate researchers. In support of advancing STEM education, the project team will conduct K-12 educational outreach through “Skype a Scientist” and other virtual activities.To address science gaps related to cloud–radiation feedback in tropical cyclones (TCs), this research will address the following questions:1. What are the responses of buoyancy, vertical motion, and moist entropy to cloud–radiation forcing (CRF) on convective scales in tropical shallow convection, deep convection, and stratiform rainfall?2. What are the unique roles of radiative feedback in these regimes in accelerating convective upscale development and TC genesis, and through what mechanism(s) do they do so?3. How robust are simulated convective-scale responses to CRF to changes in model framework, physical parameterization, and grid resolution?These questions will be addressed through a series of novel, process-oriented numerical model experiments using both regional and global convection-permitting modeling. Following a hypothesis-driven approach, model experiments will be executed to examine the transient response of clouds and deep convection (i.e., on time scales down to ~1 hour and less) to the removal and switch-on of cloud–radiative forcing (CRF). A novel aspect of the experiments is the selective inclusion/exclusion of CRF in specific populations of clouds and precipitation. This approach is motivated by the novel hypothesis that CRF in stratiform rain and anvil clouds plays a leading role in accelerating TC genesis. These experiments will be cast in both realistic and idealized frameworks to support both robustness and representativeness. The project will also entail studying model uncertainty tied to the numerical representation of hydrometeors and radiative forcing in distinct cloud populations, being among the first to examine and document this sensitivity at convective scales in the context of TC genesis. The results of this project are therefore expected to support the advancement of model prediction and forecasting across a broad range of scales and settings. Since CRF is recognized to be an important physical process on a wide range of physical scales, the new lessons arising from this work are expected to apply more broadly than the TC subject.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

这项研究的首要目标是加深我们对热带气旋（例如飓风和台风）如何形成和加强的了解。随着沿海人口增长和气候变化的加剧，热带气旋是造成美国生命和财产损失的主要因素。然而，尽管经过数十年的研究，研究人员将研究云与云之间的相互作用，但在理解它们的形成和强化方面仍然存在许多差距。最近的工作表明，这种相互作用加速了热带气旋的形成，该项目将增进我们对单个雷暴系统规模的反馈的理解，最终将有助于改进热带气旋的预报。反过来，该项目还将直接支持早期职业科学家、研究生研究人员和本科生研究人员的领导力和专业发展，以支持推进 STEM 教育。 K-12 教育外展通过“Skype a Scientist”和其他虚拟活动。为了解决与热带气旋 (TC) 云辐射反馈相关的科学差距，本研究将解决以下问题：1. 浮力、垂直运动和湿熵的响应是什么？热带浅对流、深层对流和层状降雨对流尺度上的云辐射强迫（CRF）有何影响？2．对流高档发展和 TC 成因，以及它们通过什么机制做到这一点？ 3. 模拟的对流尺度对 CRF 对模型框架、物理参数化和网格分辨率变化的响应有多鲁棒？一系列新颖的、面向过程的数值模型实验，使用区域和全球对流允许模型，遵循假设驱动的方法，将执行模型实验来检查云和深层对流的瞬态响应（即准时）。该实验的一个新颖之处是在特定的云和降水群中选择性地包含/排除 CRF。受层状雨和砧云中的 CRF 在加速 TC 生成中发挥主导作用的新假设的启发，这些实验将在现实和理想化的框架中进行，以支持鲁棒性和代表性。该项目还需要研究模型的不确定性。不同云群中水汽凝结和辐射强迫的数值表示，是第一个在 TC 成因背景下检查和记录对流尺度这种敏感性的项目之一。因此，该项目的结果预计将支持模型预测和发展的进展。由于 CRF 被认为是广泛物理尺度上的重要物理过程，因此这项工作产生的新经验预计将比 TC 主题更广泛地应用。该奖项反映了 NSF 的成就。法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。