Collaborative Research: Characterizing interactions between tropical deep convection and the environment using a buoyancy framework

合作研究：使用浮力框架表征热带深层对流与环境之间的相互作用

• 批准号: 2225956
• 负责人: Fiaz Ahmed
• 金额: $ 16.38万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2225956&HistoricalAwards=false
• 关键词: Collaborative; Research; Characterizing; interactions; between

Tropical convective storms play a significant role in global weather and climate. With current computing technology, it is impossible to directly model all aspects of convection, so scientists rely on parameterizations, which are approximations that are coded into the models. Simulations of Earth’s climate are particularly sensitive to the parameterizations of tropical convection, so it is incumbent on the scientific community to improve understanding of tropical convection to improve the parameterizations that go into weather and climate modeling. In this project, the research team plans to study how tropical convection interacts with its surrounding environment using a new framework that focuses on the entrainment of air near the Earth's surface into the storm. In addition to the potential to improve numerical modeling, the research team will organize a workshop to bring together the tropical convection research community, including a diverse set of early-career scientists and students.The overarching goal of this project is to continue work towards identifying a conceptual model for tropical deep convection that can be used to explain precipitation variability across scales. The research team will build upon the “precipitation-buoyancy (P-B) framework” which relates precipitation and estimates of entraining plume buoyancy. The research team will center their work around two main research questions: (1) to what extent do “grid-scale” O(100 km) integrated measures of convective instability accurately assess the capacity of the atmosphere to support deep convection, and (2) how can we refine grid-scale average instability measures to account for variability and dynamics across scales? The investigators will use new mesoscale convective tracking databases, cold pool gradient feature detection algorithms, long-standing radar data, field campaign data, and satellite observations, combined with novel compositing techniques to address the following objectives:1. Characterize how the precipitation-buoyancy (“P-B”) relationship varies as a function of convective variability across spatial scales. 2. Examine how P-B thresholds change as a function of mesoscale convective system evolution, estimating the sensitivity of deep convection to its thermodynamic environment throughout different lifecycle stages. 3. Characterize how dynamical interactions - mass flux/entrainment, wind shear, vorticity, cold pools - modify thermodynamic controls on deep convective evolution. 4. Apply the refined P-B framework to study diurnal, regional, and intraseasonal precipitation variability across the tropics.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.

热带对流风暴在全球天气和气候中起着重要作用。以目前的计算技术，不可能直接模拟对流的所有方面，因此科学家依赖于参数化，这是编码到模型中的近似值。地球气候的模拟对热带对流的参数化特别敏感，因此科学界有责任提高对热带对流的理解，以改进天气和气候模式的参数化。在这个项目中，研究小组计划使用一个新的框架来研究热带对流如何与周围环境相互作用，该框架将重点放在地球表面附近的空气夹带到风暴中。除了改进数值模拟的潜力之外，研究小组还将组织一个研讨会，将热带对流研究界聚集在一起，包括一组不同的早期职业科学家和学生。该项目的总体目标是继续致力于确定热带深层对流的概念模型，该模型可用于解释跨尺度的降水变化。研究小组将建立在“降水-浮力（P-B）框架”的基础上，该框架将降水与夹带羽流浮力的估计联系起来。研究小组将围绕两个主要研究问题开展工作：(1)“网格尺度”O（100公里）对流不稳定性综合测量在多大程度上能准确评估大气支持深层对流的能力；(2)我们如何改进网格尺度平均不稳定性测量，以解释跨尺度的变异性和动力学？研究人员将使用新的中尺度对流跟踪数据库、冷池梯度特征检测算法、长期雷达数据、野外活动数据和卫星观测，并结合新的合成技术来解决以下目标：描述降水-浮力（“P-B”）关系如何作为对流变率在空间尺度上的函数变化。2. 研究P-B阈值作为中尺度对流系统演化的函数如何变化，估计深层对流在不同生命周期阶段对其热力学环境的敏感性。3. 描述动力学相互作用——质量通量/夹带、风切变、涡度、冷池——如何改变对深层对流演化的热力学控制。4. 应用改进的P-B框架来研究热带地区的日、区域和季节内降水变化。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。