Multiscale Modeling of Cloud Dynamics

云动态的多尺度建模

• 批准号: 1209409
• 负责人: Samuel Stechmann
• 金额: $ 13.75万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1209409&HistoricalAwards=false
• 关键词: Multiscale; Modeling; Cloud; Dynamics

The project investigates the role of turbulence in cloud development and evolution, from an applied and computational mathematics perspective. There is a fundamental challenge to understand multiscale interactions between fine scales and coarse scales in clouds, from cloud droplets and turbulence (micrometers to meters) to turbulent updrafts (meters to kilometers). Both scales are of key importance in determining, for instance, how much solar radiation is reflected by clouds and how much (if any) precipitation is formed. To study these complex interactions, the principal investigator will employ multiscale asymptotic models and stochastic models, building on his previous work with these methodologies. Using multiscale asymptotic models, one of the questions of the project is the effect of the coarse-scale updrafts versus the intermediate-scale fluctuations from cloud pulses and thermals on water transport from low altitudes to higher altitudes. Secondly, using stochastic modeling techniques in addition, the goal is to investigate relationships between aerosol and droplet-size distributions (fine scales) and cloud amount and lifetime (coarse scales). To model these processes across scales from micrometers to kilometers, the principal investigator will use stochastic models to represent the fine-scale interactions between turbulence and droplet evolution, and these fine-scale processes will then be coupled with the coarse-scale deterministic evolution of turbulent cloud updrafts.This project will develop mathematical methods for the modeling of water and energy transport in clouds, which is of fundamental importance in weather prediction, climate science, and air pollution. At present, clouds are a primary source of uncertainty in projections of climate change, since it is still unclear whether increased cloud cover will cool the planet (due to increased reflection of incoming sunlight) or heat it (due to the capacity of clouds to store and redistribute thermal energy). In addition, clouds interact with aerosols and air pollution in various ways, influencing day to day local atmospheric phenomena. For both of these issues, the uncertain role of clouds is determined by the complex interplay of both cloud-scale properties (such as cloud amount and lifetime of a cloud) and smaller-scale properties (such as droplet size distribution and aerosol particles). The project will use modern mathematical techniques to shed light on these questions. Educational activities supported by this project will connect mathematics, cloud physics, and climate science, and they are aimed at high schools with a large percentage of students from underrepresented groups.

该项目从应用和计算数学的角度研究了湍流在云发展和进化中的作用。了解从云滴和湍流（微米到米）到湍流上升气流（米到公里）之间的细尺度和云中的粗尺度之间的多尺度相互作用存在着根本的挑战。这两个量表在确定例如由云反映了多少太阳辐射以及形成多少太阳辐射方面都至关重要。为了研究这些复杂的相互作用，主要研究者将采用多尺度的渐近模型和随机模型，这是基于他先前使用这些方法的工作。使用多尺度模型，该项目的问题之一是粗尺度上升的效果与从云脉冲和水从低海拔到较高高度的水传输中发生的中间尺度波动的效果。其次，使用随机建模技术此外，目标是研究气溶胶和液滴大小分布（细尺度），云量和寿命（粗尺度）之间的关系。 To model these processes across scales from micrometers to kilometers, the principal investigator will use stochastic models to represent the fine-scale interactions between turbulence and droplet evolution, and these fine-scale processes will then be coupled with the coarse-scale deterministic evolution of turbulent cloud updrafts.This project will develop mathematical methods for the modeling of water and energy transport in clouds, which is of fundamental importance in weather prediction,气候科学和空气污染。目前，云是气候变化投影的不确定性的主要来源，因为尚不清楚增加的云覆盖物是否会冷却行星（由于阳光的反射增加）还是加热它（由于云的能力存储和重新分配热能的能力）。此外，云通过各种方式与气溶胶和空气污染相互作用，影响日常的当地大气现象。对于这两个问题，云的不确定作用都取决于云规模属性（例如云和云的寿命）和较小尺度属性（例如液滴尺寸分布和气溶胶粒子）的复杂相互作用。该项目将使用现代数学技术来阐明这些问题。该项目支持的教育活动将连接数学，云物理学和气候科学，它们针对的是来自代表性不足的学生的高中。