AGS-PRF: Modeling Ice Crystal Habit Evolution from Vapor Growth and Riming--Investigating How Evolving Ice Particle Properties Impacts Clouds, Precipitation, and Phase Partitioning

AGS-PRF：模拟蒸汽生长和沸腾的冰晶习性演化——研究演化的冰粒特性如何影响云、降水和相分配

• 批准号: 1524267
• 负责人: Anders Jensen
• 金额: $ 8.6万
• 依托单位: Jensen Anders
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1524267&HistoricalAwards=false
• 关键词: AGS; PRF; Modeling; Ice; Crystal

Representing ice in microphysics models is important not only to study the effects of ice on cloud dynamics and cloud lifetime, but also for accurate quantitative precipitation forecasts. Traditional microphysics parameterizations artificially separate ice into categories such as cloud ice, snow, and graupel. These models assume that for each category ice crystal size varies with mass, but they do not account for ice crystal shape evolution. In nature, ice crystal shape, or habit, is temperature dependent and evolves as ice moves through a cloud. Ice crystal shape significantly affects vapor growth rates by varying the gradients in the encompassing vapor field. Ice crystal shape also influences riming rates and fall speed. Traditional models are not able to capture this ice crystal shape sensitivity.This project will study the impact of ice crystal shape evolution on different cloud systems. Simulations will be conducted using the Weather Research and Forecasting (WRF) model to look at how ice crystal habit evolution impacts orographic precipitation, tropical cyclone dynamics and precipitation, and squall lines. A 2-dimensional modeling framework will also be used to explore the effects of evolving ice crystal shape on phase partitioning in mixed-phase clouds. Finally, how representing lightly-rimed ice crystals, which is now possible by evolving ice crystal shape, impacts mixed-phase cloud stability will be studied. Intellectual Merit:The research provides a unique opportunity to study how ice crystal habit evolution impacts different cloud systems. At present, the degree to which ice particle shape evolution influences cloud evolution is unknown. With the new microphysics parameterization, the influence evolving ice crystal shape has on cloud system properties can be explored. How light riming affects mixed-phase clouds can also be examined for the first time.Broader Impacts:Modeling ice crystal fall speed evolution which is partially determined by ice crystal shape is crucial for quantitative precipitation forecasts. Also, cirrus cloud properties and lifetime are incredibly sensitive to ice crystal fall speeds. Cirrus cloud radiative properties depend on ice crystal shape as well, meaning ice crystal shape could have important influences on climate. Because the microphysical methods in this study can, in principle, be used in any modeling framework, the research has the potential to impact modeling ranging from operational forecasting through climate studies of ice clouds. Being able to more accurately forecast precipitation, especially heavy or persistent precipitation that could cause flooding in general makes this research relevant to society.

在微物理模型中代表冰不仅对研究冰对云动力学和云寿命的影响至关重要，而且对于准确的定量沉淀预测也很重要。 传统的微物理参数化将冰人为地分为云层，雪和graupel等类别。这些模型假设每个类别的冰晶大小都随质量而变化，但它们不解释冰晶形状的演化。在自然界中，冰晶形状或习惯取决于温度，并且随着冰通过云而发展。 冰晶形状通过改变包含蒸气场的梯度来显着影响蒸气的生长速率。冰晶形状还会影响重晶率和降速。 传统模型无法捕获这种冰晶形状的敏感性。该项目将研究冰晶形状演化对不同云系统的影响。 将使用天气研究和预测（WRF）模型进行仿真，以研究冰晶习惯的进化如何影响地式降水，热带气旋动力学和降水以及挤压线。 二维建模框架还将用于探索不断发展的冰晶形状对混合相云中相分配的影响。 最后，将研究如何通过不断发展的冰晶形状来代表浅冰晶体，从而影响混合相云的稳定性。 智力优点：这项研究提供了一个独特的机会来研究冰晶习惯如何影响不同的云系统。 目前，冰颗粒形状进化影响云进化的程度尚不清楚。有了新的微物理参数化，可以探索影响冰晶形状对云系统特性的影响。 光线如何影响混合相云的方式也可以首次检查。Broader的影响：建模冰晶体降速速度的演化部分由冰晶形状确定，对于定量沉淀预测至关重要。 同样，卷云的特性和生命周期对冰晶跌落速度非常敏感。卷云辐射特性也取决于冰晶体的形状，这意味着冰晶形状可能会对气候产生重要影响。 由于本研究中的微物理方法原则上可以在任何建模框架中使用，因此该研究可能会影响建模，从运营预测到冰云的气候研究。 能够更准确地预测降水量，尤其是沉重或持续的降水，这通常会导致洪水泛滥，从而使这项研究与社会有关。