Towards a Better Representation of Cloud-Aerosol Interactions in the Community Earth System Model: With Applications to Heterogeneous Nucleation of Cirrus, and Aerosol-Cloud Intera

在社区地球系统模型中更好地表示云-气溶胶相互作用：在卷云异质成核和气溶胶-云相互作用中的应用

• 批准号: 1640903
• 负责人: Owen Toon
• 金额: $ 60.4万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1640903&HistoricalAwards=false
• 关键词: Towards; Better; Representation; Cloud; Aerosol

Clouds and aerosols play a major role in the Earth's radiative budgets and in the hydrological cycle. It is a challenge problem to realistically represent/simulate clouds and cloud-aerosol interactions in global models of the Earth's climate system because they are very complex and usually much smaller than the typical tens of kilometer sized grid cells in current global models. In order to limit computing costs, the present Community Earth System Model (CESM), which is one of the nation's leading global models, uses a minimalist representation of clouds by computing only their mean particle size and their condensed water mass. These simplifications lead to a vast expansion of tuning parameters whose values are not well defined. As a result, the current CESM cloud model predicts liquid cloud particle sizes that differ greatly from those observed by satellite. The work replaces the CESM liquid cloud model with one that fully tracks the range of particles sizes in the clouds. With full knowledge of the particle sizes much more complete and realistic cloud physics will be implemented in the model, and the number of tunable, poorly defined parameters will be reduced. The new model will also be used to improve the parameterization of physical mechanisms. Another goal of the work is to link aerosols to the ice cloud model, and apply the ice cloud model to determine the role of new ice particle formation, particularly involving organic aerosols, in controlling cloud properties. By utilizing the size resolved liquid and ice models, the study will evaluate the aerosol-cloud climate forcing, one of the most uncertain factors in climate modeling.Cloud properties and aerosol-cloud interactions are among the greatest uncertainties in climate modeling. By improving the physics used to simulate clouds and their interactions with aerosols the uncertainties may be reduced. This project will improve representations of both ice and liquid clouds in CESM, test these changes against data mainly from satellites, and apply the models to well-defined, testable projects involving cloud-aerosol interactions. This project will integrate research and education by advancing discovery and understanding while promoting teaching, training, and learning; broaden participation of underrepresented groups in the Physical Sciences by involving female graduate students; enhance the national infrastructure for research and education by further developing the CESM model; and, provide benefits to society by reducing uncertainty in aerosol radiative climate forcing resulting from a better representation of interactions between clouds and aerosols as well as by improving national tools to address such issues.

云和气溶胶在地球的辐射收支和水文循环中发挥着重要作用。在地球气候系统的全球模式中真实地表示/模拟云和云-气溶胶的相互作用是一个具有挑战性的问题，因为它们非常复杂，通常比当前全球模式中典型的几十公里大小的网格单元要小得多。为了限制计算成本，目前的社区地球系统模型（CESM）是全国领先的全球模型之一，它只计算云的平均粒径和冷凝水质量，使用了一个极简的云表示。这些简化导致调优参数的大量扩展，这些参数的值没有很好地定义。因此，目前的CESM云模型预测的液体云颗粒大小与卫星观测到的大不相同。这项工作取代了CESM液体云模型，取而代之的是一个完全跟踪云中颗粒大小范围的模型。随着粒子大小的充分了解，更完整和真实的云物理将在模型中实现，可调的数量，定义不佳的参数将减少。新模型还将用于改进物理机制的参数化。这项工作的另一个目标是将气溶胶与冰云模型联系起来，并应用冰云模型来确定新冰粒子形成的作用，特别是涉及有机气溶胶，在控制云特性方面的作用。通过利用大小分解的液体和冰模式，该研究将评估气溶胶-云气候强迫，这是气候模式中最不确定的因素之一。云的性质和气溶胶与云的相互作用是气候模式中最大的不确定因素。通过改进用于模拟云及其与气溶胶相互作用的物理方法，可以减少不确定性。该项目将改进CESM中冰云和液态云的表示，根据主要来自卫星的数据测试这些变化，并将模型应用于定义明确、可测试的涉及云-气溶胶相互作用的项目。该项目将整合研究和教育，促进发现和理解，同时促进教学、培训和学习；通过让女性研究生参与，扩大代表性不足群体在物理科学领域的参与；通过进一步发展CESM模式，加强国家研究和教育基础设施；并且，通过更好地反映云和气溶胶之间的相互作用，以及通过改进解决这类问题的国家工具，减少气溶胶辐射气候强迫的不确定性，从而为社会带来益处。

项目成果

An Evaluation of the Representation of Tropical Tropopause Cirrus in the CESM/CARMA Model Using Satellite and Aircraft Observations

利用卫星和飞机观测对 CESM/CARMA 模型中热带对流层顶卷云的表示进行评估

• DOI: 10.1029/2018jd029720
• 发表时间: 2019
• 期刊: Journal of Geophysical Research: Atmospheres
• 作者: Maloney, Christopher;Bardeen, Charles;Toon, Owen Brian;Jensen, Eric;Woods, Sarah;Thornberry, Troy;Pfister, Leonhard;Diskin, Glenn;Bui, Thao Paul
• 通讯作者: Bui, Thao Paul