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

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-气溶胶相互作用是一个具有挑战性的问题，因为它们非常复杂，并且通常比当前全球模式中典型的数十公里大小的网格单元小得多。 为了限制计算成本，目前的社区地球系统模型（CESM），这是美国领先的全球模型之一，使用云的最低限度的表示，只计算其平均颗粒大小和冷凝水的质量。 这些简化导致了调谐参数的大量扩展，这些参数的值没有很好地定义。 因此，目前的CESM云模型预测的液态云颗粒大小与卫星观测到的有很大差异。 这项工作取代了CESM液体云模型，完全跟踪云中颗粒大小的范围。 在充分了解颗粒大小的情况下，将在模型中实现更完整和更真实的云物理学，并且将减少可调的、定义不明确的参数的数量。 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的冰粒形成的作用，特别是涉及有机气溶胶，在控制云的性质。 利用尺度分辨的液体和冰模式，本研究将评估气溶胶-云气候强迫，这是气候模拟中最不确定的因素之一，云的特性和气溶胶-云相互作用是气候模拟中最大的不确定性之一。 通过改进用于模拟云及其与气溶胶相互作用的物理学，可以减少不确定性。 该项目将改进CESM中冰云和液云的表示，根据主要来自卫星的数据测试这些变化，并将模型应用于涉及云-气溶胶相互作用的定义明确的可测试项目。 该项目将通过促进发现和理解，同时促进教学、培训和学习，将研究与教育结合起来;通过让女研究生参与，扩大代表性不足群体对自然科学的参与;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，在本发明中，通过更好地反映云和气溶胶之间的相互作用，减少气溶胶辐射气候强迫的不确定性，以及通过改进国家工具，为社会带来惠益来解决这些问题。

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.