A Study of Aerosol Effects on Warm Ice Clouds

这项建议的主要目的是研究气溶胶对暖冰云的影响。这些云是混合相云，包含冰粒和过冷液滴，可以在0 ℃和-40 ℃之间发生。云是由冰还是液体组成，对于确定它将多少来自太阳的辐射反射回太空至关重要，因此对于气候预测至关重要。PI感兴趣的是如何灰尘气溶胶和烟雾从生物质燃烧或其他人为气溶胶作为冰核影响这些云的微物理和辐射特性，以及在何种程度上改变降水形成过程。为了实现这一目标，气溶胶模式已与美国国家大气研究中心（NCAR）的大气环流模式（GCM），社区大气模式（CAM）。作为PI目前研究的一部分，她在NCAR CAM中实现了冰晶混合比和数量浓度预报方程，以研究气溶胶卷云气候效应，基于灰尘，烟尘和硫气溶胶对这些冷云的影响的新参数化。这项研究将扩展这一参数化处理沉积成核和接触成核在温暖的冰云（T-40 C）。在即将进行的云中冰实验（ICE）期间开发的数据将用于指导参数化的开发。将使用具有尺寸分辨微物理学的云块模型来模拟ICE期间的条件并开发冰成核参数化。这一参数化将被包括在CAM模式的冰相微物理过程。CAM与IMPACT气溶胶模型相结合，将用于模拟当今和工业化前的气候，以评估人为气溶胶的影响。PI还将研究观察到的尘埃浓度趋势的可能性及其对冰云和气候的影响。来自卫星和激光雷达观测的可用数据将用于评估她的结果。除了上述项目外，PI计划继续与欧洲的量化项目合作。Quantify是第六框架方案下的一个欧洲资助的项目，有40个合作伙伴和8个单独的工作包。QUANTIFY的主要目标是量化全球和欧洲交通系统对当前情况和未来发展的几种情景的气候影响。PI在Quantify中的主要工作是将其耦合气溶胶/气候模型（IMPACT模型与NCAR CAM模型耦合）的预测与冰微物理学的预测与丹麦气象研究所的云解析模型的预测进行比较。这个项目的智力价值在于它有助于了解尘埃和人为冰核在对气候的间接影响中可能发挥的作用。该项目更广泛的价值在于它对科学的贡献，这对政策决策是有用的。此外，研究生将参与研究，使本项目将有助于研究生培养。此外，在2007年3月，彭纳将在密歇根州教授“云和降水”课程。计划在这段时间内进行的ICE实验的真实的时间数据将用于期末项目，以使学生熟悉现场实验在理解冰成核现象中的作用。

The main objective of this proposal is to study aerosol effects on warm ice clouds. These are mixed-phase clouds that contain both ice particles and supercooled liquid droplets, and can occur between 0C and -40C. Whether a cloud is composed of ice or liquid is crucial for determining how much of the incoming radiation from the sun it reflects back to space and therefore crucial for climate prediction. The PI is interested in how dust aerosols and smoke from biomass burning or other anthropogenic aerosols acting as ice nuclei influence the microphysical and radiative properties of these clouds as well as the extent to which precipitation formation processes are altered. To achieve this goal an aerosol model has been coupled with the National Center for Atmospheric Research (NCAR) General Circulation Model (GCM), Community Atmospheric Model (CAM). As part of the PI's present research, she has implemented ice crystal mixing ratio and number concentration prognostic equations in the NCAR CAM in order to study aerosol-cirrus-climate effects, based on a new parameterization for the effects of dust, soot, and sulfur aerosols on these cold clouds. This study will extend this parameterization to treat deposition nucleation and contact nucleation in warm ice clouds (T -40C). Data developed during the forthcoming Ice in Clouds Experiments (ICE) will be used to guide the development of the parameterization. A cloud parcel model with size-resolved microphysics will be used to both simulate conditions during ICE and to develop the ice nucleation parameterization. This parameterization will then be included in the ice phase microphysical processes in the CAM model. CAM coupled to the IMPACT aerosol model will be used for simulations for the present-day and pre-industrial climate to assess the effects of anthropogenic aerosols. The PI will also examine the possibility of trends observed in dust concentration and their effect on ice clouds and climate. Available data from satellite and lidar observations will be used to evaluate her results.In addition to the project outlined above, the PI plans to continue her collaboration in the European-based Quantify Project. Quantify is a European-funded project under the Sixth Framework Programme with 40 partners and 8 separate work packages. The main goal of QUANTIFY is to quantify the climate impact of global and European transport systems for the present situation and for several scenarios of future development. The PI's main effort in Quantify will be to compare the predictions of her coupled aerosol/climate model (the IMPACT model coupled to the NCAR CAM model) with ice microphysics to the predictions of a cloud-resolving model from the Danish Meteorological Institute. The intellectual merit of this project lays in its contribution to an understanding of the possible role of both dust and anthropogenic ice nuclei in indirect effects on climate. The broader merits of the project lie in its contribution to the science that is useful for policy decisions. Moreover, graduate students will participate in the research, so that this project will contribute to graduate training. Additionally, during March 2007, Penner will be teaching the "clouds and precipitation" course at Michigan. Real time data from the ICE experiments planned for this time frame will be used in an end-of-term project to acquaint students with the role of field experiments in understanding ice nucleation phenomena.