基于卫星观测的中国人为气溶胶对冰云和混合相云及其降水影响的研究

Aerosol indirect effect on ice and mixed-phase clouds is one of the largest uncertainties in global radiative forcing from pre-industrial time to the present. Anthropogenic aerosols could serve as ice nucleating particles. The anthropogenic aerosol loadings in China can range from small to extremely large values. Accurate estimation of the potential impacts of anthropogenic aerosols on ice and mixed-phase clouds and associated precipitation is the key issue for reducing uncertainty of the aerosol indirect effect. However, to the best of our knowledge, very few observational studies have investigated or compared the impact of various anthropogenic aerosol types on the physical properties of different ice and mixed-phase cloud types. Therefore, in this study, we will establish a dataset for various anthropogenic aerosol types and different ice and mixed-phase cloud types with high spatio-temporal resolution in China based on A-Train satellite observations. Based on this dataset, we will investigate the potential impacts of anthropogenic aerosols on ice and mixed-phase clouds and associated precipitation systemically, discuss the impact of meteorological conditions on the observed aerosol-cloud relationship, and extract the “real” effect of anthropogenic aerosols on ice and mixed-phase clouds. This proposed study will not only enable us to reduce the uncertainty of the aerosol indirect effect for providing better aerosol-cloud interaction parameterization scheme for climate models, but also enhance our level of understanding of aerosol-cloud-climate interaction.

气溶胶-冰云、混合相云的间接效应是辐射强迫中重要的不确定性来源，而人为气溶胶充当冰核的能力却经常被忽略。中国人为气溶胶浓度变化范围大，准确估算人为气溶胶对冰云、混合相云及其降水的影响是减小气溶胶间接效应不确定性的基础和关键，但目前开展人为气溶胶对不同类型的冰云、混合相云的影响的研究工作相对较少。为此，本项目拟针对中国人为气溶胶对不同类型冰云、混合相云的影响这一科学问题，基于A-Train卫星观测，建立高时空分辨率的不同类型气溶胶和冰云、混合相云的资料库，较为全面地分析中国人为气溶胶对不同类型冰云、混合相云性质及其降水的影响。在此基础上，探讨气象条件对人为气溶胶-冰云、混合相云关系的影响。本项目的研究成果对减小中国气溶胶间接效应的不确定性，为气候模式的气溶胶-云过程提供更好的参数化方案，提高气溶胶-云-气候相互作用的认识水平具有重要的科学意义。

气溶胶-冰云的相互作用是辐射强迫中重要的不确定性来源之一，同时，人为气溶胶已经被证实能够充当冰核，但我国人为气溶胶与冰云的相互作用的研究相对较少，开展我国人为气溶胶和冰云的相互关系的研究有助于减小我国气溶胶间接效应的不确定性，为气候模式的气溶胶-云过程提供更好的本地参数化方案，提高气溶胶-云-气候相互作用的认识水平。本项目基于A-Train卫星观测，建立了高时空分辨率的不同类型气溶胶和冰云的资料库，分析了我国人为气溶胶与冰晶有效半径、冰云厚度、冰水路径等冰云关键性质的关系，探讨了包括相对湿度、风速、对流有效位能等气象条件对上述关系的影响，研究结果表明：我国人为气溶胶和冰云性质之间存在关系，这种关系随人为气溶胶光学厚度而变化，同时受到气象条件的调控。在完成了预定任务的基础上，本项目还开展了气候变化和我国云量、降水、气溶胶污染的相关研究，揭示了全球变暖对我国云和降水的变化有重要影响，我国汾渭平原冬季霾日年际变率受到EU模态的影响，广东地区冬季霾日受到IOD和ENSO的协同调控。