目前大气环流模式对层云和对流过程中混合云冰晶异质核化过程的模拟存在很大的不足。其中，清华大学地学中心的FDAM和中国科学院大气物理研究所的GMAIL大气环流模式在层云过程中采用的混合云冰晶异质核化方案是Meyers et al.(1992)，该方案仅是基于观测资料经验拟合得到核化冰晶数浓度和温度的关系，并没有考虑气溶胶的影响。同时，这两个大气环流模式在积云对流中采用的参数化方案是没有微物理版本的Zhang-McFarlane方案，因此混合云的冰晶异质核化过程是完全未在积云对流中考虑的。本项目申请以Wang et al.(2014a,b)发展的基于经典冰晶异质核化理论的沙尘和黑碳冰晶异质核化参数化方案为基础，进一步考虑冰晶核化过程及其对气溶胶的清除效应。该参数化方案改进后，将接入中国这两个大气环流模式中，改进模式层云和对流中混合云冰晶异质核化过程。之后，项目将评估新方案对东亚降水影响。

In global climate models (GCMs), it is a great challenge to parameterize the heterogeneous ice nucleation in mixed-phase stratiform and convective clouds. Among these GCMs, FDAM of Center for Earth System Science (CESS) of Tsinghua University and the Grid-point Atmospheric Model of IAP LASG (GAMIL) parameterized the heterogeneous ice nucleation in mixed-phase stratiform clouds following Meyers et al. (1992). This scheme predicts the nucleated ice number concentrations based an empirical relationship, only linking to temperature without considering the role of aerosols. For deep convection, these two models both utilize the version of Zhang-McFarlane scheme without considering microphysics. Therefore, the heterogeneous ice nucleation in convection is totally neglected. The main objective of this proposal is to develop a heterogeneous ice nucleation scheme used in both stratiform and convective clouds in FDAM and GAMIL. This new heterogeneous ice nucleation scheme is based on a classical-nucleation-theory (CNT) parameterization developed by Wang et al. (2014a, b), but with an improvement of taking ice nuclei scavenging into account in this proposal. Since the nucleated ice number concentrations predicted by the heterogeneous ice nucleation will affect precipitation from the mixed-phase clouds, its impacts on East Asia (large amounts of mixed-phase clouds exist) precipitation will be mainly studied.