利用耦合了新的暖云参数化方案的中尺度模式(MM5),研究了暖云降水中巨核的作用.在这个暖云方案里,先假定一个三模态的气溶胶正态对数分布,然后考虑对流、扩散、云滴和雨滴的核化(非核化)过程,再由气溶胶质量的预报量显式地计算出气溶胶的数浓度.选择了华北地区2005年6月25～26日的一次弱冷锋过程,并以此研究了巨核对云和降水的影响.研究表明,巨核具有增强雨滴的凝结、碰并和云雨自动转化过程的作用,使得云滴数减少高达40％,云水减少达20％,云滴有效半径增加高达30％左右.在污染和清洁环境下巨核均可增加降水.%A warm cloud microphysical parameterization was incorporated into a regional model to study the sensitivity of cloud-radiative properties and precipitation to aerosols. Assuming a tri-modal lognormal aerosol size distribution, the aerosol numbers are explicitly calculated from prognostic aerosol masses, considering advection, diffusion, and cloud and rain drop activation/deactivation processes. Sensitivity experiments of a cold front passing through northern China during 25 - 27 June 2005 with different initial conditions for clean, continental, and urban types of aerosols were then conducted to study the Giant Cloud Condensation Nuclei (GCCN)'s effects. It is found that the presence of giant nuclei enhances the condensation, collection, and cloud-rain auto-conversion process, leading to the decrease of cloud drop numbers and cloud water by 40% and 20% respectively, to the increases of cloud drop radius by 30%, and increases accumulated precipitation both in polluted and clean environment.
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