摘要
鉴于目前云数值模式和中尺度数值模式中云和降水过程大多用体积水参数化的方式描述,而不同模式所用的粒子谱不同或粒子谱的参数不同,用这些模式模拟研究云和降水的物理过程、降水形成机制、催化防雹和催化增雨机理以及预报降水等就遇到这样一个问题:粒子谱或谱参数不同对研究结果有何影响?因此利用中国科学院大气物理研究所的三维冰雹云催化数值模式,做雹云中粒子谱参数变化的数值试验,分析了冰雹云中雨滴谱、冰晶谱、霰谱的形状参数对降雨降雹、云中微物理过程的影响。结果表明,雨滴谱形状参数变化,对降雨形成机制基本没有影响,对与雨滴有关的物理过程有直接影响。霰谱对地面降雹量、降雹强度、雨强的影响较大,对降雨量影响较小;对冰晶、霰以及冰雹的质量和数量产生率都有明显的影响,云中的所有微物理过程均受到了不同程度的影响,对有些过程影响最为显著,它不但影响粒子的产生过程,也影响粒子的增长过程。冰晶谱对降水量的影响较小,但对各种粒子的某些形成或增长过程影响较大,有的很大。此外,冰晶谱型的变化,对不同地区云或不同个体云降水的影响程度不同,反映了滴谱谱型对云和降水影响的复杂性。利用这些研究结果,讨论了云模式的使用问题。
At present, parameterization methods to describe cloud and precipitation processes are widely used in cloud models and mesoscale models, but drop size distributions in different models are different and parameters in the drop size distributions also different. When studying precipitation formation mechanism, weather modification technique, and mechanism of hail suppression with seeding by using those models, we will encounter a problem, what is the influence of different drop size distributions and parameters on cloud and precipitation simulated？ Therefore, using the 3-D hail cloud numerical model developed by the Institute of Atmospheric physics, CAS, we performed numerical experimentations of the parameter variation of the drop size distribution in two hailstorms and analyzed the influence of shape parameters of raindrop, ice crystal, graupel size distributions （a r, ai, a g） on rainfall, hail amount, and microphysical processes. The results show that the ar variation had no effect on precipitation formation mechanism on the whole and has direct effect on physical processes relating with raindrop, while indirect effect is even more distinct. When ar varies with height, the effect on hail amount is substantial. The ag variation has a slight effect on rainfall, but has a significant effect on hail amount, hailrate, and rainrate. The ag variation has obvious effect on generating rate of the number and mass of ice crystal, graupel, and hail, and also the effect of various degrees on the all microphysical processes in cloud. The ag variation has effect not only on the generating processes of particles hut also on the growing processes of particles in cloud. When ar varies, the effects on some generating and growing processes of all particles in cloud are obvious, and some of them are very distinct. Besides, the a i variation in different clouds located in different places （Nanjing and Xunyi cases） has different effects on precipitation, reflecting the complexity of the impact of drop size distribution shape on cloud and precipitation. At last, based on the above research outcomes, we also discuss problems about using cloud model.
出处
《气象学报》
CAS
CSCD
北大核心
2007年第2期221-230,共10页
Acta Meteorologica Sinica
基金
国家自然科学基金项目(40475006)
关键词
粒子谱
云模拟
谱影响
Drop size distribution, Cloud simulation, Influence of drop size distribution.
