四川省稻城地区雨滴谱特征研究

Characteristics of Rain Drop Size Distribution in Daocheng of Sichuan Province

利用四川稻城地区2019年5~8月雨滴谱资料,研究不同雨强和不同降水的雨滴谱特征,并提出反射率因子Z、质量加权平均直径D_(m)粒、粒子总数浓度N_(T)、含水量W与雨强R之间的关系,以及Gamma谱形状参数μ和斜率参数Λ之间的关系,并比较了该地区雨滴谱与我国其他地区的差异。结果表明:随着R增大,雨滴谱数浓度、粒径和谱宽也逐渐增大,雨滴谱逐渐变宽、变平坦;对流云雨滴谱明显比层状云宽、数浓度更高,谱型分别呈略微的上凸和下凹;W-R和Z-R幂函数关系最密切,其次为D_(m)-R和N_(T)-R,μ-∧很好符合二项式关系;稻城地区的D_(m)和截距参数Nw与其他区域不同,D_(m)仅大于亚洲季风区江淮流域,而N_(w)仅比华北地区大。

Based on the data obtained in Daocheng, Sichuan Province from May to August, 2019, it studies the difference of DSD under different rain rates and different types of precipitation, explores the relationships among reflectivity Z,mass-weight mean diameter D_(m),total number concentration N_(T),rainwater content W and rain rate R, as well as the relationship between the shape parameter μ and the slope parameter Λ in Gamma distribution, compares the difference of DSD between Daocheng and other areas in China. The results show that with the increase of R, the number concentration, particle size, and spectral width gradually increase, the spectral pattern of DSD gradually becomes wider and flat. The DSD of convective rain is obviously wider and its number concentration is higher than stratiform rain;the two spectra are slightly convex upwards and concave downwards respectively. The power function relationship between W-R and Z-R is the closest, followed by D_(m)-R and N_(T)-R;μ–Λ is in good accord with the binomial relationship. The D_(m) and intercept parameter Nw of Daocheng are different from other areas. Dm is only larger than that in Yangzi-Hwai valley in the Asian monsoon area, while Nw is only larger than that in North China.