黄山层状云和对流云降水不同高度的雨滴谱统计特征分析

根据2011年6~7月在黄山不同高度采用PARSIVEL雨滴谱仪测得的雨滴谱数据，对不同海拔高度上两类（层状云和对流云）降水粒子谱的微物理特征量、Gamma函数拟合以及雨滴的下落速度进行对比分析，结果表明:对流云降水的雨水含量和降水强度、雨滴的各类尺度参数和数浓度都比相同位置上层状云降水的大，同类降水中，山腰的雨滴尺度大于山顶和山底，这可能与各观测点和云底相对位置的不同有关；随降水强度增加，雨滴的质量加权平均直径D_m逐渐增大，广义截距参数（log₁₀N_w）的标准差逐渐减小。拟合结果表明各高度的雨滴谱都比较符合Gamma分布，由拟合参数分析雨滴谱的演变，发现相对于对流云降水，层状云降水粒子谱随高度的变化较小，雨滴谱的演变较为稳定。此外，本文还对两类降水中雨滴的下落速度及影响落速的因素进行了分析。

Statistical Characteristics of Raindrop Size Distribution for Stratiform and Convective Precipitation at Different Altitudes in Mt. Huangshan

Based on the raindrop size distribution (RSD) data observed with PARSIVEL disdrometers deployed at different altitudes on Mt. Huang from June to July 2011, several microphysical parameters and the Gamma function fitting to raindrop spectra as well as the falling velocity of raindrops at different altitudes for different rain types (stratiform and convective) were compared and analyzed. Results show that convective precipitation had higher rainwater content, more intense rainfall rate, larger raindrops and higher raindrop concentrations compared with the stratiform precipitation at the same height; for both convective and stratiform precipitation, the diameter of raindrops on the mountainside was larger than that in the mountaintop and mountain bottom, which is possibly related to the difference in observation positions relative to the cloud bases. With increasing rain rate, the mass-weighted mean diameter (D_m) of raindrops increased and the standard deviation of generalized intercept parameter (log₁₀N_w) decreased. The RSDs from all sampling positions were in good agreement with the gamma distribution. The evolution of raindrop spectrum was then investigated using three fitting parameters. It was found that compared with RSDs for convective precipitation, the RSDs for stratiform precipitation showed smaller variation between different altitudes, which suggests that its evolution was more stable. Finally, the raindrop falling velocity and its influential factors were studied.