青藏高原东部玉树地区雨滴谱特征及云微物理结构分析
Statistical Characteristics of Raindrop Size Distribution and Microphysical Structure of Cloud in Yushu Region of Qinghai Tibet Plateau
中文摘要：
利用青藏高原东部玉树地区的雨滴谱仪和云雷达观测资料，研究了高原东部地区三类云降水微物理特征参量并且拟合出积雨云降水、混合云降水和层状云降水的雨滴谱分布参数，拟合分析参数斜率因子λ与形状因子μ之间的关系。研究不同雷达反射率因子Z和降雨强度R的关系，分析Ka波段云雷达观测下三类降水云的结构特征。得到的结论如下：玉树地区主要降水类型为层状云降水，降雨量小，持续时间短，降雨次数多；三类云降水在玉树地区的Gamma分布拟合模拟较好的粒径在0.562～5.5 mm；利用μ-λ的经验关系分析，层状云雨滴谱浓度分布中小粒径占主要贡献且谱宽最窄，而混合云与积雨云的雨滴谱浓度分布主要贡献粒径分布均匀且谱宽较宽；对三类云降水进行了Z-R关系拟合，B值从积雨云、混合云到层状云是逐渐递减的，有助于参数本地化；云雷达分析降水结构，积雨云和混合云发生发展旺盛，最高云高可达13 km，但混合云降水平均持续时间短于积雨云；层状云发展较为平稳，云高在6～7 km，平均降水持续时间最短。
中文关键词：
雨滴谱，Gamma分布，参数化，玉树地区
KeyWords：
raindrop size distribution, Gamma distribution, parameterization, Yushu region
Abstract：
Based on the data of raindrop spectrometer and Ka-band millimeter wave cloud radar in Yushu area, Eastern Qinghai Tibet Plateau. The microphysical characteristic parameters of three types of cloud precipitation in the eastern plateau are studied, and the raindrop spectrum distribution parameters of cumulonimbus precipitation, stratocumulus precipitation and stratiform cloud precipitation are fitted, and the relationship between the slope factor λ and the shape factor μ is analyzed. The relationship between different radar reflectivity factors Z and rainfall intensity R is studied, and the structural characteristics of three types of precipitation clouds observed by Ka-band millimeter wave cloud radar are analyzed. The conclusions are as follows: the main precipitation type in Yushu area is stratiform cloud precipitation, which has small rainfall, short duration and more rainfall frequency; the Gamma distribution of three types of cloud precipitation in Yushu area is well simulated, and the particle size range is 0.562?5.5 mm; the empirical relationship of μ-λ is used to analyze the distribution of stratiform cloud raindrop spectral concentration, which mainly contributes to the small particle size and the narrowest spectral width, while the mixed precipitation The results show that the distribution of raindrop spectral concentration of cloud and cumulonimbus is mainly contributed by uniform particle size distribution and wide spectral width. Z-R relationship fitting is carried out for the three types of cloud precipitation, and the fitting b value is decreases gradually from cumulonimbus, stratocumulus to stratiform cloud, which is helpful for parameter localization. Cloud radar analysis of precipitation structure shows that cumulonimbus and stratocumulus are developing vigorously, with the highest cloud height up to 13 km, but the stratocumulus precipitation lasts for an average of 12 km The average precipitation duration is the shortest when the cloud height is 6?7 km.