基于风廓线雷达、云雷达、粒子谱仪、微波辐射计和自动站等垂直观测设备，结合中尺度数值模式WRF对2017年3月23～24日北京延庆海坨山地区的一次降雪过程进行了观测和数值模拟研究。研究结果表明：垂直探测仪器结合中尺度数值模式可以获得降雪的宏观结构和微物理信息，有助于对降雪的深入研究。此次降雪过程由中高层西南及偏南暖湿气流与低层东南偏冷空气交汇造成动力和水汽辐合抬升形成，4～5 km高度处的风切变有利于降雪的增强。上升气流有助于水汽的输送、冰雪转化以及雪晶凝华、聚合，冰晶数浓度中心对应着上升运动顶部。然而此次降雪云系低层过冷云水含量不足，降雪回波<20 dBZ，回波顶高<7 km，雪花垂直下落速度<2 m s-1，地面降水量大值与低层强回波区对应。降雪粒子谱分布范围较窄，以直径1 mm左右的小粒子为主，相态主要为干雪，基本不存在混合相态。
Snowfall was observed and analyzed by wind profiler radar, cloud radar, disdrometer, microwave radiometer, and automated meteorological readings on 23-24 March 2017 over Yanqing Mountain area in Beijing, combined with the mesoscale numerical model WRF. Results indicated that the vertically-scanning instruments in combination with the mesoscale numerical model obtained a snow macrostructure and microphysical information that can be applied to further snow studies. The snow process was triggered by the intersection of low-level southwesterly warm and moist flow and cold air formed by strong dynamics and moisture convergence, and attendant wind shear at 4-5-km height was conducive to the development and strengthening of the weather system. Updrafts aided in water vapor transmission, as well as ice-snow autoconversion, and deposition and aggregation between snow crystals, while a centered concentration of ice crystals corresponded with the upper boundary of the upward motion. However, in this case, supercooled cloud water at lower layers was insufficient, with an echo of < 20 dBZ, echo top < 7 km, snow vertical velocity < 2 m s-1, and the moment of maximum snowfall corresponding to the lower strong echo area. Snow particle spectrum was narrow, with the majority comprising small particles about 1 mm in diameter. The main phase was dry snow, with a negligible area of mixed precipitation.
黄钰,郭学良,毕凯,周嵬,贾星灿,陈云波,马新成.北京延庆山区降雪云物理特征的垂直观测和数值模拟研究.大气科学,2020,44(2):356~370 HUANG Yu, GUO Xueliang, BI Kai, ZHOU Wei, JIA Xingcan, CHEN Yunbo,MA Xincheng.Vertical Observation and Numerical Simulation of the Clouds Physical Characteristics of Snow-Producing over Yanqing Mountain Area in Beijing.Chinese Journal of Atmospheric Sciences (in Chinese),2020,44(2):356~370复制