山西一次降雪云物理特征的飞机观测研究  

Aircraft-Based Observation of the Physical Characteristics of Snowfall Cloud in Shanxi Province

作　　者：封秋娟 牛生杰[1] 侯团结[4] 范秀平[5] 申东东 杨俊梅 FENG Qiujuan;NIU Shengjie;HOU Tuanjie;FAN Xiuping;SHEN Dongdong;YANG Junmei(College of Atmospheric Physics,Nanjing University of Information Science&Technology,Nanjing 210044;Shanxi Artificial Precipitation Enhancement and Lightning Protection Technical Center,Taiyuan 030032;Key Laboratory for Cloud Physics of China Meteorological Administration,Beijing 100081;Laboratory of Cloud-Precipitation Physics and Severe Storms,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029;Shanxi Meteorological Information Center,Taiyuan 030032)

机构地区：[1]南京信息工程大学大气物理学院,南京210044 [2]山西省人工增雨防雷技术中心,太原030032 [3]中国气象局云雾物理环境重点开发实验室,北京100081 [4]中国科学院大气物理研究所,北京100029 [5]山西省气象信息中心,太原030032

出　　处：《大气科学》2021年第5期1146-1160,共15页Chinese Journal of Atmospheric Sciences

基　　金：国家重点研发计划项目2018YFC1507905、2019YFC1510304;山西省气象局重点项目SXKZDRY20165205;中国气象局云雾物理环境重点开放实验室开放课题2017Z016;江苏省普通高校学术学位研究生科研创新计划项目KYLX16_0938。

摘　　要：通过飞机直接进入降雪云进行探测,并配合MICPAS(气象信息综合分析处理系统)、雷达和卫星等资料,对2011年11月29日山西一次降雪云宏、微观结构特征进行分析。研究发现:本次降雪过程的雷达回波以10~20 dBZ大片层状云回波为主,镶嵌了超过30 dBZ的块状强回波,雷达径向速度零线呈较强的“S”型弯曲,出现“牛眼”结构,从低层到高层有较强的风垂直切变。液态水含量主要位于3.2 km以下,最大值为0.0697 g m^(-3),N_(50)(粒子直径大于50μm的冰雪晶数浓度)、N_(200)(粒子直径大于200μm的冰雪晶数浓度)和冰水含量主要产生于层积混合降雪云的上部,极大值出现在-9.3℃附近,分别为188.4 L^(−1)、33.5 L^(-1)和0.121 g m^(-3)。-14.4℃~-19.7℃冰晶图像以针状、柱状和不规则状为主,以冰晶的凝华增长为主。-9.3℃附近冰雪晶图像以辐枝状、不规则状为主,辐枝状冰晶的聚并碰撞和折裂繁生可能是造成此处冰雪晶高浓度的主要原因。利用指数形式能较好地拟合冰雪晶谱分布,谱拟合参数可以用幂函数N_(os)=1.021λ^(1.684)表示(其中,N_(os)、λ分别表示截距和斜率,N_(os)越大表示小粒子数浓度越大,λ越大表示小粒子数浓度占总粒子数浓度比例越高),相关系数R^(2)为0.86。3.2 km以下存在三次逆温,逆温层的出现使云微物理特征量和拟合参数N_(os)减小,抑制了云内凇附增长和凝华增长,导致本次观测谱拟合参数N_(os)、λ随温度的变化规律与以往的观测不一致,逆温强度越大抑制作用越大。Based on observations from an aircraft that directly entered the snowfall cloud and MICPAS(Meteorological Information Comprehensive Analysis and Processing System),radar and satellite data,the macro and micro structure characteristics of a snowfall cloud in Shanxi Province on 29 November 2011,were analyzed.Notably,the radar echo of this snowfall process was mainly between 10 dBZ and 20 dBZ large stratiform cloud echo,inlaid with more than 30 dBZ massive and strong echo.The zero line of the radar radial velocity had a strong“S”curve with a bull’s eye structure.Strong vertical wind shear was observed from the lower level to the upper level.The liquid water content was mainly below 3.2 km,and the maximum value was 0.0697 g m^(-3).The ice and snow crystal number concentrations N_(50)(Number concentration of ice and snow crystals with particle diameter greater than 50μm)and N_(200)(Number concentration of ice and snow crystals with particle diameter greater than 200μm)and the ice water content were mainly produced in the upper part of the stratiform mixed-phase snowfall cloud,and the maximum values,which were 188.4 L^(-1),33.5 L^(-1),and 0.121 g m^(-3),were obtained at approximately -9.3℃.From -14.4℃ to -19.7℃,the images of ice crystals were mainly needle,columnar,and irregular,and the ice particles grew mainly by deposition.The images of ice and snow crystals at approximately -9.3℃ were mainly dendritic and irregular.The aggregation,collision,and fracture of radial dendritic ice crystals may be the main reason for the high concentration of ice and snow crystals.The distribution of the ice and snow crystal spectra can be well fitted by the exponential form.The spectrum fitting parameters can be expressed by the power function N_(os)=1.021 λ^(1.684)(N_(os) and λ represent intercept and slope,respectively.The larger N_(os) was,the higher the concentration of small particles was.The larger λ was,the higher the proportion of small particle number concentration to total particle number concentration was.

关 键 词：降雪云 冰雪晶图像 形成机制 飞机探测 

分 类 号：P481[天文地球—大气科学及气象学]