基于微雨雷达的六盘山区地形云降水宏微观特征观测分析  

Observation and analysis on the macroscopic and microcosmic characteristics of topography, cloud and precipitation in Liupan Mountain area based on micro rain radar

作　　者：曹宁 张立新[1] 桑建人[2,3] 姚展予[4] 马宁[2,3] 田磊[2,3] CAO Ning;ZHANG Lixin;SANG Jianren;YAO Zhanyu;MA Ning;TIAN Lei(Nanjing University of Information Science&Technology,Nanjing 210044,China;Key Laboratory for Meteorological Disaster Monitoring and Early Warning and Risk Management of Characteristic Agriculture in Arid Regions,Yinchuan 750002,China;Ningxia Key Laboratory of Meteorological Disaster Prevention and Reduction,Yinchuan 750002,China;Chinese Academy of Meteorological Sciences,Beijing 100081,China)

机构地区：[1]南京信息工程大学,南京210044 [2]中国气象局旱区特色农业气象灾害监测预警与风险管理重点实验室,银川750002 [3]宁夏气象防灾减灾重点实验室,银川750002 [4]中国气象科学研究院,北京100081

出　　处：《气象科学》2019年第6期775-785,共11页Journal of the Meteorological Sciences

基　　金：国家自然科学基金面上项目(41775139);宁夏回族自治区重点研发计划项目(2019BEG03001);宁夏自然基金(NZ1732)

摘　　要：利用2017年6—11月宁夏六盘山区收集的微雨雷达和微波辐射计等探测资料,对比分析了六盘山区山脊和山谷对流云降水、层状云和浅积云降水过程中的云微物理特征及亮带,针对典型层状云降水事件山脊和山谷站的亮带及以下各层的雨滴谱分布特征,探索了亮带以上几层水凝物的分类。结果发现:六盘山区三类降水云山脊的反射率及反射率衰减程度均高于山谷,表明地形强迫使得山脊降水云的物理和动力过程较山谷更剧烈,层状云降水过程中山脊0℃等温线以上的反射率明显高于山谷,表明山脊在0℃等温线以上有更多水凝物。分析一次典型层状云降水过程发现:六盘山区降水液滴自亮带下落的过程中,碰并过程占主导;亮带以下各层DSD符合Gamma分布,山脊站Gamma分布的相关性比山谷站强且拟合优度更优;降水开始的前3 min,推测-4~0℃等温线之间的水凝物主要是霰,此后水凝物主要是雪颗粒和霰,而山谷在降水开始的前5 min,-4~0℃等温线层之间的水凝物主要是雪颗粒和较大的霰,此后水凝物主要是霰。Detection data,from the Micro Rain Radar(MRR-2)and microwave radiometer situated in Liupan Mountain area,southern Ningxia Hui Autonomous Region,China,were used to explore the cloud microphysical and Bright Band(BB)characteristics of convective cloud,stratiform cloud and shallow cloud precipitation in ridge and valley in Liupan Mountain area.According to the distribution characteristics of raindrop spectrum in the bright zone of mountain ridges and valleys and the layers below the bright zone in typical stratiform cloud precipitation events,the classification of hydraulic condensate in the layers above the bright zone were explored.The results showed that the reflectivity and reflectivity attenuation of three kinds of precipitation clouds in Liupan Mountain ridges were higher than those in valleys,indicating that terrain forcing made the physical and dynamic processes of precipitation clouds on ridges more intense than those in valleys.The reflectivity above the isotherm of 0℃of the ridges was obviously higher than that of the valleys in the process of stratiform cloud precipitation,which indicated that there were more hydrates in the ridge above the isotherm of 0℃.Specifically,a stratiform precipitation event that occurred in 28 July 2017 featured a BB was studied.It was found that during the event,the Drop Size Distribustion(DSD)in each layer below the BB conformed to the Gamma distribution,the correlation of Gamma distribution of the ridge stations was better than that of the valley stations of the Liupan Mountain area.Meanwhile,according to the falling velocity characteristics of various hydrometeors,this paper attempted to classify the hydrometeors in each layer between-4℃and 0℃isotherms above the BB.It was found that at the beginning of the precipitation event,the graupel was dominant at the ridge stations,and the main hydrometeors were snow particles and graupel then after,while the snow particles and large graupel were dominant at the beginning of the precipitation event at the valley stations,and

关 键 词：六盘山区 微雨雷达 亮带 DSD 伽马分布 

分 类 号：P407.7[天文地球—大气科学及气象学]