CAJ | 학술논문

联合利用3 GHz双偏振雷达RHI探测数据和温度廓线数据,建立了云粒子相态反演的模糊逻辑算法,算法采用Beta型成员函数,成员变量包括:水平反射率因子、线性退偏比,差分反射率及温度0℃,-40℃对应高度,反演出的相态包括毛毛雨、雨、低密度干冰晶、高密度十冰晶、湿冰晶、十霰、湿霰、小冰雹、大冰雹、雨夹雪和液态云滴等11种,并利用雷达的连续探测数据对一次层状云降水过程中水凝物相态的演变情况进行了分析,得到如下结果:初始阶段层状云相态呈现分层结构,从上至下依次为高密度干冰晶、湿冰品和液态云滴;初始阶段云体中的同波大值区核心区域为大的冰相粒子,其余部分为液态粒子;在初始到成熟阶段演变中,回波大值区上部液态粒子逐步向冰相转化;消散阶段云中零度层亮带逐步消失,零度层以上云粒子结构呈现高密度干冰品包裹湿冰品的情况.
연합이용3 GHz쌍편진뢰체RHI탐측수거화온도곽선수거,건립료운입자상태반연적모호라집산법,산법채용Beta형성원함수,성원변량포괄:수평반사솔인자、선성퇴편비,차분반사솔급온도0℃,-40℃대응고도,반연출적상태포괄모모우、우、저밀도간빙정、고밀도십빙정、습빙정、십산、습산、소빙박、대빙박、우협설화액태운적등11충,병이용뢰체적련속탐측수거대일차층상운강수과정중수응물상태적연변정황진행료분석,득도여하결과:초시계단층상운상태정현분층결구,종상지하의차위고밀도간빙정、습빙품화액태운적;초시계단운체중적동파대치구핵심구역위대적빙상입자,기여부분위액태입자;재초시도성숙계단연변중,회파대치구상부액태입자축보향빙상전화;소산계단운중령도층량대축보소실,령도층이상운입자결구정현고밀도간빙품포과습빙품적정황.
The phase of hydrometeor is one of the most important microphysics characteristics of cloud. The development of dual-polarimetric weather radar makes the retrieval of the hydrometeor phases possible theoretically, which has been one of the hottest applications of the dual-polarimetric radar. The fuzzy logic has been extensively used in the classification of hydrometeor now, and become the dominant technique in this field. Through continuously studying in statistics with more and more in situ measurements, the parameters in fuzzy logic algorithm have become relatively steady for individual dual-polarimetric radar in operational use. The evolution of hydrometeor phase in the cloud process is an important aspect to the research of water microphysical circular in the cloud-precipitation system, and plays great role in many meteorological fields, such as weather modification, aviation security, weather model, and so on. However the studies on the changing of the hydrometeor phase with time series of radar data are relatively immature, publications in which are seldom seen. A fuzzy logic system for classifying hydrometeors based on the combination of polarimetric radar measurements and conventional observation data is described, and a Beta membership function is utilized for the fuzzification, the parameters of which are also given based on the former statistics achievements for the S-band radar. The input variables include radar reflectivity, L_(DR), Z_(DR) and the height of 0℃ and -40℃ layer, and the output types are drizzle, rain, low-density dry ice crystal, high-density dry ice crystal, wet ice crystal, dry graupel, wet graupel, small hail, large hail, sleet, and cloud droplet. Then a case study on an evolution of the hydrometeor phase in a stratiform cloud precipitation process is analyzed based on the CAMRa radar and RAOBs data, which takes place at Chilbolton the UK summer morning, and lasts approximate 39 minutes. The whole process is divided into three phases including the initial phase, mature phase and the dissipating phase, for each phase a analysis on the changing of the hydrometeor type is given based on the classified results of all the radar observations in it, and the results show that in the initial phase stratiform cloud has a layered structure of hydrometeor types including high-density dry ice, wet ice crystal and liquid droplet from top to bottom; the core of the large-echo region is filled by large ice crystals, and the other area in the large-echo region is filled by liquid hydrometeors in initial phase; from initial phase to mature phase liquid hydrometeors on the top of the large-echo region have a trend of freezing; in the dissipating phase the 0℃ layer bright band disappears gradually, on the top of which a wet ice crystals are wrapped by high-density dry crystal.