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Determination of Refractive Index Structure Constant with Wind Profile Radar Data
风廓线雷达对大气折射率结构常数的探测研究

RUAN Zheng,HE Ping,GE Run-Sheng,
阮征
,何平,葛润生

大气科学 , 2008,
Abstract: Based on the turbulent backscattering theory,the calculation method of the refractive index structure constant(RISC) is devised.Through analyzing the different data from Wind Profile Radar(WPR) with different observing modes,it is found that the result of the RISC depends on the adequacy of radar parameters,the method for determining the Signal-to-Noise Ratio(SNR) and the confirmation of the integral accumulated gain.The standardized processing method is put forward for the different observing modes of WPR.This method is used to process the data from two tropospheric WPRs with five observing modes in Beijing in 2005.After consistency checking for data,the vertical RISC profiles is obtained by using the processing method.The rationality analysis is conducted,including the vertical structure and seasonal change analysis and the comparison with results of other simplified models and radiosonde data.It is concluded:(1) The RISC vertical profiles from different tropospheric WPRs are identical by using the standardized processing method of considering the accurate return signal power and SNR.(2) The analysis of the RISC vertical profiles retrieved from the data of two tropospheric WPRs in Beijing in 2005 indicates that the RISC decreases as exponential function with altitude,and the vertical decrease rate is 2.6 dB/km in summer,similar to the results of other detecting methods home and abroad.The RISC simplified models in Beijing have been gotten.The result of vertical RISC distribution in winter of Beijing is close to the winder result of Doviak's in Denver.(3) There is obvious seasonal variation in the RISC vertical structure retrieved from WPRs at different altitudes.It is mainly because that RISC is one or two orders of magnitude larger in the warm and humidity season than in the dry and cold season in the middle layer of troposphere,but there is little difference between lower and upper layers.(4) A comparison case study was conducted with the output by using radiosonde data at the same location.The structures of the profiles are similar and there is obvious discontinuous stratification at the same altitude.
风廓线雷达对大气折射率结构常数的探测研究
阮征 RUAN Zheng,何平 HE Ping,葛润生 GE Run-Sheng
大气科学 , 2008, DOI: 10.3878/j.issn.1006-9895.2008.01.12
Abstract: 基于湍流散射理论,构建了风廓线雷达(WPR)强度信息对大气折射率结构常数的估算方法。经过对WPR多种探测模式探测数据的估算分析,发现雷达参数的确切选用、信噪比(SNR)测量方法的合理性以及信号累积得益的认定对大气折射率结构常数的准确估算有较大的影响,为此提出适合WPR多种探测模式对该估算值规范化处理方法。利用北京两部对流层风廓线雷达五种探测模式于2005年获取的部分观测数据,进行了规范化计算及对比分析。结果表明,邻近时刻的不同风廓线雷达探测估算结果有较好的一致性,其垂直分布结构合理,呈指数形式,统计结果与国内外的分析研究结果较为吻合。
A Study of Fuzzy Logic Method in Classification of Hydrometeors Based on Polarimetric Radar Measurement
模糊逻辑法在双线偏振雷达识别降水粒子相态中的研究

CAO Jun-Wu,LIU Li-Ping,GE Run-Sheng,
曹俊武
,刘黎平,葛润生

大气科学 , 2005,
Abstract: The polarimetric radar measurements are sensitive to the types, shapes, and sizes distribution . It is a useful remote sensing tool for the study of hydrometeor classification. A fuzzy logic system for classification of hydrometeor type based on polarimetric radar measurements is described. First, the membership function of fuzzy logic method is constructed according to the feasibility of scattering and orientation of different kinds of hydrometeors, and the asymmetric trapezoidal membership function is chosen as the form of the membership functions. Then, the method of classification of hydrometeors based on polarimetric radar measurement is discussed in detail by using KOUN radar observation data. The feasibility and rationality of its application in operation are also analyzed. The main conclusions are got as follows: (1) Fuzzy logic method based on polarimetric radar data can be used in hydrometeors classification, and the results are basically reasonable based on two case studies. It can reveal the development course of weather system, and classify hydrometeor types, but still need be further studied. (2) Although the classification result is coarse and has no definite value, it still can be used to initialize meso\|scale numerical weather prediction models, offer reference to daily weather forecast and evaluate the results of artificial weather modification. It can provide reference in the polarimetric radar operation of China. (3) It may be not hail but big rain drops although the value of reflectivity is larger than 60 dBZ based on data analysis.
模糊逻辑法在双线偏振雷达识别降水粒子相态中的研究
曹俊武 CAO Jun-Wu,刘黎平 LIU Li-Ping,葛润生 GE Run-Sheng
大气科学 , 2005, DOI: 10.3878/j.issn.1006-9895.2005.05.15
Abstract: 根据不同相态降水粒子的散射和空间取向等特征建立了基本形式为不对称的T型函数的模糊逻辑识别的隶属函数,完善了该识别方法的流程,并利用美国KOUN雷达的观测资料,详细讨论了利用双线偏振雷达观测资料识别降水粒子相态的方法,并对其在实际业务运用中的合理性和可行性进行分析探讨.通过分析,作者认为:(1)利用模糊逻辑方法处理双线偏振雷达测量到的偏振参数,可以识别降水区域的降水粒子相态,反映降水区域的相态结构,识别的结果基本合理,但还需要资料作进一步的研究.(2)从实际资料的分析结果来看,虽然利用模糊逻辑法识别降水粒子相态得到的结果比较粗,没有明确的数据特征值,但是它基本上能反映各种降水粒子的相态结构,其识别的结果对目前日常的天气预报参考和人工影响天气的作业指挥和效果评估来说还是符合可用的.为中国国内未来的双线偏振雷达业务运行提供参考和帮助.(3)根据有限的观测资料分析表明,降水区域中出现60dBZ以上的回波强度,并不一定就会出现冰雹,还有可能是大粒子的液态降水.综合考虑双线偏振雷达的测量参数,可以得到更合理的结果.
An Improved Method on the Simultaneous Transmission Scheme of Dual Polarimetric Weather Radar
双偏振天气雷达同时收发模式的一种改进方法

LIANG Hai-He,XU Bao-Xiang,LIU Li-Ping,GE Run-Sheng,
梁海河
,徐宝祥,刘黎平,葛润生

大气科学 , 2006,
Abstract: The simultaneous transmission scheme of dual polarimetric radar(PR) is now paid more attentions,but there is a bigger error on differential reflectivity in this scheme.The paper studies the relations between the phase difference of dual transmission port and the error of differential reflectivity,and the infections of dual transmission power and receiver gain distinction to differential reflectivity.In terms of the necessary of rainfall measurements and hydrometeor discrimination,an improved method for simultaneous transmission is advanced based on the theory study,and the simultaneous signal processing scheme is provided.This new improved method can increase the ability of measurements and discrimination via reducing differential reflectivity error through changing phase between H and V channels.This scheme has many advantages including:(1) improving measurement quality by changing phase between H and V channels,(2) enhancing SNR and signal intensity of weak echo in spite of co-polar or cross-polar port,(3) obtaining elliptic depolarization ratio(EDR),(4) transmitting linear,circular or elliptic polarization at different elevations in one volume scan,and(5) eliminating ferrite switch and phase alternation for different elevations.Polarimetric radar development is a complicated,synthetic and scientific subject,every polarimetric scheme has some advantages and disadvantages,therefore the goal of this thesis is to consider the theory and technology of PR confronted in China.This improved method should be further examined and developed in practice.
A Study of Mesoscale Wind Structures in Heavy Rainfall System of Merging Cloud with Dual-Doppler Radar
一次混合云暴雨过程风场中尺度结构的双多普勒雷达观测研究

LIU Li-Ping,SHAO Ai-Mei,GE Run-Sheng,LIANG Hai-He,
刘黎平
,邵爱梅,葛润生,梁海河

大气科学 , 2004,
Abstract: 利用国家重点基础研究发展规划项目"我国重大气象灾害形成机理和预测理论研究"2002年外场试验首次获取到的双多普勒雷达资料,研究了7月22~23日在长江中游的宜昌、荆州区域暴雨回波和风场的中尺度结构及演变过程.结果表明:本次暴雨是混合云降水所致,在层状云降雨区内有许多对流单体,这些对流单体常以带状结构组成回波群,对流云的回波强度和风场有明显的中尺度结构,与周围的层状云有很大差别.西南气流和东风形成的中尺度切变和辐合是造成强对流降水的主要原因,风场的中尺度结构主要发生在4 km以下的中下层.在对流回波周围,经常有中尺度切变、涡旋、辐合和辐散存在,这些风场的中尺度结构与对流云的演变有密切的关系,对强降水的发生和维持有重要影响.此项工作为分析中尺度暴雨的形成和演变机理提供了依据.
A Study of Drop-Size Distribution in Precipitation Cloud from Wind Profile Radar
风廓线雷达探测降水云体中雨滴谱的试验研究

WANG Xiao-lei,RUAN Zheng,GE Run-sheng,CHEN Zhong-rong,
王晓蕾
,阮征,葛润生,陈钟荣

高原气象 , 2010,
Abstract: 对风廓线雷达探测降水时出现的双峰型功率谱密度分布的回波, 进行大气返回信号和降水返回信号的剥离, 由大气返回信号求出环境大气的垂直运动, 导出降水质点下降末速度的功率谱密度分布, 进而求出云体中的雨滴谱分布。对两次降水进行了雨滴谱反演试验, 提取了不同高度上30多份雨滴谱分布, 雨滴谱分布基本上呈现出指数分布形式。指数拟合后求出雨滴谱的浓度参数N0由几百到几千m-3mm-1, 尺度参数λ为3.8~4.5 mm-1。试验中, 还由反演的雨滴谱估算出云中含水量, 得出降水云体中含水量随高度的分布, 与附近多普勒天气雷达观测进行了比较。风廓线雷达与多普勒天气雷达探测到的回波强度随高度分布基本一致, 云中含水量估算的均值基本相同, 而风廓线雷达由雨滴谱估算出的含水量随高度分布可以反映出雨滴谱变化的影响, 随高度分布更为精细。
Study on Bright Band Detection Using Wind Profiler Radar
风廓线雷达探测零度层亮带的试验研究

HUANG Yu-,RUAN Zheng-,GE Run-sheng,CHEN Zhong-rong,
黄钰
,阮征,葛润生,陈钟荣

高原气象 , 2011,
Abstract: L-band wind profile is used in coherent accumulation technology to rise radar sounding sensitivity, vertical measurement precipitation cloud body is applied,which can obtain the entire spectrum information of cloud body return signal of high resolution.The wind profiler is used to continuously detect the bright band appeared in stratiform cloud precipitation process on May 14,2009.The variation and evolution characteristics of return signal spectrum parameter(power,average Doppler velocity,speed spectral wi...
一次混合云暴雨过程风场中尺度结构的双多普勒雷达观测研究
刘黎平 LIU Li-Ping,邵爱梅 SHAO Ai-Mei,葛润生 GE Run-Sheng,梁海河 LIANG Hai-He
大气科学 , 2004, DOI: 10.3878/j.issn.1006-9895.2004.02.10
Abstract: 利用国家重点基础研究发展规划项目"我国重大气象灾害形成机理和预测理论研究"2002年外场试验首次获取到的双多普勒雷达资料,研究了7月22~23日在长江中游的宜昌、荆州区域暴雨回波和风场的中尺度结构及演变过程.结果表明:本次暴雨是混合云降水所致,在层状云降雨区内有许多对流单体,这些对流单体常以带状结构组成回波群,对流云的回波强度和风场有明显的中尺度结构,与周围的层状云有很大差别.西南气流和东风形成的中尺度切变和辐合是造成强对流降水的主要原因,风场的中尺度结构主要发生在4km以下的中下层.在对流回波周围,经常有中尺度切变、涡旋、辐合和辐散存在,这些风场的中尺度结构与对流云的演变有密切的关系,对强降水的发生和维持有重要影响.此项工作为分析中尺度暴雨的形成和演变机理提供了依据.
双偏振天气雷达同时收发模式的一种改进方法
梁海河 LIANG Hai-He,徐宝祥 XU Bao-Xiang,刘黎平 LIU Li-Ping,葛润生 GE Run-Sheng
大气科学 , 2006, DOI: 10.3878/j.issn.1006-9895.2006.04.09
Abstract: 目前,双偏振多普勒天气雷达的同时发射方式受到了普遍关注,作者针对该方式中偏振参量差分反射率存在较大误差的问题,研究了双发射通道相位差与差分反射率精度的关系,以及双通道发射功率差、接收机增益等对差分反射率的影响.在此基础上,给出了双偏振同时发射方式的一种改进方案,并讨论了该方案的优势和特点,设计了双偏振多普勒天气雷达同时发射方式下回波信号的处理框图.
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