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双线偏振多普勒天气雷达估测混合区降雨和降雹方法的理论研究
黎平 Liu Liping
大气科学 , 2002, DOI: 10.3878/j.issn.1006-9895.2002.06.05
Abstract: 利用冰雹形状和空间取向的模型及降雹和降雨的滴谱分布,分析了C波段双线偏振雷达探测的降雨和冰雹的反射率因子ZH、差反射率因子ZDR和差传播相移KDp的取值范围,及混合区降水中不同大小的降雨降雹强度对这些参量的贡献.结果表明:对于C波段双线偏振雷达来讲,当降雹达到一定强度后,反射率因子反而随降雹强度的增大而减小,反射率因子和降雹强度不一定是一一对应关系,降雹的KDp与相态、空间取向和雹块的尺度均有关系.在混合性降水中,ZH的主要贡献来自冰雹,而KDp主要取决于降雨的大小,降雨和降雹对ZDR均有明显的影响,降雨的ZH和KDP有比较好的对应关系.在此基础上给出了利用ZH、ZDR和KDp定量估测相态混合区冰雹和降雨对应的反射率因子、降雨强度的方法,并从滴谱变化、雷达探测精度和冰雹对KDp的影响分析了这种方法的估测精度.
A Theoretical Study of Estimations of Rain and Hail Rates in Mixed-Phase Areas with Dual Linear Polarization Radar
双线偏振多普勒天气雷达估测混合区降雨和降雹方法的理论研究

Liu Liping,
黎平

大气科学 , 2002,
Abstract: By using the model of hail shape, orientation and size distributions of rain and hail, the values of reflectivity (ZH ), differential reflectivity (ZDR ) and differential propagation phase shift (KDP) in rain and hail areas, and contributions of rain and hails to those parameters are examined. The results show that the reflectivity of hail measured by C band polarization radar decreases with hail rate when hail rate is large, the KDP in hail is related with the shape, orientation and size of hail. In the mixture of rain and hail, the main contribution of ZH is from hail, and rain is primary factor to affect KDP, and both rain and hail have contribution to ZDR , and ZH and KDP in rain have good correlation. Then we introduce a simple method to estimate hail and rain rates in mixed phase area with ZH, ZDR and KDP , analyze the measured errors with size distribution, radar measurement errors and effects of hail on KDP .
Optical Transmission Spectrum of Thue-Morse structure Containing Negative Index Materials
含负折射率材料的Thue-Morse序列结构的光学透射谱

Luo Liping,Liu Nianhua,
黎平
,念华

光子学报 , 2005,
Abstract: The transmission spectrum of Thue-Morse photonic crystals constructed by positive and negative index materials alternately was investigated.The transmittance was calculated by the recursion relations of the transfer matrix elements.Numerical analyses show that a zero-n gap exists in the TM multilayer system.Comparing with the Bragg gap,this gap is less sensitive to the incident angle and the polarization.The position of gap will not change with the order number of the TM sequence.Meanwhile,the field distribution is investigated for completely transparent states.The field distributions are analogous to the lattice structure.
A Study of Method and Accuracy of Rainfall Rate and Liquid Water Content Measurements by Dual Linear Polarization Doppler Radar
双线偏振多普勒天气雷达遥测降水强度和液态含水量的方法和精度研究

Liu Liping,Ge Runsheng,Zhang Peiyuan,
黎平
,葛润生,张沛源

大气科学 , 2002,
Abstract: 利用雨滴谱的Г分布和散射计算模式,研究了C波段双线偏振多普勒天气雷达遥测降水强度、液态含水量和识别降水粒子相态的方法,给出了利用反射率因子ZH、差分反射率因子ZDR、差传播相移KDP反演降水强度和液态含水量的三种公式以及这三个物理量的关系公式,并从雨滴谱的变化和雷达测量误差两方面比较了几种方法的测雨精度.结果表明:雨滴谱在很大范围变化时,利用ZDR和KDP可以很好地反演出降水强度和液态含水量,它受滴谱分布的影响不大,它的探测精度优于(ZH,ZDR)方法.单参数KDP方法优于传统的Z-R关系方法.同时给出的ZH与ZDR和KDP关系公式也基本不受雨滴谱变化的影响,它可以用于降水粒子相态的识别.双参数方法的测量误差主要来源于雷达测量ZDR和KDP的误差,特别是KDP的误差,改善KDP的测量误差是发挥双线偏振多普勒雷达探测降水强度或液态含水量潜力的关键.
Study of Hail with C B and Dual Linear Polarization Radar
用C波段双线偏振雷达研究冰雹云

Liu Liping,Xu Baoxiang,Wang Zhijun and,
黎平
,徐宝祥,王致君,

大气科学 , 1992,
Abstract: This paper presents the calculations of the scattering properties of hydrometeors with different shapes and phases. Based on these properties and ZDR features of rain and clond echos, the dual linear polarization radar RHI data observed during hailstorm processes on August 9 and August 30, 1990 are analysed . We deduced that the area with negative ZDR values corresponded to hail shafts where may appear large oblate hailstones and small conical hailstones, and the area with great positive Z D R values corresponded to raining area . The Z D R greater than 5dB was caused by huge raindrops (D>0.5cm). It is possible to detect the presence of hail using ZDR as a criterion. Compared with a S-band radar, the C-band dual linear polarization radar is unique in several aspects : the Z DR values are larger in raining area and smaller and negative in hail shooting area , which are useful for the study of microphysics and spatial structure of storms. The dual linear polarization radar will be impartant to cloud physics and weather modification .
双线偏振多普勒天气雷达遥测降水强度和液态含水量的方法和精度研究
黎平 Liu Liping,葛润生 Ge Runsheng,张沛源 Zhang Peiyuan
大气科学 , 2002, DOI: 10.3878/j.issn.1006-9895.2002.05.12
Abstract: 利用雨滴谱的Г分布和散射计算模式,研究了C波段双线偏振多普勒天气雷达遥测降水强度、液态含水量和识别降水粒子相态的方法,给出了利用反射率因子ZH、差分反射率因子ZDR、差传播相移KDP反演降水强度和液态含水量的三种公式以及这三个物理量的关系公式,并从雨滴谱的变化和雷达测量误差两方面比较了几种方法的测雨精度.结果表明:雨滴谱在很大范围变化时,利用ZDR和KDP可以很好地反演出降水强度和液态含水量,它受滴谱分布的影响不大,它的探测精度优于(ZH,ZDR)方法.单参数KDP方法优于传统的Z-R关系方法.同时给出的ZH与ZDR和KDP关系公式也基本不受雨滴谱变化的影响,它可以用于降水粒子相态的识别.双参数方法的测量误差主要来源于雷达测量ZDR和KDP的误差,特别是KDP的误差,改善KDP的测量误差是发挥双线偏振多普勒雷达探测降水强度或液态含水量潜力的关键.
毫米波云雷达功率谱密度数据的检验和在弱降水滴谱反演中的应用研究
黎平 LIU Liping,谢蕾 XIE Lei,崔哲虎 CUI Zhehu
大气科学 , 2014, DOI: 10.3878/j.issn.1006-9895.2013.12207
Abstract: 本文首先利用数值模拟的方法,分析了利用毫米波云雷达功率谱密度反演雨滴谱时,降水粒子米散射效应、空气湍流、空气上升速度等对雨滴谱和液态水含量等参数反演的影响;建立了功率谱密度处理及其直接反演雨滴谱、液态水含量、降水强度和空气上升速度的方法;并利用2012年7月在云南腾冲观测的二次弱降水数据,采用毫米波雷达和Ku波段微降水雷达观测的回波强度、径向速度垂直廓线以及780m高度上的功率谱密度对比的方法,以及毫米波云雷达观测的780m高度上功率谱密度、回波强度与地面雨滴谱计算得到的这些量的对比方法,分析了毫米波雷达数据的可靠性;并将780m高度上毫米波雷达反演的雨滴谱与地面雨滴谱数据进行了对比,分析了毫米波雷达反演的雨滴谱的准确性;分析了毫米波雷达回波强度偏弱的原因,讨论了该高度以下降水对毫米波雷达衰减的影响。结果表明:空气湍流对弱降水微物理参数反演影响不大,而空气上升速度和米散射效应均对反演结果有一定影响;毫米波雷达观测到的径向速度和功率谱密度与微降水雷达比较一致,回波强度的垂直廓线的形状与微降水雷达也比较一致,但毫米波雷达观测的回波强度偏弱;与雨滴谱计算值相比,毫米波雷达观测的低层的回波强度也偏弱,天线上的积水是造成毫米波雷达回波强度变弱的主要原因。毫米波雷达观测的低层的功率谱密度与地面雨滴谱观测的数据形状比较一致,但有一定的位移。毫米波雷达反演的雨滴谱与地面观测的谱型和粒子大小也比较一致。这些结果初步验证了毫米波雷达观测的功率谱密度及其反演方法的可靠性。
Comparitive Study on Dual Linear Polarization Radar Measuring Rainfall Rate
双线偏振雷达测雨效果的对比分析

Liu Liping,Qian Yongfu,Wang Zhijun,Chu Rongzhong,
黎平
,钱永甫,王致君,楚荣忠

大气科学 , 1996,
Abstract: The database is the C-band dual linear polarization radar data and ground raingage network data for 15 stratus and 12 convective rain processes during summers of 1993 and 1994. In this paper, we estimate systematically the measurement accuracy of rainfall rate by the dual linear polarization radar and conventional radar. The result indicates that the underestimation of the rainfall rate during heavy rain and the overestimation during light rain become small by ZDR method. ZDR method can improve the measurement of light and moderate rainfall rate. The overestimation of the rainfall rate during heavy rain by ZDR technique is possibly related with the existence of ice phase hydrometeors.
An Experimental and Theoretical Study of Electromagnetic Backscattering from the Axially-Symmetric Oblate Water and Ice Ellipsoids
扁椭球形雨滴和冰粒后向散射实验与理论研究

Wang Qing''an,Liu Liping,Chao Zengming,Zhang Yaopei,
王庆安
,黎平,巢增明,张尧培

大气科学 , 1996,
Abstract: This paper describes the experimental simulation and measuring technique of the scattering from oblate water and ice ellipsoids. The measuring results of the backscatter cross-section are given for a series of oblate ellipsoids. The backscatter cross-sections of oblate allipsoids and those of the corresponding sphere of equal valume are calculated using the Extended Boundary Condition Method and Mie formula respectively. The experimental data obtained are reliable. The experimental data are compared with theoretical results. Some useful conclusions are thus drawn.
Analysis of the Characteristics of Mesoscale Disturbance for Landfalling Typhoon Matsa
登陆台风Matsa(麦莎)中尺度扰动特征分析

JI Chunxiao,ZHAO Fang,GAO Shouting,LIU Liping,
冀春晓
,赵放,高守亭,黎平

大气科学 , 2012,
Abstract: Doppler radar reflectivity and the surface automatic weather stations (AWS) wind observations demonstrate that the mesoscale cyclonic eddies at the low level are active in the spiral-cloud bands of landfalling typhoon Matsa. Numerical simulation has been carried out to investigate the evolution characteristics of typhoon Matsa in 2005 after its landfalling by using the new-generation mesoscale weather research and forecasting (WRF) model, and the four-dimensional variational Dopple radar analysis system (4D-VDRAS) is used to retrieve single-Doppler velocity. Then a preliminary study has been made on the mesoscale features of typhoon Matsa after landfalling in parallel with diagnostic analyses of the conversion of kinetic energy and vorticity between typhoon Matsa and mesoscale systems on the area mean basis. Results show that: (1) The results of numerical simulation and Doppler radial velocity retrieval indicate that the mesoscale cyclonic eddies at the low level are active in the spiral-cloud bands of landfalling typhoon Matsa, and there is severe mesoscale upward movement accompanying the mesoscale cyclonic eddies. The stronger the mesoscale upward movement is, the larger Doppler radar reflectivity is.(2) The diagnostic results of the kinetic energy conversion between Matsa and mesoscale systems demonstrate that the mesoscale cyclonic eddies at the low level obtain kinetic energy from landfalling typhoon Matsa to develop, whilst Matsa obtains kinetic energy from the mesoscale disturbances in the upper layers to be sustained after landfalling.(3) The diagnostic results of the vorticity conversion between Matsa and mesoscale systems show that Matsa obtains positive vorticity from the mesoscale cyclonic eddies at the low levels by means of the mesoscale upward movement, but in the upper layers, both the mesoscale horizontal and vertical movements play important roles. Therefore, the positive cyclonic vorticity is transported continuously to Matsa, and Matsa could be sustained for a long time after landfalling.
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