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机载多普勒天气雷达及应用研究进展 总被引：1，自引：1，他引：0
机载多普勒天气雷达由于其灵活机动性,在台风、暴雨等灾害性天气系统中尺度三维精细结构研究中发挥着重要作用.对机载多普勒天气雷达技术及其资料应用进行了概要性综述,主要从机载多普勒天气雷达发展历程、4种主要机载多普勒雷达技术特点、雷达天线扫描策略、单多普勒雷达风场反演技术、双多普勒雷达风场反演技术、雷达资料同化以及目标观测等方面进行阐述和分析;着重讨论了应用中需要解决的问题.最后,指出发展具有快速扫描和双偏振功能的机载相控阵多普勒雷达是机载天气雷达的发展方向,它可以获取高时空分辨率的探测数据,能够对云和降水系统的三维精细动力结构、热力结构以及微物理结构等进行综合研究. 相似文献
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贵州地处青藏高原东部斜坡，地形复杂、纬度较低，是强对流天气的多发区，冰雹、暴雨、风暴灾害给全省工农业生产带来严重危害。我们结合贵州探空站点稀少、又无多普勒雷达的具体情况，采用矩不变量和相关法，在常规天气雷达上遥测回波块内部运动，编制了能完成资料预处理、特征量计数、模式识别、流场计算、存贮、打印、显示回波场、风场、散度场、涡度场的实用软件，且程序设计汇编化、管理菜单化、结构模块化、计算表格化、数据公有化，在２４０×２４０ｋｍ２的区域（网格距为１ｋｍ）中计算回波区流场的时间仅为二分钟。理论分析和数值实验表明，结果合理。用南京气象学院多普勒雷达实测的回波资料对比，其准确率可达８０％以上，若去掉因边缘效应产生的错误风矢量，准确率可达９０％以上。使用该方法，可随时大致了解降水区内部水平流场结构，有利于中小尺度天气的监测和预报，为减灾防灾等部门提供风场、散度场、涡度场等信息。 相似文献
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利用WRF3D-Var同化多普勒雷达反演风场试验研究 总被引：2，自引：0，他引：2
为了将C波段雷达风场资料更好地应用于数值预报模式中,利用两步变分法反演多普勒雷达风场资料,并处理成标准的常规探空资料,以WRF模式及其三维变分同化系统为平台,针对2013年6月19日发生在天水的一次强暴雨过程进行同化雷达反演风的试验研究.试验结果表明:同化雷达反演风场后,对降水预报的改进能维持12h,尤其同化雷达反演风场后3~9h效果非常显著;0~3h作用不是很明显;9~12h预报具有一定的正作用.另外,循环同化比同化一次效果好,但并不是同化次数越多越好.因此,同化C波段雷达反演风场后,对降水预报具有一定的正作用. 相似文献
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毫米波测云雷达的特点及其研究现状与展望 总被引：17，自引：2，他引：15
云在大气的能量分配、辐射传输,尤其是水循环系统中有不可忽视的作用。云探测对云物理、人工影响天气、气候变化和航空航天等领域有重要意义,是大气科学研究的热点之一。尽管目前已经发展了很多种遥感设备对云进行观测(如激光雷达、卫星、云幂仪等),但这些设备无法得到高时空分辨率的云水平和垂直结构,而毫米波雷达是云三维精细结构探测的重要工具。由于毫米波雷达具有更接近小粒子尺度的短波长,因此更适合用来探测弱云,同时毫米波雷达也存在衰减严重的缺点。介绍了毫米波雷达的特点以及其探测小粒子的优势;对比分析了其与新一代多普勒天气雷达、晴空风廓线雷达的差异,得出：毫米波雷达具有高时空分辨率,能够更精确地反映云的垂直和水平结构,比普通天气雷达更适合监测云的变化。概括了国内外毫米波测云雷达的发展现状以及在云物理研究方面的情况,并展望了国内毫米波雷达未来研究的方向。 相似文献
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洪水预报中的不确定性是由作为输入的降水观测和预报的误差所决定的。误差大小受雨量计站网密度（大多与天气雷达联合运用），降水强度和所采用的降水预报方法的影响。在不更颠南部，采用一种经验方法来量化降水观测及预报的不确定性性，数据由两个密集的雨量计站网和天气雷达共同提供。降水不确定性对洪水预报的影响，通过在伦敦附近的泰晤士流域一个综合实验研究进行了检验。此项研究就模型和流域对洪水预报不确定性的相地影响也很 相似文献
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地形对波束遮挡是影响雷达观测资料质量的重要误差源之一。国家防汛抗旱指挥系统二期工程建设了天气雷达应用系统,系统利用新一代天气雷达背景场特征资料客观分析技术计算出雷达站周围环境对雷达波束造成遮挡影响的背景场特征资料(挡角图、等射束高度图和波束遮挡能量耗损率图)。详细介绍了新一代天气雷达背景场特征资料计算原理和方法,并提出利用雷达回波概率特征方法,将计算出的背景场特征资料与不同仰角雷达回波统计的概率空间分布进行对比分析,验证了新一代天气雷达背景场特征资料的正确性,为后期雷达波束能量遮挡进行定量订正提供依据。 相似文献
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多普勒雷达图像在地质灾害气象预警中的应用——以湖南省新邵县“2005．05．31”特大地质灾害气象预警为例 总被引：1，自引：0，他引：1
本文介绍了湖南地质灾害概况,通过对暴雨诱发地质灾害的机理分析和多普勒雷达系统监测暴雨的可能性分析,选取地质灾害频发的湖南省作为典型研究区,通过多普勒雷达图像地质灾害气象反演分析和灾害识别研究,精确地预报了湖南省新邵县“2005．05．31”特大地质灾害,论证多普勒雷达是监测突发性地质灾害的有效手段。 相似文献
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WMO第八届阳江国际探空比对辅助遥感综合试验 总被引：1，自引：0，他引：1
第八届阳江国际探空比对辅助遥感综合试验为分析探空仪系统在高空出入云的温湿特性,评估高层云红外辐射对温度传感器的影响以及湿度传感器的系统偏差提供有力帮助。通过试验,还评估了国产X波段双偏振雷达与毫米波云雷达的优缺点和性能差异,以及国产多普勒激光雷达、微脉冲激光雷达的探测性能和应用能力,在改进微波辐射计温湿反演算法、X波段偏振雷达参数的云中粒子相态模糊逻辑识别算法,以及多普勒天气雷达风场反演、云分类算法、高空业务测风算法等方面开展广泛研究并取得一定进展。试验还利用先进的各类遥感设备对阳江热带地区的云、局地对流以及海陆风系统的结构进行了观测和分析,取得了较好的研究结果。 相似文献
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S. Abhilash Someshwar Das S. R. Kalsi M. Das Gupta K. Mohankumar J. P. George S. K. Banerjee S. B. Thampi D. Pradhan 《Journal of Earth System Science》2007,116(4):275-304
Obtaining an accurate initial state is recognized as one of the biggest challenges in accurate model prediction of convective
events. This work is the first attempt in utilizing the India Meteorological Department (IMD) Doppler radar data in a numerical
model for the prediction of mesoscale convective complexes around Chennai and Kolkata. Three strong convective events both
over Chennai and Kolkata have been considered for the present study. The simulation experiments have been carried out using
fifth-generation Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) mesoscale model (MM5) version
3.5.6. The variational data assimilation approach is one of the most promising tools available for directly assimilating the
mesoscale observations in order to improve the initial state. The horizontal wind derived from the DWR has been used alongwith
other conventional and non-conventional data in the assimilation system. The preliminary results from the three dimensional
variational (3DVAR) experiments are encouraging. The simulated rainfall has also been compared with that derived from the
Tropical Rainfall Measuring Mission (TRMM) satellite. The encouraging result from this study can be the basis for further
investigation of the direct assimilation of radar reflectivity data in 3DVAR system. The present study indicates that Doppler
radar data assimilation improves the initial field and enhances the Quantitative Precipitation Forecasting (QPF) skill. 相似文献
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Yu-Kun Qian Shiqiu Peng Shun Liu Shumin Chen Ziqian Wang Qilin Wan Zitong Chen 《Natural Hazards》2018,94(1):279-298
Observations by Doppler weather radar are crucial for nowcasting and short-time forecasting of severe weather events as they bring in refined information of the atmosphere. However, due to the inevitable noises and non-meteorological signals, they cannot be assimilated straightforwardly into a numerical model. In the present study, assimilation of the radial component of wind velocity observed by two Doppler radars is performed in the numerical simulation of Supertyphoon Rammasun (2014) just before its landfall. After several quality-control steps, the radar-observed radial velocities are de-aliased, noise-reduced and assimilated into the model to improve initial conditions for the high-resolution simulation. Results show that only when using global background error covariance matrix can the observational increment be properly assimilated into the model, correcting large-scale background steering flow and yielding a simulated track close to the observed one. However, little improvement is found in simulating the TC core-scale structures by the assimilation of radar velocity as compared to the radar-observed flow, primarily due to the insufficient spatial resolution of the model that may lead to the incorrect representation of the TC core structure and the rejection of some core-region observations during the data assimilation procedure. Moreover, assimilation-induced asymmetries consume a certain portion of mean kinetic energy, preventing the simulated Rammasun from axisymmetrization and thus intensification as compared with the non-assimilated experiment. 相似文献
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《Atmósfera》2014,27(1):21-34
The Romanian National Meteorological Administration (NMA) radar network consists of five S-band and four C-band radars. Observation of convection in Romania through the Doppler radar network offered a new perspective in understanding the climatologic risk of certain regions and mesoscale environments. Highly organized convective systems, such as supercells, are better observed and their subsequent threat can be better anticipated during the nowcasting process using Doppler velocity fields and detection algorithms such as mesocyclones (MESO) and tornadic vortex signature (TVS). However, for warning purposes, these tools cannot be used without a subjective validation because of the associated errors and limitations of radar observations. In this paper several cases are presented where the presence of large hail inside the storm produced a radar artifact named three-body scatter signature (TBSS) that disturbed the Doppler velocity field. The cases presented were observed with S-band radars and were associated with hail reports on the ground. The first case shows a TBSS whose radial Doppler velocities are negative due to the falling hydrometeors. The second case is a less frequent event; there the Doppler velocities in the TBSS region are positive due to the updraft. The third case has both positive and negative values in the TBSS region; it ocurred in a supercell that affected the city of Varna in Bulgaria with large hail. The positive values were associated with the overhang region in the rotational updraft at upper heights, while the negative values in the regions outside the rotational updraft at lower heights, were associated with the downdrafts. Features produced by the TBSS have perturbed the output of the MESO and TVS algorithms by introducing false strong values of wind shear that have been interpreted as rotation. Thus false mesocyclonic and tornadic vortex signatures were generated. In some of the cases large hail and weak tornadoes were reported, so the presence of a TBSS was a challenge for the nowcasters. In the last part of the paper we analyze the link between the TBSS appearance with reports of large hail at the ground in 2009 within the coverage area of the Romanian S-band radars, which also cover parts of Hungary, Bulgaria, the Republic of Moldova and Serbia. The results show that the TBSS artifact is a strong indicator of large-size hail. 相似文献
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为解决低流速、受变动回水影响等较复杂监测环境下的流量在线监测问题,依据声学多普勒频移及雷达波测速的方法原理,结合新运粮河入滇池口监测断面复杂的水文监测条件实际,采用非接触式雷达波传感器与接触式水平ADCP传感器组合成一套完整的在线流量监测系统,实现河流水表面流速和水下指标流速的同步实时数据采集,再将同步采集的水表面流速和水下指标流速同时输入模型模拟监测断面流场、流速分布,再计算实时流量后,通过GPRS信道传送到中心站服务器,对数据进行分析处理、存储、转录、发布,实现WEB、手机APP远程实时流量、工作状态等查询功能。经近一年的运行,系统正常稳定。 相似文献
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In this paper, impact of Indian Doppler Weather Radar (DWR) data, i.e., reflectivity (Z), radial velocity (Vr) data individually and in combination has been examined for simulation of mesoscale features of a land-falling
cyclone with Advance Regional Prediction System (ARPS) Model at 9-km horizontal resolution. The radial velocity and reflectivity
observations from DWR station, Chennai (lat. 13.0°N and long. 80.0°E), are assimilated using the ARPS Data Assimilation System
(ADAS) and cloud analysis scheme of the model. The case selected for this study is the Bay of Bengal tropical cyclone NISHA
of 27–28 November 2008. The study shows that the ARPS model with the assimilation of radial wind and reflectivity observations
of DWR, Chennai, could simulate mesoscale characteristics, such as number of cells, spiral rain band structure, location of
the center and strengthening of the lower tropospheric winds associated with the land-falling cyclone NISHA. The evolution
of 850 hPa wind field super-imposed vorticity reveals that the forecast is improved in terms of the magnitude and direction
of lower tropospheric wind, time, and location of cyclone in the experiment when both radial wind and reflectivity observations
are used. With the assimilation of both radial wind and reflectivity observations, model could reproduce the rainfall pattern
in a more realistic way. The results of this study are found to be very promising toward improving the short-range mesoscale
forecasts. 相似文献