期刊文献+
共找到34,896篇文章
< 1 2 250 >
每页显示 20 50 100
Fast coating analysis and modeling for RCS reduction of aircraft
1
作者 Haotian ZENG Xunwang ZHAO +2 位作者 Qin SU Yu ZHANG Hao LI 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第6期1481-1487,共7页
In order to fast analyze the aircraft Radar Cross Section(RCS) and accurately reduce it with Radar Absorbing Materials(RAM), a comprehensive analysis method based on Higher-Order Method of Moments(HOMOM), termed Local... In order to fast analyze the aircraft Radar Cross Section(RCS) and accurately reduce it with Radar Absorbing Materials(RAM), a comprehensive analysis method based on Higher-Order Method of Moments(HOMOM), termed Locally Coating Method(LCM), is proposed in this paper. There are two steps to fast analyze coatings for RCS reduction in this method: analyze the RCS of various parts before coating the aircraft;model a coating over the aircraft and analyze the wave absorbing effect of it. The aircraft RCS is calculated as a whole but analyzed in various parts by LCM, and thus the RCS contribution of different parts can be compared without disturbing the current continuity. A model expansion algorithm is also presented in LCM to model absorption coatings on specified aircraft parts for later stage RCS calculation of the coated aircraft. 展开更多
关键词 Coating modeling HIGHER-ORDER Method of Moments(HOMOM) RADAR Absorbing Materials(RAM) RADAR Cross Section(RCS) STEALTH technology
Advanced technology of high-resolution radar: target detection, tracking, imaging, and recognition
2
作者 Teng LONG Zhennan LIANG Quanhua LIU 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第4期1-26,共26页
In recent years, the performances of radar resolution, coverage, and detection accuracy have been significantly improved through the use of ultra-wideband, synthetic aperture and digital signal processing technologies... In recent years, the performances of radar resolution, coverage, and detection accuracy have been significantly improved through the use of ultra-wideband, synthetic aperture and digital signal processing technologies. High-resolution radars (HRRs) utilize wideband signals and synthetic apertures to enhance the range and angular resolutions of tracking, respectively. They also generate one-, two-, and even threedimensional high-resolution images containing the feature information of targets, from which the targets can be precisely classified and identified. Advanced signal processing algorithms in HRRs obtain important information such as range-Doppler imaging, phase-derived ranging, and micro-motion features. However, the advantages and applications of HRRs are restricted by factors such as the reduced signal-to-noise ratio (SNR) of multi-scatter point targets, decreased tracking accuracy of multi-scatter point targets, high demands of motion compensation, and low sensitivity of the target attitude. Focusing on these problems, this paper systematically introduces the novel technologies of HRRs and discusses the issues and solutions relevant to detection, tracking, imaging, and recognition. Finally, it reviews the latest progress and representative results of HRR-based research, and suggests the future development of HRRs. 展开更多
关键词 HIGH-RESOLUTION RADAR integrated detection and TRACKING multiple target TRACKING phase-derived velocity inverse synthetic APERTURE radar(ISAR) hierarchical classification CONVOLUTION neural network
Application of New Type of Detection Data in a Heavy Rainfall Process in Changsha 预览
3
作者 Huo Tao Shan Nan +2 位作者 Tang Xiaonan Fan Yu Liu Daxin 《气象与环境研究:英文版》 CAS 2019年第4期37-38,41共3页
Using detection data with high space-time resolution from the wind profile radar and millimeter wave cloud radar of Changsha station, and combining observation data of ground automatic station, heavy precipitation pro... Using detection data with high space-time resolution from the wind profile radar and millimeter wave cloud radar of Changsha station, and combining observation data of ground automatic station, heavy precipitation process in Changsha area from June 29 to July 1, 2017 was analyzed. The results showed that the atmospheric temperature advection was calculated by inversion of wind profile radar data of boundary layer, and it could intuitively analyze changes of atmospheric temperature advection before and after precipitation process. The variation characteristics of intensity, thickness and height of warm and cold advection in the upper and lower levels were highly related to the evolution of the precipitation process. The millimeter wave cloud radar can better reflect the vertical structure and evolution of the cloud over the observatory, and had certain indications for the structure characteristics of cloud before the starting of precipitation. When the strong reflectivity started to approach the ground, it also meant that heavy precipitation began to appear. 展开更多
关键词 WIND profile RADAR MILLIMETER wave CLOUD RADAR Temperature advection
在线阅读 下载PDF
High Resolution Radar Real-Time Signal and Information Processing 预览
4
作者 Teng Long Tao Zeng +8 位作者 Cheng Hu Xichao Dong Liang Chen Quanhua Liu Yizhuang Xie Zegang Ding Yang Li Yanhua Wang Yan Wang 《中国通信:英文版》 SCIE CSCD 2019年第2期105-133,共29页
Radar is an electronic device that uses radio waves to determine the range,angle,or velocity of objects.Real-time signal and information processor is an important module for real-time positioning,imaging,detection and... Radar is an electronic device that uses radio waves to determine the range,angle,or velocity of objects.Real-time signal and information processor is an important module for real-time positioning,imaging,detection and recognition of targets.With the development of ultra-wideband technology,synthetic aperture technology,signal and information processing technology,the radar coverage,detection accuracy and resolution have been greatly improved,especially in terms of one-dimensional(1D)high-resolution radar detection,tracking,recognition,and two-dimensional(2D)synthetic aperture radar imaging technology.Meanwhile,for the application of radar detection and remote sensing with high resolution and wide swath,the amount of data has been greatly increased.Therefore,the radar is required to have low-latency and real-time processing capability under the constraints of size,weight and power consumption.This paper systematically introduces the new technology of high resolution radar and real-time signal and information processing.The key problems and solutions are discussed,including the detection and tracking of 1D high-resolution radar,the accurate signal modeling and wide-swath imaging for geosynchronous orbit synthetic aperture radar,and real-time signal and information processing architecture and efficient algorithms.Finally,the latest research progress and representative results are presented,and the development trends are prospected. 展开更多
关键词 1D high RESOLUTION RADAR geosynchronous SYNTHETIC APERTURE RADAR REAL-TIME SIGNAL and information processing
在线阅读 下载PDF
桑吉轮与长峰水晶轮碰撞事故剖析与思考 预览
5
作者 郭丰田 《青岛远洋船员职业学院学报》 2019年第2期12-19,共8页
2018年1月6日,“桑吉”轮与“长峰水晶”轮发生碰撞事故,事故造成的灾难教训深刻。本文按照《1972年国际海上避碰规则》的相关条款及物理学等相关知识,着重从夜间驾驶台瞭望、驾驶台支持级船员瞭望等方面客观地对该碰撞事故做一剖析,并... 2018年1月6日,“桑吉”轮与“长峰水晶”轮发生碰撞事故,事故造成的灾难教训深刻。本文按照《1972年国际海上避碰规则》的相关条款及物理学等相关知识,着重从夜间驾驶台瞭望、驾驶台支持级船员瞭望等方面客观地对该碰撞事故做一剖析,并对高级值班驾驶员和参与瞭望的支持级值班人员的瞭望侧重点进行剖析,希冀航运界引以为鉴,维护航运安全。 展开更多
关键词 瞭望 夜视力 RADAR 船舶安全责任证书
在线阅读 免费下载
雷达脉冲编码理论方法及应用 预览
6
作者 王岩飞 李和平 韩松 《雷达学报》 CSCD 北大核心 2019年第1期1-16,共16页
该文提出了基于脉冲组合编码的雷达探测模式,建立了脉冲编码雷达的基本概念和理论模型。利用多脉冲组合及其时间、频率、相位参量的调制,实现脉冲信号在时间域、频率域、或者时频域结合的编码,为解决传统的脉冲及连续波雷达系统参数相... 该文提出了基于脉冲组合编码的雷达探测模式,建立了脉冲编码雷达的基本概念和理论模型。利用多脉冲组合及其时间、频率、相位参量的调制,实现脉冲信号在时间域、频率域、或者时频域结合的编码,为解决传统的脉冲及连续波雷达系统参数相互耦合约束、及其对雷达性能的限制问题,提供了基于多脉冲组合探测的新方法及理论基础。该文着重介绍了多脉冲组合探测的编码、目标信号恢复方法,以及结合研制的合成孔径雷达开展的编码方法、性能评估等实验研究。研究及实验表明,通过采用分频带脉冲编码方法,可使雷达信号采样率突破奈奎斯特采样定理限制,降低系统的实现难度,实验系统中实现了4.8 GHz采样率对5 GHz带宽信号的采样及无失真恢复,成像分辨率达到0.03×0.03 m;通过采用增加占空比的时域脉冲编码方法,实现了信噪比改善超过20 d B的大幅度提高;通过针对合成孔径雷达的成像特性进行2维编码,去除了信号模糊问题,实现了成像幅宽超过90 km等先进性能指标。理论及实验结果验证了脉冲编码方法在提高雷达核心性能方面的显著优势,为高性能雷达系统的实现建立了新的技术途径。 展开更多
关键词 雷达 合成孔径雷达 脉冲编码 多脉冲组合 连续脉冲 高重频变参量
在线阅读 免费下载
Modified version of three-component model-based decomposition for polarimetric SAR data 预览
7
作者 ZHANG Shuang YU Xiangchuan WANG Lu 《系统工程与电子技术:英文版》 SCIE EI CSCD 2019年第2期270-277,共8页
A new hybrid Freeman/eigenvalue decomposition based on the orientation angle compensation and the various extended volume models for polarimetric synthetic aperture radar(PolSAR) data are presented. There are three st... A new hybrid Freeman/eigenvalue decomposition based on the orientation angle compensation and the various extended volume models for polarimetric synthetic aperture radar(PolSAR) data are presented. There are three steps in the novel version of the three-component model-based decomposition.Firstly, two special unitary transform matrices are applied on the coherency matrix for deorientation to decrease the correlation between the co-polarized term and the cross-polarized term.Secondly, two new conditions are proposed to distinguish the manmade structures and the nature media after the orientation angle compensation. Finally, in order to adapt to the scattering properties of different media, five different volume scattering models are used to decompose the coherency matrix. These new conditions pre-resolves man-made structures, which is beneficial to the subsequent selection of a more suitable volume scattering model.Fully PolSAR data on San Francisco are used in the experiments to prove the efficiency of the proposed hybrid Freeman/eigenvalue decomposition. 展开更多
关键词 polarimetric synthetic aperture RADAR (PolSAR) RADAR POLARIMETRY hybrid Freeman/eigenvalue DECOMPOSITION scattering model
在线阅读 下载PDF
Current Status and Future Challenges of Weather Radar Polarimetry: Bridging the Gap between Radar Meteorology/Hydrology/Engineering and Numerical Weather Prediction 预览
8
作者 Guifu ZHANG Vivek N.MAHALE +25 位作者 Bryan J.PUTNAM Youcun QI Qing CAO Andrew D. BYRD Petar BUKOVCIC Dusan S.ZRNIC Jidong GAO Ming XUE Youngsun JUNG Heather D.REEVES Pamela L.HEINSELMAN Alexander RYZHKOV Robert D. PALMER Pengfei ZHANG Mark WEBER Greg M.MCFARQUHAR Berrien MOORE III Yan ZHANG Jian ZHANG J.VIVEKANANDAN Yasser AL-RASHID Richard L.ICE Daniel S.BERKOWITZ Chong-chi TONG Caleb FULTON Richard J. DOVIAK 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第6期571-588,共18页
After decades of research and development, the WSR-88 D(NEXRAD) network in the United States was upgraded with dual-polarization capability, providing polarimetric radar data(PRD) that have the potential to improve we... After decades of research and development, the WSR-88 D(NEXRAD) network in the United States was upgraded with dual-polarization capability, providing polarimetric radar data(PRD) that have the potential to improve weather observations,quantification, forecasting, and warnings. The weather radar networks in China and other countries are also being upgraded with dual-polarization capability. Now, with radar polarimetry technology having matured, and PRD available both nationally and globally, it is important to understand the current status and future challenges and opportunities. The potential impact of PRD has been limited by their oftentimes subjective and empirical use. More importantly, the community has not begun to regularly derive from PRD the state parameters, such as water mixing ratios and number concentrations, used in numerical weather prediction(NWP) models.In this review, we summarize the current status of weather radar polarimetry, discuss the issues and limitations of PRD usage, and explore potential approaches to more efficiently use PRD for quantitative precipitation estimation and forecasting based on statistical retrieval with physical constraints where prior information is used and observation error is included. This approach aligns the observation-based retrievals favored by the radar meteorology community with the model-based analysis of the NWP community. We also examine the challenges and opportunities of polarimetric phased array radar research and development for future weather observation. 展开更多
关键词 WEATHER RADAR POLARIMETRY RADAR METEOROLOGY numerical WEATHER prediction data assimilation MICROPHYSICS parameterization forward operator
在线阅读 下载PDF
机载雷达与RWR的兼容性能分析 预览
9
作者 王胜喜 《电子信息对抗技术》 2019年第5期45-48,71,共5页
针对复杂电磁环境下机载雷达与雷达告警接收机射频冲突问题,建立雷达辐射信号、天线隔离度和雷达告警接收机模型,详细分析雷达辐射信号对雷达告警接收机的干扰形成机理、干扰信号强度和干扰表现形式,并进行实例仿真。仿真结果表明机载... 针对复杂电磁环境下机载雷达与雷达告警接收机射频冲突问题,建立雷达辐射信号、天线隔离度和雷达告警接收机模型,详细分析雷达辐射信号对雷达告警接收机的干扰形成机理、干扰信号强度和干扰表现形式,并进行实例仿真。仿真结果表明机载雷达辐射信号对雷达告警接收机的干扰主要源自于雷达辐射主频信号,主频信号经空间耦合到雷达告警接收机超过其检测电平,造成雷达告警接收机产生虚假告警。 展开更多
关键词 雷达 雷达告警接收机 干扰
在线阅读 下载PDF
雷达用高深宽比金属铜微通道散热器的制作 预览
10
作者 李晓军 吕辉 +2 位作者 朱和卿 赵雯 杜立群 《航空制造技术》 2019年第1期95-100,共6页
基于电化学沉积技术在金属基底上制作了一种雷达用金属铜微通道散热器。针对使用高黏度SU-8胶制作高厚度胶膜时产生的胶厚不均匀问题,采用研磨抛光工艺处理未曝光的胶膜,提高了胶厚均匀性,成功解决了由于空气间隙大带来的尺寸偏差。提... 基于电化学沉积技术在金属基底上制作了一种雷达用金属铜微通道散热器。针对使用高黏度SU-8胶制作高厚度胶膜时产生的胶厚不均匀问题,采用研磨抛光工艺处理未曝光的胶膜,提高了胶厚均匀性,成功解决了由于空气间隙大带来的尺寸偏差。提出了一种在曝光显影前利用折射率计算胶厚的方法,并通过最小二乘法确定了SU-8胶对钠黄光的折射率。针对高深宽比SU–8胶膜因曝光剂量选择不合适导致制作失败的问题,通过光刻试验分析了曝光剂量对胶膜质量的影响,确定了最优的曝光剂量为640mJ/cm^2。在上述工艺和试验的基础上得到了质量良好的SU-8胶膜,并制作出了一种线宽50μm、高度大于250μm、深宽比大于5的金属铜微通道散热器,验证了该制作工艺的有效性。 展开更多
关键词 金属微通道 胶厚均匀性 胶厚测量 紫外光刻 雷达
在线阅读 免费下载
Impact of the Assimilation Frequency of Radar Data with the ARPS 3DVar and Cloud Analysis System on Forecasts of a Squall Line in Southern China 预览
11
作者 Yujie PAN Mingjun WANG 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第2期160-172,共13页
Assimilation configurations have significant impacts on analysis results and subsequent forecasts.A squall line system that occurred on 23 April 2007 over southern China was used to investigate the impacts of the data... Assimilation configurations have significant impacts on analysis results and subsequent forecasts.A squall line system that occurred on 23 April 2007 over southern China was used to investigate the impacts of the data assimilation frequency of radar data on analyses and forecasts.A three-dimensional variational system was used to assimilate radial velocity data,and a cloud analysis system was used for reflectivity assimilation with a 2-h assimilation window covering the initial stage of the squall line.Two operators of radar reflectivity for cloud analyses corresponding to single-and double-moment schemes were used.In this study,we examined the sensitivity of assimilation frequency using 10-,20-,30-,and 60-min assimilation intervals.The results showed that analysis fields were not consistent with model dynamics and microphysics in general;thus,model states,including dynamic and microphysical variables,required approximately 20 min to reach a new balance after data assimilation in all experiments.Moreover,a 20-min data assimilation interval generally produced better forecasts for both single-and double-moment schemes in terms of equitable threat and bias scores.We conclude that a higher data assimilation frequency can produce a more intense cold pool and rear inflow jets but does not necessarily lead to a better forecast. 展开更多
关键词 cloud analysis RADAR DATA ASSIMILATION DATA ASSIMILATION INTERVAL
在线阅读 下载PDF
Photonics-based radar with balanced I/Q de-chirping for interference-suppressed high-resolution detection and imaging
12
作者 Xingwei Ye Fangzheng Zhang +1 位作者 Yue Yang Shilong Pan 《光子学研究:英文版》 CSCD 2019年第3期265-272,共8页
Photonics-based radar with a photonic de-chirp receiver has the advantages of broadband operation and real-time signal processing, but it suffers from interference from image frequencies and other undesired frequency-... Photonics-based radar with a photonic de-chirp receiver has the advantages of broadband operation and real-time signal processing, but it suffers from interference from image frequencies and other undesired frequency-mixing components, due to single-channel real-valued photonic frequency mixing. In this paper, we propose a photonicsbased radar with a photonic frequency-doubling transmitter and a balanced in-phase and quadrature(I/Q)de-chirp receiver. This radar transmits broadband linearly frequency-modulated signals generated by photonic frequency doubling and performs I/Q de-chirping of the radar echoes based on a balanced photonic I/Q frequency mixer, which is realized by applying a 90° optical hybrid followed by balanced photodetectors. The proposed radar has a high range resolution because of the large operation bandwidth and achieves interference-free detection by suppressing the image frequencies and other undesired frequency-mixing components. In the experiment, a photonics-based K-band radar with a bandwidth of 8 GHz is demonstrated. The balanced I/Q de-chirping receiver achieves an image-rejection ratio of over 30 dB and successfully eliminates the interference due to the baseband envelope and the frequency mixing between radar echoes of different targets. In addition, the desired dechirped signal power is also enhanced with balanced detection. Based on the established photonics-based radar,inverse synthetic aperture radar imaging is also implemented, through which the advantages of the proposed radar are verified. 展开更多
关键词 Photonics-based RADAR I/Q de-chirping interference-suppressed HIGH-RESOLUTION detection
一种常规模式应答机错误应答S模式询问的分析 预览
13
作者 姚渊 《电子测试》 2019年第6期32-34,共3页
在空管监视领域,作为常规二次雷达的升级技术,S模式二次雷达可以克服常规二次雷达诸多弊端的同时,提供更丰富的目标信息,有效提高监视效率。但从常规模式向S模式转换的过程中,依然需要考虑运行层面的技术兼容性。本文分析了一种常规模... 在空管监视领域,作为常规二次雷达的升级技术,S模式二次雷达可以克服常规二次雷达诸多弊端的同时,提供更丰富的目标信息,有效提高监视效率。但从常规模式向S模式转换的过程中,依然需要考虑运行层面的技术兼容性。本文分析了一种常规模式应答机错误应答S模式询问,从而产生假目标的情况,并针对分析结果给出了相应的解决办法。 展开更多
关键词 监视 S模式 雷达 假目标
在线阅读 下载PDF
Mode decomposition methods and their application in ground penetrating radar data processing 预览
14
作者 ZHOU Weifan ZENG Zhaofa LI Jing 《世界地质:英文版》 2019年第3期199-208,共10页
Ground Penetrating Radar(GPR) method is a widely used method in engineering geophysical exploration at home and abroad. Compared with other geological exploration methods, the GPR method has the advantages of faster d... Ground Penetrating Radar(GPR) method is a widely used method in engineering geophysical exploration at home and abroad. Compared with other geological exploration methods, the GPR method has the advantages of faster detection, higher resolution, convenient operation and relatively low detection cost. With the wide application and continuous development of GPR methods, the processing and interpretation of GPR data is increasingly important. The authors introduce the development process and current situation of the modal decomposition method in processing GPR data, summarize the principles of four modal decomposition methods, and compare their advantages and disadvantages in ground penetrating radar data processing. The results show that when the quality of GPR data is good and the noise is small, Empirical Mode Decomposition(EMD) and Ensemble Empirical Mode Decomposition(EEMD) methods can be used for processing, whereas when the noise interference is large or the underground medium is complex, Complete Ensemble Empirical Mode Decomposition(CEEMD) and Variational Mode Decomposition(VMD) methods can be used for processing. The four modal decomposition methods have their own advantages and disadvantages in GPR data processing. At present, the processing of GPR data by CEEMD and VMD methods is the focus of research and discussion at home and abroad. 展开更多
关键词 Ground PENETRATING RADAR MODE DECOMPOSITION IMF mode-mixing
在线阅读 下载PDF
地质雷达对隧道衬砌无损检测中的实例应用分析 预览 被引量:1
15
作者 张国权 《黑龙江交通科技》 2019年第3期145-146,148共3页
地质雷达近年在隧道无损检测中发挥着重要作用,是隧道完工检测和日后养护检测使用的一个重要工具,本文通过采用地质雷达针对隧道无损检测实例应用分析,介绍地质雷达在隧道检测实际中的应用和如何使用地质雷达检测工程实际问题,针对一座... 地质雷达近年在隧道无损检测中发挥着重要作用,是隧道完工检测和日后养护检测使用的一个重要工具,本文通过采用地质雷达针对隧道无损检测实例应用分析,介绍地质雷达在隧道检测实际中的应用和如何使用地质雷达检测工程实际问题,针对一座问题隧道,分析检测数据,得出结论过成给广大工程检测人员参考。 展开更多
关键词 雷达 隧道检测 衬砌
在线阅读 下载PDF
雷达探测“蜂群”无人机作战效能评估 预览
16
作者 焦士俊 刘锐 +1 位作者 王冰切 刘剑豪 《舰船电子对抗》 2019年第1期38-41,共4页
针对雷达探测无人机“蜂群”定量评估难的问题,基于模糊层次分析法,构建了雷达探测效果评估模型,创新了雷达探测“蜂群”无人机评测流程,形成了一套简便可行的区分不同雷达对“蜂群”无人机探测效能的定量评估方法。
关键词 雷达 “蜂群”无人机 效能评估
在线阅读 下载PDF
基于GaN HEMTs的S波段大功率固态功放组件设计 预览
17
作者 彭恩超 张瑞 《中国电子科学研究院学报》 北大核心 2019年第2期206-211,共6页
介绍了一种基于氮化镓高电子迁移率晶体管(GaN HEMTs)的S波段大功率固态功放组件,详细阐述了组件的微波链路设计、热设计、BITE设计以及电源设计等设计中的关键性问题。测试结果表明,组件在450μs脉宽、15%占空比条件下输出峰值功率不小... 介绍了一种基于氮化镓高电子迁移率晶体管(GaN HEMTs)的S波段大功率固态功放组件,详细阐述了组件的微波链路设计、热设计、BITE设计以及电源设计等设计中的关键性问题。测试结果表明,组件在450μs脉宽、15%占空比条件下输出峰值功率不小于1.6 k W,效率达到40%。组件创新性地采用实时参数化的数字采样技术、激励/控制输入通道的冗余设计技术,适应高可靠雷达系统的健康管理对组件的智能化要求。 展开更多
关键词 功放组件 氮化镓 高电子迁移率晶体管 S波段 雷达 大功率
在线阅读 下载PDF
A high-efficiency, high harmonic rejection E-band SiGe HBT frequency tripler for high-resolution radar application
18
作者 Peigen ZHOU Pinpin YAN +2 位作者 Jixin CHEN Debin HOU Wei HONG 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第6期183-185,共3页
Dear editor,With the advances in silicon-based technologies,high performance, low-cost frequency-modulated continuous wave (FMCW) radar sensors enabling advanced driver-assistance convenience in vehicles have been dev... Dear editor,With the advances in silicon-based technologies,high performance, low-cost frequency-modulated continuous wave (FMCW) radar sensors enabling advanced driver-assistance convenience in vehicles have been developed extensively in recent years . 展开更多
关键词 FIGURE HIGH harmonic REJECTION E-band SiGe HBT frequency tripler for high-resolution radar APPLICATION A high-efficiency
Wave parameters retrieval for dual-polarization C-band synthetic aperture radar using a theoretical-based algorithm under cyclonic conditions 预览
19
作者 Yingying Ding Juncheng Zuo +5 位作者 Weizeng Shao Jian Shi Xinzhe Yuan Jian Sun Jiachen Hu Xiaofeng Li 《海洋学报:英文版》 SCIE CAS CSCD 2019年第5期21-31,共11页
Theoretical-based ocean wave retrieval algorithms are applied by inverting a synthetic aperture radar(SAR)intensity spectrum into a wave spectrum,that has been developed based on a SAR wave mapping mechanism.In our pr... Theoretical-based ocean wave retrieval algorithms are applied by inverting a synthetic aperture radar(SAR)intensity spectrum into a wave spectrum,that has been developed based on a SAR wave mapping mechanism.In our previous studies,it was shown that the wave retrieval algorithm,named the parameterized first-guess spectrum method(PFSM),works for C-band and X-band SAR at low to moderate sea states.In this work,we investigate the performance of the PFSM algorithm when it is applied for dual-polarization c-band sentinel-1(S-1)SAR acquired in extra wide-swath(EW)and interferometric wide-swath(IW)mode under cyclonic conditions.Strong winds are retrieved from six vertical-horizontal(VH)polarization S-1 SAR images using the c-band crosspolarization coupled-parameters ocean(C-3PO)model and then wave parameters are obtained from the image at the vertical-vertical(VV)polarization channel.significant wave height(SWH)and mean wave period(MWP)are compared with simulations from the WAVEWATCH-III(WW3)model.The validation shows a 0.69 m root mean square error(RMSE)of SWH with a–0.01 m bias and a 0.62 s RMSE of MWP with a–0.17 s bias.Although the PFSM algorithm relies on a good quality SAR spectrum,this study confirms the applicability for wave retrieval from an S-1 SAR image.Moreover,it is found that the retrieved results have less accuracy on the right sector of cyclone eyes where swell directly affects strong wind-sea,while the PFSM algorithm works well on the left and rear sectors of cyclone eyes where the interaction of wind-sea and swell is relatively poor. 展开更多
关键词 WAVE parameters synthetic APERTURE RADAR cyclonic condition
在线阅读 下载PDF
贵州三都“7.22”大风天气分析 预览
20
作者 赵杰 潘启学 黄桂东 《中低纬山地气象》 2019年第4期64-68,共5页
2018年7月22日三都县城出现局地短时大风,利用实况观测资料、多普勒雷达资料及FNL再分析资料对此次过程的气象要素变化、环境场、雷达、地形影响进行分析,发现:此次过程大形势不具备形成大风的条件,是午后热对流形成的雷暴大风;在大风... 2018年7月22日三都县城出现局地短时大风,利用实况观测资料、多普勒雷达资料及FNL再分析资料对此次过程的气象要素变化、环境场、雷达、地形影响进行分析,发现:此次过程大形势不具备形成大风的条件,是午后热对流形成的雷暴大风;在大风发生前5d三都县城气温维持35℃以上的高温天气,气压呈现降低的趋势,大风发生前1d三都与周围站点气压差开始增加;此次大风雷达回波生成于较高层次,在大风发生前出现了明显的反射率因子核心降低和中层径向辐合,有利于地面大风的出现,同时地形"狭管效应"与下垫面的影响使得河面上风力加大。 展开更多
关键词 雷暴大风 要素变化 雷达 地形
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部 意见反馈