利用卫星高度计风速资料研究海面粗糙度     

周良明  郭佩芳  王爱方 《海洋通报(英文版)》2006,8(1):61-67

海面粗糙度对于海洋工程和海洋军事都非常重要,但对海面粗糙度的现场观测资料非常少, 这大大制约了对海面粗糙度的认识。利用 TOPEX 高度计风速资料实现了对海面粗糙度的反演,并利用 1993 年和1998 年两年的资料对西北太平洋海域的海面粗糙度进行了研究。  相似文献   

基于旋翼无人机雷达的船只目标成像与类型识别研究进展综述   总被引：1，自引：0，他引：1  

张晰  张杰  孟俊敏 《海洋科学》2020,44(6):141-147

载有成像雷达的旋翼无人机具有成本低廉、对起降条件要求低、飞行姿态灵活多样等优点，可以在热点区域进行普查、详查或长时间悬停凝视等多模式成像监测，现已成为海上船只目标监测识别的重要手段。本文分别从旋翼无人机雷达硬件系统、无人机载雷达动目标成像、船只目标类型识别和目标三维结构特征提取等四方面开展国内外研究进展综述。总结分析发现当前利用旋翼无人机雷达进行船只目标成像和类型识别，尚存在运动船只成像散焦、三维结构重建难度大、类型识别精度低等问题，迫切需要推动相关技术的发展。  相似文献   

The retrieval of the nonlinear random waves from the non-Gaussian characteristics of the sea surface elevation distribution     

Liu Xin''an  Huang Peiji 《海洋学报(英文版)》1993,12(4):499-510

In this paper, without recourse to the nonlinear dynamical equations of the waves, the nonlinear random waves are retrieved from the non-Gaussian characteristic of the sea surface elevation distribution. The question of coincidence of the nonlinear wave profile, spectrum and its distributions of maximum (or minimum) values of the sea surface elevation with results derived from some existing nonlinear theories is expounded under the narrow-band spectrum condition. Taking the shoaling sea wave as an example, the nonlinear random wave process and its spectrum in shallow water are retrieved from both the non-Gaussian characteristics of the sea surface elevation distribution in shallow water and the normal sea waves in deep water and compared with the values actually measured. Results show that they can coincide with the actually measured values quite well, thus, this can confirm that the method proposed in this paper is feasible.  相似文献   

青岛沿海一次降雪过程的多普勒雷达资料分析   总被引：1，自引：0，他引：1  

梁卫芳  刘珍芳  江敦双  孙正 《海洋湖沼通报》2006,(2):1-6

本文对2005年2月17日至18日青岛降雪过程的雷达资料进行了分析。多普勒雷达资料很好地揭示了青岛沿海成为本次过程区域降水中心的原因,除了有利的水汽输送,更重要的是青岛沿海出现了一个维持约半小时的中尺度气旋。在对雷达资料的风廓线资料分析时,发现系统中存在标注ND字符的异常原因。  相似文献   

基于SVM回归模型的SAR图像有效波高估测     

高东  刘永信  孟俊敏  贾永君  范陈清 《海洋学报(英文版)》2018,37(3):103-110

A new method for estimating significant wave height(SWH) from advanced synthetic aperture radar(ASAR) wave mode data based on a support vector machine(SVM) regression model is presented. The model is established based on a nonlinear relationship between σ0, the variance of the normalized SAR image, SAR image spectrum spectral decomposition parameters and ocean wave SWH. The feature parameters of the SAR images are the input parameters of the SVM regression model, and the SWH provided by the European Centre for Medium-range Weather Forecasts(ECMWF) is the output parameter. On the basis of ASAR matching data set, a particle swarm optimization(PSO) algorithm is used to optimize the input kernel parameters of the SVM regression model and to establish the SVM model. The SWH estimation results yielded by this model are compared with the ECMWF reanalysis data and the buoy data. The RMSE values of the SWH are 0.34 and 0.48 m, and the correlation coefficient is 0.94 and 0.81, respectively. The results show that the SVM regression model is an effective method for estimating the SWH from the SAR data. The advantage of this model is that SAR data may serve as an independent data source for retrieving the SWH, which can avoid the complicated solution process associated with wave spectra.  相似文献   

文本地理编码关键技术研究与分析     

闫梦宇  钟志农  景宁  吴烨 《测绘通报》2019,(5):72-76

随着互联网应用的发展，所产生的非结构化文本大多与地理位置相关联，因此，地理信息检索（GIR）成为当前GIS和IR领域研究的热点。文本地理编码是建立文本与地理位置坐标对应关系的过程，是实现GIR的基础。本文对文本地理编码涉及的地理实体识别、地理实体消歧、文本位置聚焦、区域语言建模等关键技术进行分类总结，提出了该领域未来研究工作和面临的挑战，为文本地理编码进一步相关研究提供新思路。  相似文献   

探地雷达在土地整治道路工程验收中的应用研究          下载免费PDF全文

宋文文  李新举 《山东国土资源》2018,34(3)

道路验收工作中,厚度、压实度等工程参数常常是验收工作中的重要指标,基于探地雷达的道路工程质量检测技术在土地整治项目区的道路验收中可以达到无损、快速和准确。研究采用pulse EKKO PRO 1000型探地雷达,使用剖面法对道路工程混凝土路面进行雷达探测,结合现场钻孔取心进行电磁波速度修正,经过校正、增益、背景去噪、反褶积等多项预处理,有效抑制噪声,提高分辨力,最后根据相应的电磁波传播速度值完成厚度分析工作,获得不同设计标准的道路工程面层与基层的厚度结构与路面的均匀度情况。结果表明,探地雷达对道路厚度结构探测最大相对误差不超过1.43%,标准差介于0.08~0.66之间,可见其准确度超越了传统方法,精度可靠;经处理后雷达图像清晰,可同步了解道路面层与基层的介质均匀度情况,其中面层厚度起伏不大,个别路段基层压实不充分,厚度不均。符合设计标准与验收要求,为土地整治道路工程的验收与质量评价工作提供有效的帮助。  相似文献   

Measuring snow ablation rates in alpine terrain with a mobile multioffset ground‐penetrating radar system          下载免费PDF全文

Nena Griessinger  Franziska Mohr  Tobias Jonas 《水文研究》2018,32(21):3272-3282

Ground‐penetrating radar (GPR) has become a promising technique in the field of snow hydrological research. It is commonly used to measure snow depth, density, and water equivalent over large distances or along gridded snow courses. Having built and tested a mobile lightweight set‐up, we demonstrate that GPR is capable of accurately measuring snow ablation rates in complex alpine terrain. Our set‐up was optimized for efficient measurements and consisted of a multioffset radar with four pairs of antennas mounted to a plastic sled, which was small enough to permit safe and convenient operations. Repeated measurements at intervals of 2 to 7 days were taken during the 2014/2015 winter season along 10 profiles of 50 to 200 m length within two valleys located in the eastern Swiss Alps. Resulting GPR‐based data of snow depth, density, and water equivalent, as well as their respective change over time, were in good agreement with concurrent manual measurements, in particular if accurate alignment between repeated overpasses could be achieved. Corresponding root‐mean‐square error (RMSE) values amounted to 4.2 cm for snow depth, 17 mm for snow water equivalent, and 22 kg/m³ for snow density, with similar RMSE values for corresponding differential data. With this performance, the presented radar set‐up has the potential to provide exciting new and extensive datasets to validate snowmelt models or to complement lidar‐based snow surveys.  相似文献   

基于VAP方法的多普勒雷达风场反演研究     

周鑫  刘艳 《成都信息工程学院学报》2007,22(3):338-342

采用VAP(Velocity Azimuth Processing)方法反演多普勒雷达风矢量场,在利用各个距离圈径向速度随方位角分布的廓线推算风向和风速的设计中,要求基数据速度资料中没有明显的脉动.介绍了在多普勒天气雷达风场反演设计中,直接将方格法的速度资料处理过程融入到方格法风场反演的过程中,利用距离方格内保持中尺度特性的特点,不改变原始资料的同时保证风场反演的正确性.  相似文献   

基于瞬时频率估计的InSAR相位解缠     

靳国旺  徐国华  余懋勋  谭雄  张宇驰 《测绘学院学报》2009,(1)

相位解缠是InSAR处理的关键步骤,解缠结果的可靠性和稳定性影响着InSAR测量的性能。从干涉条纹频率与相位解缠结果之间的内在联系出发,推导了干涉条纹频率与干涉复数值之间的严密关系式,设计了基于瞬时频率估计的相位解缠方法,采用多套干涉数据获取的干涉图进行了相位解缠实验,验证了基于瞬时频率估计方法进行相位解缠的可行性。  相似文献