利用后向散射特性从高分辨率SAR影像中提取建筑物高度     

刘康  Timo Balz  廖明生 《武汉大学学报(信息科学版)》2012,37(7):806-809

研究了一种基于雷达后向散射特性,从单张星载高分辨率SAR影像提取建筑物高度的方法。该方法通过检测建筑物二次散射强度,同时获取目标方位角、入射角等参数以及相关介质特性等信息,根据后向散射几何光学模型估算建筑物高度。实验验证了对于相当一部分典型建筑物都能够获得较为理想的高程估计值,进而证明了该方法提取建筑物高度的可行性和有效性。  相似文献   

湖冰厚度遥感反演进展与展望     

李兴东  龙笛  黄琦  赵凡玉  刘廷玺 《遥感学报》2022,26(7):1289-1301

湖冰是对气候变化十分敏感的冰冻圈水文变量,起到调节区域气候和湖泊生态系统的作用,并作为一种自然资源服务于冰上生产生活。湖冰覆盖和湖冰厚度是研究湖冰过程的关键变量,目前大多数湖冰研究集中在湖冰覆盖领域,湖冰厚度领域由于缺乏实测资料和专门的遥感观测平台还存在诸多空白,大量缺资料地区湖冰厚度仍处于未知状态,亟待方法和数据上的突破与创新。本文综述了近20年国内外湖冰厚度遥感反演领域的进展,介绍了各类反演方法的原理机理及主要优缺点,其中被动微波遥感方法具有良好的时间分辨率但空间分辨率较粗,难以覆盖中小型湖泊;基于SAR影像的主动微波方法空间分辨率较高但物理机制复杂,可靠性有待进一步验证;基于测高雷达的主动微波方法观测时段较长,物理机制明确,易于拓展到无实测资料湖泊,但空间覆盖相对有限;热红外遥感方法时空分辨率较好,但容易受云和湖冰表面积雪的影响,反演精度和可靠性有待提升。在此基础上,本文分析湖冰厚度遥感反演领域面临的主要挑战和发展方向包括：（1）厘清湖冰表面积雪相关的物理过程;（2）实现大范围实测冰厚和遥感资料的集成;（3）实现多源遥感冰厚反演方法的交叉融合。  相似文献   

Seafloor sediment classification based on multibeam sonar data   总被引：1，自引：1，他引：0  

ZHOUXinghua CHENYongqi 《地球空间信息科学学报》2004,7(4):290-296

The multibeam sonars can provide hydrographic quality depth data as well as hold the potential to provide calibrated measurements of the seafloor acoustic backscattering strength. There has been much interest in utilizing backscatters and images from multibeam sonar for seabed type identification and most results are obtained. This paper has presented a focused review of several main methods and recent developments of seafloor classification utilizing multibeam sonar data or/and images. These are including the power spectral analysis methods, the texture analysis, traditional Bayesian classification theory and the most active neural network approaches.  相似文献   

Effects of fish school structures on acoustic scattering     

Alvarez  A.; Ye  Z. 《ICES Journal of Marine Science》1999,56(3):361-369

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ADCP对悬浮沉积物浓度的测量及其误差分析研究   总被引：6，自引：0，他引：6  

兰志刚  龚德俊  李思忍  徐永平  秦枫  姜静波 《海洋科学》2004,28(10):20-23

为实时、连续地测量海水中悬浮沉积物,利用声学多普勒海流剖面仪(ADCP),可以在测流的同时,测量海洋悬浮沉积物浓度。描述了利用后散射强度,估计悬浮沉积物浓度的原理。在现场测试中,利用采水器采集水样,通过水样分析并结合声信号的衰减特征对AI)CP的测量结果进行修正。作者还结合现场测试结果,对这一测量方法的精度进行了分析。现场实验表明,经公式校正后,ADCP测得的后散射强度与实测水样所获得的悬浮沉积物浓度之间有很好的相关性,相关系数达0．88,由此证明,此测量方法具有很好的实用价值和应用前景。  相似文献   

富营养化湖泊典型水华蓝藻的固有光学特性   总被引：2，自引：2，他引：0  

张壹萱  张玉超  周雯  张民  马荣华 《湖泊科学》2018,30(6):1681-1692

固有光学特性是水体光学特性的重要内容,掌握富营养化湖泊水体内典型水华蓝藻的固有光学特性,是开展不同水华蓝藻遥感识别的理论基础.利用AC-S吸收衰减仪、BB9后向散射仪,通过实验室纯藻培养,研究微囊藻（Microcystis）、鱼腥藻（Dolichospermum）和束丝藻（Aphanizomenon）3种典型水华蓝藻的固有光学特性,并探讨色素浓度、色素占比以及藻类等效粒径对不同水华蓝藻固有光学特性的影响.结果表明,3种典型水华蓝藻的吸收光谱曲线均具有440、620和675 nm吸收峰,微囊藻620和675 nm的比吸收系数最大,鱼腥藻440 nm处的比吸收系数最大;束丝藻单位色素浓度的散射和后向散射能力最高,鱼腥藻次之,微囊藻最低;固有光学特性影响因子分析表明,色素浓度和藻蓝素占比是影响3种水华蓝藻固有光学特性的主要因素.3种蓝藻的吸收系数、散射系数以及鱼腥藻、束丝藻的后向散射系数均随着色素浓度（叶绿素a或藻蓝素）的增加而增大;当蓝藻中藻蓝素占比增加时,3种蓝藻的单位色素浓度的后向散射系数逐渐下降;而藻细胞粒径与固有光学特性之间并未表现出很好的相关性.因此,3种水华蓝藻单位色素浓度的固有光学特性将为典型水华蓝藻的遥感识别提供重要的理论基础和数据支持.  相似文献   

A 1-D model of the formation and evolution of Polar Stratospheric Clouds     

G. Panegrossi  D. Fuà  G. Fiocco 《Journal of Atmospheric Chemistry》1996,23(1):5-35

A 1-D model of the formation and seasonal evolution of Polar Stratospheric Clouds (PSCs) is described. The model considers PSCs of types 1 and 2 in the vertical range from 8 to 30 km and utilizes real temperature data. The micro-physical processes included in the model are the heterogeneous nucleation and condensation (or evaporation), while sedimentation, gas diffusion and vertical wind velocity are the processes responsible for transport. Model simulations have been compared with PSC data obtained by lidar at the South Pole: results for the winter 1990 are discussed. The different contribution of type 1 and type 2 PSCs to the measured backscattering coefficient has been evidenced. In the simulations, layers of NAT particles form when low values of the backscattering coefficient are measured; similarly, ice particles form when sharper and rapidly changeable structures with higher values of the backscattering coefficient are observed. Significant results on the condensation and depletion of HNO₃ and H₂O are presented. Water vapor profiles measured during winter 1990 are reproduced quite well.  相似文献   

Distribution and spatial structure of pelagic fish schools in relation to the nature of the seabed in the Sicily Straits (Central Mediterranean)     

Marta D'Elia  Bernardo Patti  Attilio Sulli  Giorgio Tranchida  Angelo Bonanno  Gualtiero Basilone  Giovanni Giacalone  Ignazio Fontana  Simona Genovese  Cástor Guisande  & Salvatore Mazzola 《Marine Ecology》2009,30(S1):151-160

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基于SAR的海上溢油监测最佳探测参数分析   总被引：8，自引：5，他引：3       下载免费PDF全文

邹亚荣  梁超  陈江麟  崔松雪  郎姝燕 《海洋学报》2011,33(1):36-44

基于SAR数据,在后向散射系数计算的基础上,从波段、极化方式、入射角等方面开展了海上溢油监测参数分析,结果表明:基于SAR的海上溢油监测,从波段分析,X波段与C波段较L波段更适合监测海上溢油;从极化方式分析,VV极化较HH,HV极化更适合监测海上溢油;从入射角分析,在计算溢油与海水临界值时,经多次实验,位于远入射角的疑...  相似文献   

A multi-frequency Acoustic Concentration and Velocity Profiler (ACVP) for boundary layer measurements of fine-scale flow and sediment transport processes     

David Hurther  Peter D. Thorne  Mickaël Bricault  Ulrich Lemmin  Jean-Marc Barnoud 《Coastal Engineering》2011

The use of acoustics to measure sediment transport boundary layer processes has gained increasing acceptance over the past two decades. This has occurred through the development of increasingly sophisticated measuring systems and theoretical developments, which have enabled flow and suspended sediment parameters to be obtained from acoustic data with a high degree of accuracy. Until relatively recently, separate acoustic systems were used to measure flow and suspended sediment concentration. Over the past few years, however, the technology has become sufficiently advanced so that flow and sediment measurements can be integrated into a single system. This integration provides, quasi-instantaneous, non-intrusive, co-located, high temporal-spatial resolution measurements of benthic flow and sediment processes. Here the development of such an instrument, the Acoustic Concentration and Velocity Profiler (ACVP) is described. The theory underpinning its application is outlined, new approaches to velocity de-aliasing and suspended sediment inversion instabilities using multi-frequency capabilities are presented and the application of the system to sediment transport processes over a sandy ripple bed is illustrated. The observations clearly show the value of such instrumentation for studying the dynamical interaction between the bed, the flow and the sediments at and within the bottom boundary layer.  相似文献