radar backscatter meaning in Chinese
雷达后向散射
Examples
- We studied radar backscattering models of ocean surface and modulation mechanism of sar signal . and the research focuses on the composite surface backscattering model and velocity bunching modulation mechanics . based on these theories , we built up an sar imaging model pertained to ocean waves
研究了海面的电磁波后向散射模型和海浪对sar信号的调制机理，其中，重点研究了复合表面模型和速度聚束调制机理，在此基础上建立了适合于海面的sar成像模型。 - For parameter a , there is a close relationship exist between a ( 9 , sr ) in two different radar incident angle that can be expressed as : with considering the effects of soil texture , we get the final expression of the inversion model : where mv ( t1 ) , mv ( t2 ) is volumetric soil moisture content in two different temp , c , d is soil type related parameters , and v ( t1 ) , s ( t2 ) is coresponding bare soil radar backscattering coefficients . inversion results show that for the c band hh polarized radarsat scansar data with a range of incidence angle from 20 to 40 , the soil moisture change value can be derived with an acceptable accuracy using the above model . the temporal and spatial soil moisture change patterns are associated with rainfall and vegetation cover , as well as the soil hydraulic characteristics
利用最新发展的电磁波散射模型研究了不同植被覆盖地表雷达波对地表土壤水分的敏感性，建立了半经验植被雷达后向散射模型; 2 ) .研究发现在农作物等矮小植被覆盖地表，植被层直接后向散射与植被类型相关，且在植被生长期，雷达后向散射系数对植被含水量的敏感性要高于对植被高度变化的敏感性; 3 ) .解决了单参数雷达地表土壤水分反演问题中，雷达入射角和地表粗糙度的影响这一难点问题; 4 ) .利用土壤介电模型校正了不同土壤类型对反演地表土壤体积含水量的影响; 5 ) .在以上成果基础上，建立了完整的单参数雷达地表土壤水分变化探测反演算法，经地表验证，模型反演地表土壤水分变化值的精度为rmse = 0 - There is an urgent need for the polarimetric synthetic aperture radar ( sar ) data to be calibrated , so that the quantitative relationships between radar backscatter and geophysical parameters can be properly established , along with the development of international polarimetric sar technology and more and more in - depth study and application of polarimetric sar data . up to now a lot of polarimetric sar calibration methods have been developed . some of them have been used in several applied sar systems and the calibration results are satisfying
随着国际上多极化合成孔径雷达技术的发展以及雷达图像应用的门益广泛和深入，定量化应用的要求逐渐变得迫切，因而极化定标技术得到了广泛深入的研究，并且涌现了大量的各有特色的算法，有些也已经投入具体系统的实际应用中并获得了令人满意的结果。 - Main conclusions drawn from the analyses of calculating results are as follows : ( 1 ) the microwave absorption of atmosphere gas have obvious attenuation at the wavelengths for cloud detection , thereinto , the water attenuation effect changes greatly , so the 94ghz cloud detecting radar should have water vapor attenuation correction scheme . ( 2 ) when 37ghz and 94ghz radars detect clouds , the difference between the atmosphere and cloud attenuation and the large variety of radar reflectivity conduce the intension of the radar backscatter signals change . ( 3 ) for the thin cloud layer and low water content of cloud , 37 - ghz radar backscatter signals are not as good as 94 - ghz radar , that is to say that the 94ghz radar has better capability in thin clouds detection
本工作得出如下结论： ( 1 )大气气体的微波吸收在测云波段产生明显的衰减，其中水汽衰减效应变化很大；即将上天的空间94ghz测云雷达必须有水汽衰减订正方案； ( 2 ) 37ghz和94ghz雷达测云，由于大气和云衰减不同和雷达反射率的很大差异，导致雷达回波信号强弱不同； ( 3 )对云层较薄、含水量较少的云，在不计雷达参数的情况下， 37ghz雷达回波信号不如94ghz测云雷达，也就是说94ghz对薄云有更强的探测能力；对云层较厚、含水量大的云，由于强衰减的作用， 94ghz雷达回波信号小于37ghz雷达； ( 4 )从大气衰减的不利因素方面考虑，空间94ghz雷达测高层薄云的效果最好；测低层薄云时需要考虑气体衰减订正；因浓厚云的强衰减作用，探测其中下部的能力大大减弱，不仅要进行衰减订正，而且要借助其他信息来反演整个云层的含水量垂直分布； （ 5 ）为了获得从极薄到极浓厚云的垂直分布探测能力，未来测云雷达系统最好采用双波长甚至三波长（如94 、 37和13ghz ） 。 - 2 ) radar incidence angle and surface roughness correction : to make radar incidence correction and eliminate the surface roughness effects , a wide range of surface parameters ( soil moisture , surface rms height , correlation length , incidence angle ) was input to the ibm model to simulate the effect of surface roughness and radar incidence angle on the sensitivity of soil moisture to the radar backscattering coefficient . a simple model was established to simulate the effects of incidence angle and surface roughness . 3 ) establishment of soil moisture change inversion model : according to a modified ibm model simulation results , the bare surface backscattering coefficients can be expressed as a funtion of the dielectric component for a given surface roughness when the surface slope greater than 2 . 0 , which is valid for most nature surface : in above equation , r0 is the surface reflectivity at normal incidence
本研究中，首先利用基于微波辐射传输方程的微波植被模型和积分方程( iem )模型模拟了各种地表土壤水分含量情况下，植被覆盖、地表粗糙度(包括地表均方根高度和相关长度) 、雷达入射角对c波段(频率4 . 7ghz )水平极化( hh )雷达后向散射系数的影响，在此基础上，建立模型消除了植被覆盖、地表粗糙度、及雷达入射角对雷达后向散射的影响，利用多时相50m分辨率radarsatscansar雷达后向散射系数图像反演得到了地表土壤水分变化模式信息。