地表粗糙度 meaning in English
surface roughness
Examples
- The earth surface rough degree after mechanical cultivation is important to reduce erosion
机械耕翻增加了地表粗糙度，对减风降蚀起了重要作用。 - This technique is mainly involved two steps : 1 ) vegetation effects correction : we used ndvi ( normalized difference vegetation index ) derived from tm and avhrr measurements for spatial and temporal variations of vegetation covers at different scales
但由于电磁波与地表相互作用的复杂性，雷达后向散射系数除受地表介电常数(土壤水分)影响外，还受到地表粗糙度、土壤类型、植被覆盖以及雷达入射角、频率、极化等多种因素的影响。 - Based on wind speed observation record with drawback , it is proved that the exponent expressing terrain roughness can be calculated according the monthly maximum wind speed records at various height levels . wind characteristics of bridge site are determined by statistical method
针对桥址区风速观测记录的特点，证明了利用不同高度处月最大风速记录推算地表粗糙度影响系数的可行性，并对通过最小二乘拟合得到的地表粗糙度影响系数进行统计分析，最终确定桥址区风特性。 - 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 - 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。