森林植被衰减系数极化特征研究

采用室内宽带极化测量系统获得了小场景森林植被3～10 GHz高精度多极化的频域数据,通过时域响应定量推导了极化衰减差异与回波电平的数学关系,并结合植被的形态特征分析了极化衰减特征随频率的变化规律。结果表明通过不同极化的衰减系数差异能够刻画森林植被结构的形态分布特征。当频率较低时,森林植被的结构分布体现有向性,随着频率的升高,主要的回波来自于冠层,植被结构呈现随机性分布特点。

Exploring Attenuation Coefficients of Forest Vegetation with Broadband Backscattering Measurement System

The introduction of the full paper reviews a number of papers in the open literature and then proposes using the indoor broadband backscattering measurement system to obtain the accurate and multi-polarized 3～10 GHz frequency-domain data of a small-scenario forest.Sections 1,2 and 3 explain our exploration.Their core consists of:(1) we establish the model of attenuation coefficient of forest vegetation and quantitatively derive the mathematical relations between the polarized attenuation coefficients of the forest vegetation and those of its echo by using time-domain analysis;(2) we establish a broadband backscattering measurement system to analyze the variation of polarized attenuation characteristics with frequency by means of the morphological characteristics of forest vegetation.The experimental results,given in Figs 3 and 4,and their analysis show preliminarily that:(1) the various polarized attenuation coefficients can describe the morphological characteristics of forest vegetation;(2) when the frequency of the broadband backscattering measurement system is low,the structural distribution of forest vegetation has its original orientation;as the frequency increases,the echo of forest vegetation mainly comes from canopy and its structure has random distribution.