光谱学与光谱分析
光譜學與光譜分析
광보학여광보분석
SPECTROSCOPY AND SPECTRAL ANALYSIS
2014年
10期
2873-2877
,共5页
高光谱%积雪性质%偏振度%多角度
高光譜%積雪性質%偏振度%多角度
고광보%적설성질%편진도%다각도
Hyperspectral%Snow properties%Degree of polarization%Multi-angle
积雪性质的变化会影响积雪的反射，从而遥感技术中可以利用反射信息的变化来确定积雪性质。由于反射过程中会产生偏振信息，在研究可见光近红外波段（350～2500 nm ）不同粒径大小积雪表面多角度反射特性的基础上，同时分析了粒径以及由干雪变成湿雪对积雪表面偏振反射特性的影响。通过野外测量结果表明，粒径大小对积雪表面偏振反射的影响在近红外波段1500 nm附近比较明显，表现为在前向散射方向，随着粒径的增加对应的偏振度变大；这是由于在该波段附近，积雪对光的吸收很强，随着粒径的增加，吸收会变大，探测器获取的光大部分为单次散射光，而单次散射光是引起偏振信息的主要来源；在研究过程中发现从干雪变成湿雪这一过程会使偏振信息增加，这是由于湿雪表面水膜的存在，将相邻的雪粒粘连在一起，相当于使积雪粒径变大，但是这种影响主要体现在近红外波段。综上所述，将多角度偏振信息与反射信息结合可以为反演积雪性质提供可靠的方法与理论基础。
積雪性質的變化會影響積雪的反射，從而遙感技術中可以利用反射信息的變化來確定積雪性質。由于反射過程中會產生偏振信息，在研究可見光近紅外波段（350～2500 nm ）不同粒徑大小積雪錶麵多角度反射特性的基礎上，同時分析瞭粒徑以及由榦雪變成濕雪對積雪錶麵偏振反射特性的影響。通過野外測量結果錶明，粒徑大小對積雪錶麵偏振反射的影響在近紅外波段1500 nm附近比較明顯，錶現為在前嚮散射方嚮，隨著粒徑的增加對應的偏振度變大；這是由于在該波段附近，積雪對光的吸收很彊，隨著粒徑的增加，吸收會變大，探測器穫取的光大部分為單次散射光，而單次散射光是引起偏振信息的主要來源；在研究過程中髮現從榦雪變成濕雪這一過程會使偏振信息增加，這是由于濕雪錶麵水膜的存在，將相鄰的雪粒粘連在一起，相噹于使積雪粒徑變大，但是這種影響主要體現在近紅外波段。綜上所述，將多角度偏振信息與反射信息結閤可以為反縯積雪性質提供可靠的方法與理論基礎。
적설성질적변화회영향적설적반사，종이요감기술중가이이용반사신식적변화래학정적설성질。유우반사과정중회산생편진신식，재연구가견광근홍외파단（350～2500 nm ）불동립경대소적설표면다각도반사특성적기출상，동시분석료립경이급유간설변성습설대적설표면편진반사특성적영향。통과야외측량결과표명，립경대소대적설표면편진반사적영향재근홍외파단1500 nm부근비교명현，표현위재전향산사방향，수착립경적증가대응적편진도변대；저시유우재해파단부근，적설대광적흡수흔강，수착립경적증가，흡수회변대，탐측기획취적광대부분위단차산사광，이단차산사광시인기편진신식적주요래원；재연구과정중발현종간설변성습설저일과정회사편진신식증가，저시유우습설표면수막적존재，장상린적설립점련재일기，상당우사적설립경변대，단시저충영향주요체현재근홍외파단。종상소술，장다각도편진신식여반사신식결합가이위반연적설성질제공가고적방법여이론기출。
In the context of remote sensing ,the reflectance of snow is a key factor for accurate inversion for snow properties , such as snow grain size ,albedo ,because of it is influenced by the change of snow properties .The polarized reflectance is a gen-eral phenomenon during the reflected progress in natural incident light .In this paper ,based on the correct measurements for the multiple-angle reflected property of snow field in visible and near infrared wavelength (from 350 to 2 500 nm) ,the influence of snow grain size and wet snow on the bidirectional polarized property of snow was measured and analyzed .Combining the results measured in the field and previous conclusions confirms that the relation between polarization and snow grain size is obvious in in-frared wavelength (at about 1 500 nm) ,which means the degree of polarization increasing with an increase of snow grain size in the forward scattering direction ,it is because the strong absorption of ice near 1 500 nm leads to the single scattering light con-tributes to the reflection information obtained by the sensor ;in other word ,the larger grain size ,the more absorption accompan-ying the larger polarization in forward scattering direction ;we can illustrate that the change from dry snow to wet snow also in-fluences the polarization property of snow ,because of the water on the surface of snow particle adheres the adjacent particles , that means the wet snow grain size is larger than the dry snow grain size .Therefore ,combining the multiple-angle polarization with reflectance will provide solid method and theoretical basis for inversion of snow properties .
