一种近似用于高发射率城市地表热红外等效发射率的方向性变异核驱动模型及其不确定性分析

地表热红外发射率(8~14μm)的方向性变异为遥感地表温度的反演及应用引入了不确定性,这种问题在城市地表显得尤为突出.发展了一种近似用于高发射率城市地表热红外等效发射率的方向性变异(Urban Surface Emissivity Anisotropy,USEA)核驱动模型,并分析了具体应用时的不确定性,其中USEA用非垂直观测的发射率与垂直观测时的发射率之比定量表示.模型有两个基本假设:(1)白天,USEA具有热点效应,热点位置与太阳位置接近;(2)夜晚,USEA无明显热点效应,且主要与观测天顶角相关.该核驱动模型由各向同性核、多次散射核、以及温差核组成,其中各向同性核为常数1,多次散射核描...

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Published in红外与毫米波学报 Vol. 34; no. 1; pp. 66 - 73
Main Author 孙灏 陈云浩 占文凤 王萌杰 马伟
Format Journal Article
LanguageChinese
Published 南京大学江苏省地理信息技术重点实验室国际地球系统科学研究所,江苏南京210093%中国冶金地质总局矿产资源研究院,北京,100025 2015
北京师范大学地表过程与资源生态国家重点实验室资源学院,北京,100875%北京师范大学地表过程与资源生态国家重点实验室资源学院,北京100875
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ISSN1001-9014
DOI10.3724/SP.J.1010.2015.00066

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Summary:地表热红外发射率(8~14μm)的方向性变异为遥感地表温度的反演及应用引入了不确定性,这种问题在城市地表显得尤为突出.发展了一种近似用于高发射率城市地表热红外等效发射率的方向性变异(Urban Surface Emissivity Anisotropy,USEA)核驱动模型,并分析了具体应用时的不确定性,其中USEA用非垂直观测的发射率与垂直观测时的发射率之比定量表示.模型有两个基本假设:(1)白天,USEA具有热点效应,热点位置与太阳位置接近;(2)夜晚,USEA无明显热点效应,且主要与观测天顶角相关.该核驱动模型由各向同性核、多次散射核、以及温差核组成,其中各向同性核为常数1,多次散射核描述了USEA与观测天顶角的关系,温差核描述了USEA的热点效应.基于计算机模拟数据的模型评价结果表明,核驱动模型可以表达USEA的时空变化,但城市地表热惯量会导致模型的适用性降低.该核驱动模型在MODIS等传感器的方向性比辐射率数据上,具有一定的应用潜力.
Bibliography:As anisotropy of land surface thermal emissivity( 8 ~ 14 μm) reduces the accuracy of the remotely sensed land surface temperature( LST) and its application,which is more important for urban surface,a kernel model was suggested in this paper to describe the urban surface emissivity anisotropy( USEA). The USEA is estimated by the ratio between off-nadir and nadir observed emissivity. The kernel model has two basic assumptions:( 1) at daytime,USEA has apparent hot spot whose location approaches the sun's location;( 2) at nighttime,there is no apparent hot spot effect in USEA,but it has significant correlation with viewing zenith angle and weak correlation with azimuth angle. Three kernels named isotropic kernel,multi-scattering kernel,and temperature difference kernel constitute the kernel-based model,where the isotropic kernel is a constant equal to 1,the multi-scattering kernel describes the dependence on viewing zenith angle,and the temperature difference kernel describes the hot spot effect of USEA. Results,
ISSN:1001-9014
DOI:10.3724/SP.J.1010.2015.00066