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Forward a spatio-temporal trend surface for long-term groundmeasured albedo upscaling over heterogeneous land surface

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International Journal of Digital Earth 2018年第5期11卷 470-484页

作者： Xiaodan Wu jianguang wen Qing Xiao Dongqin You Qiang Liu Xingwen Lin State Key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingPeople’s Republic of China College of Resources and Environment University of Chinese Academy of SciencesBeijingPeople’s Republic of China Joint Center for Global Change Studies BeijingPeople’s Republic of China College of Global Change and Earth System Science Beijing Normal UniversityBeijingPeople’s Republic of China

Upscaling ground albedo is challenged by the serious discrepancy between the heterogeneity of land surfaces and the small number of ground-based *** ground-based measurements cannot provide sufficient information on the characteristics of surface albedo at the scale of coarse pixels over heterogeneous land *** method of overcoming this problem is to introduce high-resolution albedo imagery as ancillary information for ***,due to the low frequency of updating of high-resolution albedo maps,upscaling time series of ground-based albedo measurements is *** paper proposes a method that is based on the idea of conceptual universal scaling methodology for establishing a spatiotemporal trend surface using very few high-resolution images and time series of ground-based measurements for spatial-temporal upscaling of *** construction of the spatiotemporal trend surface incorporates the spatial information provided by auxiliary remote sensing images and the temporal information provided by long time series of ground *** approach was illustrated by upscaling ground-based fine-scale albedo measurements to a coarse scale over the core study area in *** results indicate that this method can characterize the spatiotemporal variations in surface albedo well,and the overall correlation coefficient was 0.702 during the study period.

关键词： Trend surface upscaling spatiotemporal heterogeneous albedo

Evaluation of several recently developed sampling strategies within the coarse pixel scale for validation of coarse-resolution satellite albedo products

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International Journal of Digital Earth 2022年第1期15卷 2319-2334页

作者： Rongqi Tang Xiaodan Wu Jingping Wang Qicheng Zeng Zheng Li jianguang wen College of Earth and Environmental Sciences Lanzhou UniversityLanzhouPeople’s Republic of China State Key Laboratory of Remote Sensing Science Aerospace Information Research InstituteChinese Academy of SciencesBeijingPeople’s Republic of China University of Chinese Academy of Sciences BeijingPeople’s Republic of China

Due to the spatial heterogeneity and the spatial scale mismatch between in situ and satellite-based measurements,optimal ground sampling should be made to increase the representativeness of in situ observations. Therefore,many ground sampling strategies have been proposed,but their performance within the coarse pixel has not been evaluated. Hence,this study evaluated four typical methods regarding their ability to obtain pixel scale ground ‘truth’. Random combination (RC) performs best,with the always fewest samples to satisfy representativeness errors (REs) of 3% in the case of a small number of samples. When the goal of sampling is to obtain in situ measurements with REs close to 0 at the expense of increasing the number of samples,cumulative representativeness sampling (CRS) is more effective than RC in less heterogeneous areas. Geo-statistical model-based sampling (GSS) does not work well because the number of samples within the coarse pixel scale cannot support a robust semi-variogram model. Stratified sampling (SS) is highly dependent on spatial heterogeneity and does not work well in the case of small sample sizes. This study gives important guidance for ground sample deployment within the coarse pixel for validation of coarse-resolution satellite albedo products over a heterogeneous surface.

关键词： Sampling spatial heterogeneity validation representative observations coarse-pixel scale

Upscaling in situ albedo for validation of coarse scale albedo product over heterogeneous surfaces

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International Journal of Digital Earth 2017年第6期10卷 604-622页

作者： Xiaodan Wu Qing Xiao jianguang wen Qiang Liu Dongqin You Baocheng Dou Yong Tang State Key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingPeople’s Republicof China College of Resourcesand Environment University of Chinese Academy of SciencesBeijingPeople’s Republic of China Joint Center for Global Change Studies BeijingPeople’s Republic of China College of Global Change and Earth System Science Beijing Normal UniversityBeijingPeople’s Republic of China

One of the essential steps for satellite albedo validation is upscaling in situ measurements to corresponding pixel scale over relatively heterogeneous land *** the multi-scale validation strategy is applicable for heterogeneous surfaces,the calibration of the high-resolution imagery during upscaling process is never perfect,and thus the upscaling results suffer from *** regression-kriging(RK)technique can compensate the calibration part by applying kriging to upscale residuals and produce more accurate upscaling *** this paper,in situ measurements and high spatial resolution albedo imagery combined with RK technique was *** method is illustrated by upscaling surface albedo from in situ measurements scale to the coarse pixel scale in the core experimental area of HiWATER,where 17 WSN nodes were deployed at heterogeneous *** upscaling results of this method were compared with the upscaling results from multi-scale *** results show that the upscaling method based on in situ measurements and high-resolution imagery combined with RK technique can capture the spatial characteristics of surface albedo ***,an attempt was made to expand this method in time ***,a preliminary validation of the Moderate Resolution Imaging Spectroradiometer albedo product was performed as the tentative application.

关键词： Upscaling albedo heterogeneous validation in situ multi-scale

A review of the estimation of downward surface shortwave radiation based on satellite data:Methods, progress and problems

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Science China Earth Sciences 2020年第6期63卷 774-789页

作者： Husi LETU Jiancheng SHI Ming LI Tianxing WANG Huazhe SHANG Yonghui LEI Dabin JI jianguang wen Kun YANG Liangfu CHEN Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100010China Deparment of Earth System Science Tsinghua UniversityBeijing 100049China

The estimation of downward surface shortwave radiation(DSSR)is important for the Earth’s energy budget and climate change *** review was organised from the perspectives of satellite sensors,algorithms and future trends,retrospects and summaries of the satellite-based retrieval methods of DSSR that have been developed over the past 10 *** shortwave radiation reaching the Earth’s surface is affected by both atmospheric and land surface *** recent years,studies have given detailed considerations to the factors which affect *** is important to improve the retrieval accuracy of cloud microphysical parameters and aerosols and to reduce the uncertainties caused by complex topographies and high-albedo surfaces(such as snow-covered areas)on DSSR *** review classified DSSR retrieval methods into four categories:empirical,parameterisation,look-up table and machine-learning methods,and evaluated their advantages,disadvantages and *** efforts are needed to improve the calculation accuracy of atmospheric parameters such as cloud,haze,water vapor and other land surface parameters such as albedo of complex terrain and bright surface,organically combine machine learning and other methods,use the new-generation geostationary satellite and polar orbit satellite data to produce highresolution DSSR products,and promote the application of radiation products in hydrological and climate models.

关键词： Downward surface shortwave radiation Satellite remote sensing Cloud optical property Terrain correction

Multi-scale validation strategy for satellite albedo products and its uncertainty analysis

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Science China Earth Sciences 2015年第1期58卷 573-588页

作者： PENG JingJing LIU Qiang wen jianguang LIU QinHuo TANG Yong WANG LiZhao DOU BaoCheng YOU DongQin SUN ChangKui ZHAO XiaoJie FENG YouBin SHI Jian State Key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences College of Global Change and Earth System Science Beijing Normal University

Coarse-resolution satellite albedo products are important for climate change and energy balance research because of their capability to characterize the spatiotemporal patterns of land surface parameters at both the regional and global scales. The accuracy of coarse-resolution products is usually assessed via comparison with in situ measurements. The key issue in the comparison of remote sensing observations with in situ measurements is scaling and uncertainty. This paper presents a strategy for validating 1-km-resolution remote sensing albedo products using field measurements and high-resolution remote sensing observations. Field measurements were collected to calibrate the high-resolution(30 m) albedo products derived from HJ-1a/b images. Then, the calibrated high-resolution albedo maps were resampled(i.e., upscaled) to assess the accuracy of the coarse-resolution albedo products. The samples of field measurements and high-resolution pixels are based on an uncertainty analysis. Two types of coarse-resolution albedo datasets, from global land surface satellite(GLASS) and moderate-resolution imaging spectroradiometer(MODIS), are validated over the middle reaches of the Heihe River in China. The results indicate that the upscaled HJ(Huan Jing means environment in Chinese and this refers to a satellite constellation designed for environment and disaster monitoring by China) albedo, which was calibrated using field measurements, can provide accurate reference values for validating coarse-resolution satellite albedo products. However, the uncertainties in the upscaled HJ albedo should be estimated, and pixels with large uncertainties should be excluded from the validation process.

关键词： MCD43B3 GLASS02 uncertainty analysis validation remote sensing albedo

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A web-based land surface remote sensing products validation system (LAPVAS): application to albedo product

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International Journal of Digital Earth 2018年第3期11卷 308-328页

作者： Xingwen Lin jianguang wen Yong Tang Mingguo Ma Dongqin You Baocheng Dou Xiaodan Wu Xiaobo Zhu Qing Xiao Qinghuo Liu State Key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingPeople’s Republic of China University of Chinese Academy of Sciences BeijingPeople’s Republic of China Joint Center for Global Change Studies BeijingPeople’s Republic of China School of Geographical Sciences Southwest UniversityChongqingPeople’s Republic of China College of Global Change and Earth System Science Beijing Normal UniversityBeijingPeople’s Republic of China

Quantitative remote sensing product(QRSP)validation is a complex process to assess the accuracy and uncertainty independently using reference data with multiple land cover types and long-time series.A web-based system named as LAnd surface remote sensing Product VAlidation system(LAPVAS)is described in this paper,which is used to implement the QRSPs validation process *** LAPAVS has two subsystems,the Validation Databases Subsystem and the Accuracy Evaluation *** functions have been implemented by the two subsystems for a comprehensive QRSP validation:(1)a standardized processing of reference data and storage of these data in validation databases;(2)a consistent and comprehensive validation procedure to assess the QRSPs’accuracy and uncertainty;and(3)a visual process customization tool with which the users can register new validation data,host new reference data,and readjust the validation workflows for the QRSP accuracy *** LAPVAS,more than 100 GB of reference data warehoused in validation databases for 13 types of QRSPs’*** of the key QRSPs,land surface albedo,is selected as an example to illustrate the application of *** is demonstrated that the LAPVAS has a good performance in the land surface remote sensing product validation.

关键词： Remote sensing validation system LAPVAS uncertainty information albedo

异质性地表反照率遥感产品真实性检验研究现状及挑战

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遥感学报 2019年第1期23卷 11-23页

作者：吴小丹肖青闻建光游冬琴兰州大学资源环境学院兰州730000 中国科学院遥感与数字地球研究所北京100101 中国科学院大学北京100049

地表反照率直接决定了地表能够吸收到的太阳辐射能量,是研究气候变化、能量平衡的一个关键参数。遥感为大尺度、连续获取地表反照率提供了一种有效的观测手段。但遥感数据本身的精度限制和反演模型的不确定性,使基于卫星数据反演的反照... 详细信息

地表反照率直接决定了地表能够吸收到的太阳辐射能量,是研究气候变化、能量平衡的一个关键参数。遥感为大尺度、连续获取地表反照率提供了一种有效的观测手段。但遥感数据本身的精度限制和反演模型的不确定性,使基于卫星数据反演的反照率产品存在误差,而这种误差的存在又会影响产品的进一步应用。正确的认识这种误差有助于提高产品的应用精度,深化其应用的深度和广度。真实性检验就是正确认识卫星反照率产品准确性、稳定性的重要手段,它是卫星产品从生产到应用的桥梁。虽然目前已经开展了大量的真实性检验工作,但即使是针对同一种卫星产品,真实性检验的结果往往并不一致。其根本原因在于验证中所采用的参考值能不能够准确地代表卫星像元尺度的地面真值。地面观测和卫星产品像元之间巨大的尺度差异以及广泛分布的地表异质性,使地面观测并不能直接作为像元尺度真值与卫星产品进行简单的对比。因此真实性检验过程并不是直接的,而是需要经过一系列严格、独立的过程得到像元尺度真值后与产品在一定的空间和时间范围内进行对比。针对目前真实性检验结果准确性和可信度不高等问题,本文尝试从地面实测数据、尺度转换、验证方式、评价方法及验证中存在的问题等几个方面来论述反照率产品的真实性检验现状及挑战。

关键词：真实性检验地表异质性尺度反照率

高分卫星数据应用产品分级与共性产品体系构建研究

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遥感学报 2023年第3期27卷 563-572页

作者：廖楚江赵坚邢进闻建光柳钦火国家航天局对地观测与数据中心北京100101 中国科学院空天信息创新研究院遥感科学国家重点实验室北京100101

高分辨率对地观测系统重大专项(以下简称“高分专项”)部署建设国家真实性检验系统,目的是形成对高分共性产品进行真实性检验的能力,打造共性产品批量化生产能力,整体提高中国的高分遥感定量化应用水平。此项工作中,如何界定共性产品、... 详细信息

高分辨率对地观测系统重大专项(以下简称“高分专项”)部署建设国家真实性检验系统,目的是形成对高分共性产品进行真实性检验的能力,打造共性产品批量化生产能力,整体提高中国的高分遥感定量化应用水平。此项工作中,如何界定共性产品、共性产品之间及其与专题产品之间存在哪些生成关系是首要解决的问题。围绕这些问题,本文提出了高分专项国家真实性检验系统的总体架构,定义了高分共性产品的范畴及分级方法,探讨了共性产品体系的构建流程,以农业和交通为例,分析推导了行业专题产品生产中对共性产品的需求,进一步地,以产品树的形式推导了共性产品之间的衍生关系,明确了真实性检验系统的检验对象和应着力攻关的产品目录,对于该系统的实施具有重要的指导意义。

关键词：高分卫星共性产品专题产品产品体系产品分级真实性检验系统

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基于模拟数据分析地形校正模型效果及检验

北京师范大学学报（自然科学版） 2007年第3期43卷 255-263页

作者：闻建光柳钦火肖青中国科学院遥感应用研究所遥感科学国家重点实验室北京100101

对目前已有的多种地形校正模型(余弦校正模型、C校正模型、Minnaert模型、统计校正模型、SCS校正模型以及SCS+C校正模型)的优缺点进行了详细的评价.分析了各种地形校正模型的起源和物理意义.采用数值模拟(Li-Strahler几何光学模型(GOMS)... 详细信息

对目前已有的多种地形校正模型(余弦校正模型、C校正模型、Minnaert模型、统计校正模型、SCS校正模型以及SCS+C校正模型)的优缺点进行了详细的评价.分析了各种地形校正模型的起源和物理意义.采用数值模拟(Li-Strahler几何光学模型(GOMS))技术生成不同地形条件下的冠层反射率,并采用上述多种模型进行地形影响的消除,从理论上研究分析各种地形校正模型的特点.结果表明统计模型和C校正模型是这些地形校正模型中较好的模型方法.利用结果最优的模型方法对中国江西兴国县的地形进行校正试验,结果表明引入的C校正模型可以较优地进行地形影响的消除.

关键词：地形校正几何光学模型数值模拟