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Validation of Regional-Scale Remote Sensing Products in China: From Site to Network

Shuguo Wang, Xin Li, Yong Ge, Rui Jin, Mingguo Ma, Qinhuo Liu, Jianguang Wen, Shaomin Liu
2016 Remote Sensing  
Validation is mandatory to quantify the reliability of remote sensing products (RSPs).  ...  The development of this VS improves our understanding of validation issues, especially to facilitate validating RSPs over heterogeneous land surfaces both at the pixel scale level and the product level  ...  Acknowledgments: This research was supported by the Natural Science Foundation of China projects  ... 
doi:10.3390/rs8120980 fatcat:yuvycxfe2vcidj6zj2omvnaqqu

An integrated method for validating long-term leaf area index products using global networks of site-based measurements

Baodong Xu, Jing Li, Taejin Park, Qinhuo Liu, Yelu Zeng, Gaofei Yin, Jing Zhao, Weiliang Fan, Le Yang, Yuri Knyazikhin, Ranga B. Myneni
2018 Remote Sensing of Environment  
A B S T R A C T Long-term ground LAI measurements from the global networks of sites (e.g. FLUXNET) have emerged as a promising data source to validate remotely sensed global LAI product time-series.  ...  Here, we propose an approach (Grading and Upscaling of Ground Measurements, GUGM) that integrates a spatial representativeness grading criterion and a spatial upscaling strategy to resolve this scale-mismatch  ...  We also are grateful for the Landsat Surface Reflectance products courtesy of the U.S.  ... 
doi:10.1016/j.rse.2018.02.049 fatcat:ocluwquft5bgdcoez7xq7cblxm

Wireless Sensor Network of Typical Land Surface Parameters and Its Preliminary Applications for Coarse-Resolution Remote Sensing Pixel

Baocheng Dou, Jianguang Wen, Xiuhong Li, Qiang Liu, Jingjing Peng, Qing Xiao, Zhigang Zhang, Yong Tang, Xiaodan Wu, Xingwen Lin, Dongqin You, Hua Li (+4 others)
2016 International Journal of Distributed Sensor Networks  
The preliminary applications, which validate several remote sensing products with CPP-WSN data, demonstrate that a high quality ground "truth" dataset has been available for remote sensing as well as other  ...  How to obtain the "truth" of land surface parameter as reference value to validate the remote sensing retrieved parameter in heterogeneous scene and coarse-resolution pixel is one of the most challenging  ...  The sinusoidal grid is one of the most widely used grid schemes for global remote sensing products.  ... 
doi:10.1155/2016/9639021 fatcat:jcn7zwavvnghvemlnaibhhueza

Upscaling Evapotranspiration from a Single-Site to Satellite Pixel Scale

Xiang Li, Shaomin Liu, Xiaofan Yang, Yanfei Ma, Xinlei He, Ziwei Xu, Tongren Xu, Lisheng Song, Yuan Zhang, Xiao Hu, Qian Ju, Xiaodong Zhang
2021 Remote Sensing  
It is of great significance for the validation of remotely sensed evapotranspiration (ET) products to solve the spatial-scale mismatch between site observations and remote sensing estimations.  ...  the globe for remotely sensed ET products' validation.  ...  In addition to accuracy validation of the ET at the satellite pixel scale, it is also important to quantify the uncertainty of the upscaled ET for the validation of remotely sensed ET products.  ... 
doi:10.3390/rs13204072 fatcat:uedxv2clzbc67hnbhkohv5jfli

Upscaling leaf area index in an Arctic landscape through multiscale observations

M. WILLIAMS, R. BELL, L. SPADAVECCHIA, L. E. STREET, M. T. VAN WIJK
2008 Global Change Biology  
I also implemented the geostatistical analysis used for the extrapolation sections of the paper. I provided the text for the sections entitled remote sensing (3.4.3) and geospatial methods (3.4.4).  ...  I analysed the relationship between the EO (Landsat) dervided LAI and the ground observations, and calculated the semivariograms.  ...  We thank Sven Rasmussen for field assistance, and Terry Callaghan for the support and facilities of the Abisko Research Station, and Paul Stoy for his comments on the manuscript.  ... 
doi:10.1111/j.1365-2486.2008.01590.x fatcat:cqywxofzojd7bk7mcvzxwi426i

Using Information Theory to Determine Optimum Pixel Size and Shape for Ecological Studies: Aggregating Land Surface Characteristics in Arctic Ecosystems

P. C. Stoy, M. Williams, L. Spadavecchia, R. A. Bell, A. Prieto-Blanco, J. G. Evans, M. T. van Wijk
2009 Ecosystems  
We investigated the 'optimum' pixel size and shape for averaging leaf area index (LAI) measurements in relatively large (85 m 2 estimates on a 600 9 600-m 2 grid) and small (0.04 m 2 measurements on a  ...  Land surface heterogeneity is commonly characterized using rectangular pixels, whose length scale reflects that of remote sensing measurements or ecological models rather than the spatial scales at which  ...  We would like to thank Willem Bouten for use of the LAI-2000, Lorna Street and Sven Rasmussen for field assistance, Ben Poulter for ArcGIS assistance, Terry Callaghan and  ... 
doi:10.1007/s10021-009-9243-7 fatcat:mfsemqodrbayze42hstwkfyrum

Integrated Validation of Coarse Remotely Sensed Evapotranspiration Products over Heterogeneous Land Surfaces

Yuan Zhang, Shaomin Liu, Lisheng Song, Xiang Li, Zhenzhen Jia, Tongren Xu, Ziwei Xu, Yanfei Ma, Ji Zhou, Xiaofan Yang, Xinlei He, Yunjun Yao (+1 others)
2022 Remote Sensing  
This framework was applied at the pixel and river basin scales, using direct and indirect validation methods with multisource validation datasets, which solved the spatial mismatch between ground measurements  ...  and remotely sensed products.  ...  The divergence for the remotely sensed ET validation results using the ground tr vs. ground observation ET from homogeneous to heterogeneous surfaces at the spatial res of 1 km.  ... 
doi:10.3390/rs14143467 fatcat:sfimhsy7anaozlcxbs7tbpzeqq

Spatial representativeness and uncertainty of eddy covariance carbon flux measurements for upscaling net ecosystem productivity to the grid scale

Youhua Ran, Xin Li, Rui Sun, Natascha Kljun, Lei Zhang, Xufeng Wang, Gaofeng Zhu
2016 Agricultural and Forest Meteorology  
Based on the HiWATER-MUSOEXE data, this study evaluated the spatial representativeness and uncertainty of EC CO 2 flux measurements for upscaling to the grid scale using a scheme that combines a footprint  ...  However, EC measurements represent an integrated flux over their footprint area, which usually differs from respective model grids or remote sensing pixels.  ...  We thank the editor and two anonymous reviewers for their extremely helpful comments on this paper.  ... 
doi:10.1016/j.agrformet.2016.05.008 fatcat:pbexcoy6hres5bpsca767nzqza

Observing Ecohydrological Processes: Challenges and Perspectives [chapter]

Xin Li, Harry Vereecken, Chunfeng Ma
2019 Observation and Measurement of Ecohydrological Processes  
By using proper scaling methods, in situ measurements can be scaled to pixel-scale truth data and used to validate remote sensing products (Kang et al. 2015; ).  ...  The HiWATER observing system is composed of a flux matrix, a wireless sensor network for measuring soil moisture and the LAI, isotope observations, and airborne remote sensing.  ... 
doi:10.1007/978-3-662-48297-1_1 fatcat:irydzknmerhphnzhroefn7nlcq

An Intercomparison Study of Algorithms for Downscaling SMAP Radiometer Soil Moisture Retrievals

Li Fang, Xiwu Zhan, Jifu Yin, Jicheng Liu, Mitchell Schull, Jeffrey P. Walker, Jun Wen, Michael H. Cosh, Tarendra Lakhankar, Chandra Holifield Collins, David D. Bosch, Patrick J. Starks
2020 Journal of Hydrometeorology  
Soil moisture measurements of the in situ networks were upscaled to the corresponding SMAP reference pixels at 9 km and used to assess the accuracy of downscaled products at a 9-km scale.  ...  In general, this method is promising for operational generation of fine-resolution soil moisture data product.  ...  The manuscript contents are solely the opinions of the authors and do not constitute a statement of policy, decision, or position on behalf of NOAA or the U. S. Government.  ... 
doi:10.1175/jhm-d-19-0034.1 fatcat:dasatlfgmjglvcf5w5xqkolxli

Quantifying Uncertainty and Bridging the Scaling Gap in the Retrieval of Leaf Area Index by Coupling Sentinel-2 and UAV Observations

Andrew Revill, Anna Florence, Alasdair MacArthur, Stephen Hoad, Robert Rees, Mathew Williams
2020 Remote Sensing  
We used Gaussian processes regression machine learning to calibrate a UAV model for LAI, based on ground data.  ...  We anticipate that our UAV calibration approach to resolving spatial heterogeneity would enhance the retrieval accuracy of LAI and additional biophysical variables for other arable crop types and a broader  ...  Acknowledgments: We would like to thank the farmers on Farms 1 and 2 for consenting to the field survey campaigns carried out across their properties.  ... 
doi:10.3390/rs12111843 fatcat:ifdtru2noveknagnga7m6kxucm

Upscaling ground observations of vegetation water content, canopy height, and leaf area index during SMEX02 using aircraft and Landsat imagery

M ANDERSON, C NEALE, F LI, J NORMAN, W KUSTAS, H JAYANTHI, J CHAVEZ
2004 Remote Sensing of Environment  
Microwave-based remote sensing algorithms for mapping soil moisture are sensitive to water contained in surface vegetation at moderate levels of canopy cover.  ...  This study compares the relative utility of high-resolution (1.5 m) aircraft and coarserresolution (30 m) Landsat imagery in upscaling an extensive set of ground-based measurements of canopy biophysical  ...  Logistical support from the USDA-ARS National Soil Tilth Lab was critical to the success of both field campaigns.  ... 
doi:10.1016/j.rse.2004.03.019 fatcat:fifddchuszac7bujfxmctcruti

A Critical Comparison of Remote Sensing Leaf Area Index Estimates over Rice-Cultivated Areas: From Sentinel-2 and Landsat-7/8 to MODIS, GEOV1 and EUMETSAT Polar System

Manuel Campos-Taberner, Francisco García-Haro, Lorenzo Busetto, Luigi Ranghetti, Beatriz Martínez, María Amparo Gilabert, Gustau Camps-Valls, Fernando Camacho, Mirco Boschetti
2018 Remote Sensing  
This is the first study that provides a quantitative assessment on the quality of available operational LAI product for rice monitoring to both the scientific community and users of agro-monitoring operational  ...  The comparison was performed to assess overall quality of LAI estimates for rice, as a fundamental input of different scale (regional to local) operational crop monitoring systems such as the ones developed  ...  Acknowledgments: The research leading to these results was conducted within the ERMES FP7 project (http: //www.ermes-fp7space.eu/) which received funding from the European Union Seventh Framework Program  ... 
doi:10.3390/rs10050763 fatcat:eomdnkfypvcdjpam6wezwecgey

Characterizing the Error and Bias of Remotely Sensed LAI Products: An Example for Tropical and Subtropical Evergreen Forests in South China

Yuan Zhao, Xiaoqiu Chen, Thomas Luke Smallman, Sophie Flack-Prain, David T. Milodowski, Mathew Williams
2020 Remote Sensing  
Here, we used nearly 8000 in situ measurements of LAI from six forest environments in southern China to evaluate the magnitude, uncertainty, and dynamics of three widely used EO LAI products.  ...  The uncertainties estimated by each of the EO products are substantially smaller (3–5 times) than the observed bias for EO products against in situ measurements.  ...  Conflicts of Interest: The authors declare no conflict of interest.  ... 
doi:10.3390/rs12193122 doaj:bef1e1532ef7441aa9d6118115ffb675 fatcat:ohwdtsriczhibf7loxo5lhzbqu

Toward Global Soil Moisture Monitoring With Sentinel-1: Harnessing Assets and Overcoming Obstacles

2018 IEEE Transactions on Geoscience and Remote Sensing  
It includes the novel Dynamic Gaussian Upscaling (DGU) method for spatial upscaling of SAR imagery, harnessing its field-scale information and successfully mitigating effects from the SAR's high signal  ...  Also, a new regression-based approach for estimating the radar slope is defined, coping with Sentinel-1's inhomogeneity in spatial coverage.  ...  We also thank the Italian Civil Protection Department for providing the rainfall maps.  ... 
doi:10.1109/tgrs.2018.2858004 fatcat:zgh7pbc64nft7kowbcnzaekdrq
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