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A Simulation-based Analysis of Topographic Effects on LAI Inversion Over Sloped Terrain

Wentao Yu, Jing Li, Qinhuo Liu, Gaofei Yin, Yelu Zeng, Shangrong Lin, Jing Zhao
2020 IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing  
In this article, the topographic effects on LAI inversion over sloped terrain are quantitatively investigated and analyzed based on a dataset generated from the discrete anisotropy radiative transfer model  ...  The results are helpful in understanding the topographic effects and further finding a better strategy for LAI inversion over sloped terrain.  ...  DISCUSSION This article explored the effects of topography on LAI inversion over sloped terrain. The analysis was performed based on DART simulations.  ... 
doi:10.1109/jstars.2020.2970999 fatcat:nvrwujfhqnce3awazpnmxn6zlm

Sensitivity of Coarse‐Scale Snow‐Free Land Surface Shortwave Albedo to Topography

Dalei Hao, Jianguang Wen, Qing Xiao, Xingwen Lin, Dongqin You, Yong Tang, Qiang Liu, Sisi Zhang
2019 Journal of Geophysical Research - Atmospheres  
and the variance-based global sensitivity analysis based on a well-established mechanistically-based land surface albedo parameterized model over rugged terrain.  ...  In spite of gradually increasing research about the topographic effects on the albedo, the albedo sensitivities over rugged terrain to different variables remain unclear.  ...  We thank Jochem Verrelst and Juan Pablo Rivera for providing the guidance and assistance for the use of the GSA module in the Automated Radiative Transfer Models Operator (ARTMO) software, which can be  ... 
doi:10.1029/2019jd030660 fatcat:qoy343xghfcc7dovi4knexlubm

Study of the Remote Sensing Model of FAPAR over Rugged Terrains

Peng Zhao, Wenjie Fan, Yuan Liu, Xihan Mu, Xiru Xu, Jingjing Peng
2016 Remote Sensing  
The FAPAR-P model was also developed to calculate the FAPAR based on recollision probability [19] . In all these FAPAR models, the effect of rugged terrain on FAPAR calculation was not included.  ...  MODIS LAI and FAPAR products are derived from a global scale process model.  ...  Special thanks are extended to Hongmin Zhou of the Beijing Normal University for assisting in the measurement of the PAR over the canopy in Weichang.  ... 
doi:10.3390/rs8040309 fatcat:zej7hvyexfbyzgrmuzyx4slxt4

Improved topographic correction of forest image data using a 3‐D canopy reflectance model in multiple forward mode

S. A. Soenen, D. R. Peddle, C. A. Coburn, R. J. Hall, F. G. Hall
2008 International Journal of Remote Sensing  
To address these problems, we present MFM-TOPO as a new physically-based modelling (PBM) approach for normalising topographically induced signal variance as a function of forest stand structure and sub-pixel  ...  For example, pine class accuracy was increased by 62% over shaded slopes, and spruce class accuracy was increased by 13% over more moderate slopes.  ...  any specified slope and aspect, such as simulating a 20u slope from a 45u slope, or, conversely, forest stand pixels on flat terrain could be simulated in terms of their corresponding reflectance on steeper  ... 
doi:10.1080/01431160701311291 fatcat:vdqqwbunofaxhk7omohx6hrsn4

Characterizing Land Surface Anisotropic Reflectance over Rugged Terrain: A Review of Concepts and Recent Developments

Jianguang Wen, Qiang Liu, Qing Xiao, Qinhuo Liu, Dongqin You, Dalei Hao, Shengbiao Wu, Xingwen Lin
2018 Remote Sensing  
In this paper, after a brief introduction of the theoretical background of the BRDF over rugged terrain, the status of estimating land surface BRDF properties over rugged terrain is comprehensively reviewed  ...  The discussion focuses on land surface reflectance retrieval over mountainous areas, the difference in solo slope and composite slope BRDF models, and suggested future research to improve the accuracy  ...  Conflicts of Interest: The authors declare no conflict of interest.  ... 
doi:10.3390/rs10030370 fatcat:ayydrp5kunflfdfka3atsvqwge

Spatial Downscaling of Gross Primary Productivity Using Topographic and Vegetation Heterogeneity Information: A Case Study in the Gongga Mountain Region of China

Xinyao Xie, Ainong Li, Huaan Jin, Gaofei Yin, Jinhu Bian
2018 Remote Sensing  
In this study, a downscaling algorithm was developed to model gross primary productivity (GPP) at 500 m in a time series over rugged terrain, which considered the effects of spatial heterogeneity on carbon  ...  The proposed downscaling algorithm could provide a reference when considering the effects of spatial heterogeneity on carbon flux simulations and retrieving other fine resolution ecological-physiology  ...  The purpose of the downscaling method based on topographic factors and the LAI is to predict GPP r (x) at a 500 m resolution.  ... 
doi:10.3390/rs10040647 fatcat:h7ho4c6b4ncizf4y2nssbvh6bq

Terrain Sensitivity in Environmental Models

Vít Voženílek
2002 Geografie-Sbornik CGS  
A terrain (Earth's surface) is often included as crucial factor of modelled processes. Terrain is a continuous phenomenon that is represented by various discrete or networked means.  ...  This dimensional variability in representation process impacts in both inherent terrain parameters (incl. surface forms) and modelled outcomes.  ...  In general, a sensitivity analysis establishes the effect of the different available techniques on any model outputs.  ... 
doi:10.37040/geografie2002107020111 fatcat:i5xvy7i2nvdupbgzuoo2ugesya

Estimating Forest fAPAR from Multispectral Landsat-8 Data Using the Invertible Forest Reflectance Model INFORM

Huili Yuan, Ronghua Ma, Clement Atzberger, Fei Li, Steven Loiselle, Juhua Luo
2015 Remote Sensing  
transfer model (Invertible Forest Reflectance Model, INFORM) combined with an inversion strategy based on artificial neural nets (ANN).  ...  The estimation of the Fraction of Absorbed Photosynthetically Active Radiation in forests (forest fAPAR) from multi-spectral Landsat-8 data is investigated in this paper using a physically based radiative  ...  Academy of Sciences.  ... 
doi:10.3390/rs70607425 fatcat:jedbh7sldjbdtn66u33ppysrpq

A Multi-Scale Validation Strategy for Albedo Products over Rugged Terrain and Preliminary Application in Heihe River Basin, China

Xingwen Lin, Jianguang Wen, Qinhuo Liu, Qing Xiao, Dongqin You, Shengbiao Wu, Dalei Hao, Xiaodan Wu
2018 Remote Sensing  
Results showed that the MRT-based model was effective and suitable for conducting the validation of MODIS albedo products over rugged terrain.  ...  The uncertainty distribution analysis showed that the largest scaling uncertainty was at the pixels over rugged terrain and its uncertainty of MODIS was as high as 0.07, when neglecting the scale effects  ...  The simulated results showed that the SZA and mean slope had a significant influence on the scale effects of albedo over rugged terrain.  ... 
doi:10.3390/rs10020156 fatcat:g37463plxbbhflxdf25lrsmnma

Modeling Top of Atmosphere Radiance over Heterogeneous Non-Lambertian Rugged Terrain

Alijafar Mousivand, Wout Verhoef, Massimo Menenti, Ben Gorte
2015 Remote Sensing  
A detailed account for BRDF effects, adjacency effects and topography effects on the radiance modeling is given, in which sky-view factor and non-Lambertian reflected radiance from adjacent slopes are  ...  In this paper, a system for top of atmosphere radiance modeling over heterogeneous non-Lambertian rugged terrain through radiative transfer modeling is presented.  ...  All authors contributed to the scientific content, the interpretation of the results and manuscript revisions. Conflicts of Interest The authors declare no conflict of interest.  ... 
doi:10.3390/rs70608019 fatcat:nkw6r3w42vhkdpgeu5rnpvsrd4

Impact of Hillslope-Scale Organization of Topography, Soil Moisture, Soil Temperature, and Vegetation on Modeling Surface Microwave Radiation Emission

A.N. Flores, V.Y. Ivanov, D. Entekhabi, R.L. Bras
2009 IEEE Transactions on Geoscience and Remote Sensing  
Local incidence and polarization rotation angles are explicitly computed, with knowledge of the local terrain slope and aspect as well as the sky position of the sensor.  ...  Including hillslope-scale heterogeneity in factors effecting emission can change watershed-aggregated brightness temperature by more than 2 K, depending on topographic ruggedness.  ...  A. N. Flores would like to thank R. Koster for graciously providing important comments to an earlier version of the manuscript.  ... 
doi:10.1109/tgrs.2009.2014743 fatcat:t64gz3acpneppirm5g5ed34v5u

Ecosystem processes at the watershed scale: Mapping and modeling ecohydrological controls of landslides

Lawrence E. Band, T. Hwang, T.C. Hales, James Vose, Chelcy Ford
2012 Geomorphology  
As the model has previously been shown to simulate space/time patterns of coupled water, carbon and nutrient cycling, the integration of slope stability as a function of hydrologic, ecosystem and geomorphic  ...  Mountain watersheds are sources of a set of valuable ecosystem services as well as potential hazards.  ...  We thank Dean Urban of Duke University for use of his soil depth data set and Rick Wooten of the North Carolina Geological Survey for discussion and sharing data on soil mechanical properties.  ... 
doi:10.1016/j.geomorph.2011.06.025 fatcat:lzxocnvrlrck5lmdr4dzboodku

Assessment of the impacts of surface topography, off-nadir pointing and vegetation structure on vegetation lidar waveforms using an extended geometric optical and radiative transfer model

Wenze Yang, Wenge Ni-Meister, Shihyan Lee
2011 Remote Sensing of Environment  
For an off-nadir pointing laser penetrating vegetation over a slope terrain, the waveform is either stretched or compressed based on the relative angle.  ...  based only on the shapes of waveform without knowing any surface topography information.  ...  The authors would like to thank Ralph Dubayah, Forrest Hall, Guoqing Sun and Jon Ranson for valuable discussion on the paper.  ... 
doi:10.1016/j.rse.2010.02.021 fatcat:uipodpz4fzcezegyia5meirhui

Forest above Ground Biomass Inversion by Fusing GLAS with Optical Remote Sensing Data

Xiaohuan Xi, Tingting Han, Cheng Wang, Shezhou Luo, Shaobo Xia, Feifei Pan
2016 ISPRS International Journal of Geo-Information  
The ASTER DEM was used to compute the terrain index for reducing the topographic influence on the GLAS canopy height estimation.  ...  A series of biomass estimation models were developed and validated using regression analyses between field-estimated biomass, canopy height, and LAI.  ...  Conflicts of Interest: The authors declare no conflict of interest.  ... 
doi:10.3390/ijgi5040045 fatcat:t6vcttqak5egnad2n2tpt2xqtq

The effects of spatial aggregation of complex topography on hydroecological process simulations within a rugged forest landscape: development and application of a satellite-based topoclimatic model

S Kang, D Lee, J S Kimball
2004 Canadian Journal of Forest Research  
We evaluated the effects of topographic complexity on landscape carbon and hydrologic process simulations within a rugged mixed hardwood forest by developing and applying a satellite-based hydroecological  ...  Our modeling analysis showed that the effect of topography was the strongest on solar radiation and temperature, intermediate on soil water and evapotranspiration, and ambiguous on soil respiration.  ...  This research was supported by a Korean Science and Engineering Foundation grant KOSEF 2000-2-51300-002-3 and by the Eco-technopia 21 Project, Ministry of Environment, Republic of Korea.  ... 
doi:10.1139/x03-213 fatcat:awiq2wpcejgetd6km36tb6de5i
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