6,425 Hits in 15.8 sec

An Optimal Sampling Design for Observing and Validating Long-Term Leaf Area Index with Temporal Variations in Spatial Heterogeneities

Yelu Zeng, Jing Li, Qinhuo Liu, Yonghua Qu, Alfredo Huete, Baodong Xu, Geofei Yin, Jing Zhao
2015 Remote Sensing  
A sampling strategy to define elementary sampling units (ESUs) for an entire site at the kilometer scale is an important step in the validation process for moderate-resolution leaf area index (LAI) products  ...  for LAI measurement (LAINet) requires an optimal sampling strategy across both spatial and temporal scales.  ...  Author Contributions Jing Li and Qinhuo Liu designed the research. Yonghua Qu collected and provided the dataset of LAINet observations.  ... 
doi:10.3390/rs70201300 fatcat:6tlzqghqdre35lbtivmftddco4

Spatiotemporally Representative and Cost-Efficient Sampling Design for Validation Activities in Wanglang Experimental Site

Gaofei Yin, Ainong Li, Aleixandre Verger
2017 Remote Sensing  
Spatiotemporally representative Elementary Sampling Units (ESUs) are required for capturing the temporal variations in surface spatial heterogeneity through field measurements.  ...  and temporally fixed sampling design.  ...  Acknowledgments: This work was funded by the National Key Research and Development Program of  ... 
doi:10.3390/rs9121217 fatcat:s7za6ej5bbaljni6lb2yt3ren4

Using a Remote Sensing-Supported Hydro-Agroecological Model for Field-Scale Simulation of Heterogeneous Crop Growth and Yield: Application for Wheat in Central Europe

Tobias Hank, Heike Bach, Wolfram Mauser
2015 Remote Sensing  
Radiative transfer modeling (SLC) is used to provide maps of leaf area index from Earth Observation (EO).  ...  At the field scale, calibrated crop growth models are often applied together with empirical relations [28] or Neural Networks [29] for Leaf Area Index (LAI) retrieval.  ...  Acknowledgments The research presented in this article was conducted at the Chair of Geography and Remote Sensing, Department of Geography, Ludwig-Maximilians-Universität Munich in close cooperation with  ... 
doi:10.3390/rs70403934 fatcat:mmwigfxjtbcnrhzyf7au6cg7rm

A Multiscale Nested Sampling Method for representative albedo observations at various pixel scales

Xiaodan Wu, Jianguang Wen, Qing Xiao, Jingping Wang, Dujuan Ma, Xinwen Lin
2021 IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing  
And the sample locations were optimized with a random combination method using an index of spatiotemporal representativeness.  ...  Representative in situ observations need to be obtained to make an independent, unified, standard, and traceable validation due to the spatial scale mismatch between satellite and in situ-based observations  ...  Optimal Samplings for the 50 m Pixel The variations of Euclidean and R with NSP in different ROIs over these four areas are shown in Fig. 8 . Euclidean generally decreases with the increase of NSP.  ... 
doi:10.1109/jstars.2021.3105562 fatcat:eavlvm342nh5fmn4a6lj6bpcmq

Midday Depression vs. Midday Peak in Diurnal Light Interception: Contrasting Patterns at Crown and Leaf Scales in a Tropical Evergreen Tree

Agustina Ventre-Lespiaucq, Nicola S. Flanagan, Nhora H. Ospina-Calderón, Juan A. Delgado, Adrián Escudero
2018 Frontiers in Plant Science  
Crown architecture usually is heterogeneous as a result of foraging in spatially and temporally heterogeneous light environments.  ...  At the leaf scale, an average inclination angle of 45 • led to the midday peak in light interception, but with a huge among-leaf variation in position angles.  ...  In addition, we wanted to have an approximate idea of how spatial heterogeneity in foliage clumping affected whole-plant light interception in the long term.  ... 
doi:10.3389/fpls.2018.00727 pmid:29904391 pmcid:PMC5990892 fatcat:pvlus7hsxrba3bywoxz55c7hti

Spatial variation in Posidonia oceanica structural, morphological and dynamic features in a northwestern Mediterranean coastal area: a multi-scale analysis

E Balestri, F Cinelli, C Lardicci
2003 Marine Ecology Progress Series  
This suggests that sampling designs and analyses which incorporate different spatial scales and appropriate replications should at least be considered in the future when planning large-scale and long-term  ...  Knowledge of the natural pattern of spatial variation of the variables of interest is fundamental for designing effective sampling strategies to be used in surveys and monitoring programs.  ...  Benedetti-Cecchi for substantial help with the statistical analysis, and G. Marino, F. Vallerini and S. Bertini for sampling.  ... 
doi:10.3354/meps250051 fatcat:j4wr5y27qndmflpgk5rkzyaug4

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  
in validating various land RSPs, particularly aiming to further develop in situ sampling schemes and scaling approaches to acquire ground truth at the pixel scale over heterogeneous surfaces; (2) sound  ...  Some representative research results, with respect to the development of sampling methods and site-based validation activities, are also highlighted.  ...  Another study occurred in the midstream of the HRB, as reported in [88] , an efficient and robust LAI sampling strategy was developed based on multi-temporal prior knowledge (SMP) for long-term, fixed-position  ... 
doi:10.3390/rs8120980 fatcat:yuvycxfe2vcidj6zj2omvnaqqu

Using VEGNET In-Situ Monitoring LiDAR (IML) to Capture Dynamics of Plant Area Index, Structure and Phenology in Aspen Parkland Forests in Alberta, Canada

Carlos Portillo-Quintero, Arturo Sanchez-Azofeifa, Darius Culvenor
2014 Forests  
Our results indicate that the VEGNET IML has great potential for rapid forest structural characterization and for ground validation of PAI/LAI at a temporal frequency compatible with earth observation  ...  As an alternative to these methods, we used an In-Situ Monitoring LiDAR system that provides indirect measures of PAI and Plant Area Volume Density (PAVD) at a fixed angle, based on optimized principles  ...  Acknowledgments This work was supported in part by a TecTerra grant 1209-UNI-013. Access to the study site was provided by the Alberta Environment and Sustainable Resource Development (ESRD).  ... 
doi:10.3390/f5051053 fatcat:ondudabnnjglnpjd2d6w4kkoy4

A review of in-situsampling protocols to support the remote sensing of vegetation

Vicente Burchard-Levine, David Riaño Arribas, Lara Vilar del Hoyo
2022 Geofocus  
A review of in-situ sampling protocols to support the remote sensing of vegetation, GeoFocus,  ...  Acknowledgements The research received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie TRuStEE project (grant agreement No 721995).  ...  for understory species in heterogeneous sampling areas.  ... 
doi:10.21138/gf.780 fatcat:2majeqgvzfcqheavpvygtglc54

Estimating the Maximal Light Use Efficiency for Different Vegetation through the CASA Model Combined with Time-Series Remote Sensing Data and Ground Measurements

Ainong Li, Jinhu Bian, Guangbin Lei, Chengquan Huang
2012 Remote Sensing  
and ecosystem productivity by combining the LUE-based model with remote sensing observations.  ...  Based on an existing land cover map and MODIS NDVI product, the linear unmixing method with a moving window was adopted to estimate the time-series NDVI for different end members in a MODIS NDVI pixel;  ...  Acknowledgements We are grateful to the anonymous referees for their valuable comments and suggestions. We also wish to express our gratitude to all the contractors and image providers.  ... 
doi:10.3390/rs4123857 fatcat:z3u5nukzwzfgdpty5fiqioccry

High-resolution modeling of the spatial heterogeneity of soil moisture: Applications in network design

Nathaniel W. Chaney, Joshua K. Roundy, Julio E. Herrera-Estrada, Eric F. Wood
2015 Water Resources Research  
The spatial heterogeneity of soil moisture remains a persistent challenge in the design of in situ measurement networks, spatial downscaling of coarse estimates (e.g., satellite retrievals), and hydrologic  ...  We calibrate and validate the TOPLATS distributed hydrologic model with high to moderate resolution land and meteorological data sets to provide daily soil moisture fields between 2004 and 2008.  ...  land evaporative processes and land-atmosphere interactions in the NCEP Global Forecast System (GFS) and Climate Forecast System (CFS), and NSF grant 1144217 (Petascale Design and Management of Satellite  ... 
doi:10.1002/2013wr014964 fatcat:hneebqeznjdvvlcee7mbb464la

Detection of the Coupling between Vegetation Leaf Area and Climate in a Multifunctional Watershed, Northwestern China

Lu Hao, Cen Pan, Peilong Liu, Decheng Zhou, Liangxia Zhang, Zhe Xiong, Yongqiang Liu, Ge Sun
2016 Remote Sensing  
with the variability of an aridity index (AI = Precipitation/Potential Evapotranspiration).  ...  We apply empirical orthogonal function (EOF) and singular value decomposition (SVD) analysis to isolate and identify the spatial patterns of satellite-derived leaf area index (LAI) and their close relationship  ...  The research method using long term satellite-derived leaf area index (LAI) datasets and downscaling regional climate gridded data series is well equipped to study long term patterns.  ... 
doi:10.3390/rs8121032 fatcat:yjntxim25jeh5aorehzjizt7d4

Scaling net primary production to a MODIS footprint in support of Earth observing system product validation

D. P. Turner, S. Ollinger, M.-l. Smith, O. Krankina, M. Gregory
2004 International Journal of Remote Sensing  
Generally, the optimal procedure for scaling NPP to a MODIS footprint will depend on local vegetation type, the scale of spatial heterogeneity, and available resources.  ...  Release of an annual global terrestrial net primary production (NPP) data layer has begun in association with the Moderate Imaging Spectroradiometer (MODIS) sensor, a component of the NASA Earth Observing  ...  We are grateful to (1) Julian Jenkins and Rita Freuder for their assistance with the case study 3 involving PnET NPP modelling, and (2) Tom Gower for making the field measurements for case study 1.  ... 
doi:10.1080/0143116031000150013 fatcat:x2hhctcobrdbnh5melgobc46hy

Simulation of Forest Carbon Fluxes Using Model Incorporation and Data Assimilation

Min Yan, Xin Tian, Zengyuan Li, Erxue Chen, Xufeng Wang, Zongtao Han, Hong Sun
2016 Remote Sensing  
Firstly, current model calibration or parameter optimization neglected the requirement of spatial and temporal variation in the ecophysiological parameters of the process-based model.  ...  The technique used in this study offers a strategy of simulating forest carbon fluxes with temporal and spatial continuity and making full use of time series remote sensing data, the optimized MOD_17 model  ...  The eddy covariance measurements in this study were obtained from ChinaFlux. We would also like to thank Beijing Normal University for providing the GLASS products.  ... 
doi:10.3390/rs8070567 fatcat:ijdbhufdhjaw5janj6q64kibum

Drone data reveal heterogeneity in tundra greenness and phenology not captured by satellites

Jakob J Assmann, Isla H Myers-Smith, Jeffrey T Kerby, Andrew M Cunliffe, Gergana N Daskalova
2020 Environmental Research Letters  
We identified a plateau in the spatial variation of tundra greenness at distances of around half a metre in the plots, suggesting that these grain sizes are optimal for monitoring such variation in the  ...  We combined time-series of the Normalised Difference Vegetation Index (NDVI) from multispectral drone imagery and satellite data (Sentinel-2, Landsat 8 and MODIS) with ground-based observations for two  ...  Acknowledgments We would like to thank the Team Shrub field crews of the 2016 and 2017 field seasons for their hard work and effort invested in collecting the data presented in this research, this includes  ... 
doi:10.1088/1748-9326/abbf7d fatcat:zfjavzagtvgnjcyzjp4mant6pq
« Previous Showing results 1 — 15 out of 6,425 results