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Articles 61 - 90 of 130

Full-Text Articles in Remote Sensing

Landsat 15-M Panchromatic-Assisted Downscaling (Lpad) Of The 30-M Reflective Wavelength Bands To Sentinel-2 20-M Resolution, Zhongbin Li, Hankui K. Zhang, David P. Roy, Lin Yan, Haiyan Huang, Jian Li Jul 2017

Landsat 15-M Panchromatic-Assisted Downscaling (Lpad) Of The 30-M Reflective Wavelength Bands To Sentinel-2 20-M Resolution, Zhongbin Li, Hankui K. Zhang, David P. Roy, Lin Yan, Haiyan Huang, Jian Li

GSCE Faculty Publications

The Landsat 15-m Panchromatic-Assisted Downscaling (LPAD) method to downscale Landsat-8 Operational Land Imager (OLI) 30-m data to Sentinel-2 multi-spectral instrument (MSI) 20-m resolution is presented. The method first downscales the Landsat-8 30-m OLI bands to 15-m using the spatial detail provided by the Landsat-8 15-m panchromatic band and then reprojects and resamples the downscaled 15-m data into registration with Sentinel-2A 20-m data. The LPAD method is demonstrated using pairs of contemporaneous Landsat-8 OLI and Sentinel-2A MSI images sensed less than 19 min apart over diverse geographic environments. The LPAD method is shown to introduce less spectral and spatial distortion and …

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Application Of Iterative Noise-Adding Procedures For Evaluation Of Moment Distance Index For Lidar Waveforms, Eric Ariel L. Salas, Sadichya Amatya, Geoffrey Henebry Jun 2017

Application Of Iterative Noise-Adding Procedures For Evaluation Of Moment Distance Index For Lidar Waveforms, Eric Ariel L. Salas, Sadichya Amatya, Geoffrey Henebry

GSCE Faculty Publications

The new Moment Distance (MD) framework uses the backscattering profile captured in waveform LiDAR data to characterize the complicated waveform shape and highlight specific regions within the waveform extent. To assess the strength of the new metric for LiDAR application, we use the full-waveform LVIS data acquired over La Selva, Costa Rica in 1998 and 2005. We illustrate how the Moment Distance Index (MDI) responds to waveform shape changes due to variations in signal noise levels. Our results show that the MDI is robust in the face of three different types of noise—additive, uniform additive, and impulse. In effect, the …

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Comparisons Of Global Land Surface Seasonality And Phenology Derived From Avhrr, Modis And Viirs Data, Xiaoyang Zhang May 2017

Comparisons Of Global Land Surface Seasonality And Phenology Derived From Avhrr, Modis And Viirs Data, Xiaoyang Zhang

Global Land Surface Season Data Sets

The data set in this collection is for the paper Comparisons of Global Land Surface Seasonality and Phenology Derived from AVHRR, MODIS and VIIRS Data which will be published in the "Journal of Geophysical Research: Biogeosciences."

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Impacts Of Thermal Time On Land Surface Phenology In Urban Areas, Cole Krehbiel, Xiaoyang Zhang, Geoffrey Henebry May 2017

Impacts Of Thermal Time On Land Surface Phenology In Urban Areas, Cole Krehbiel, Xiaoyang Zhang, Geoffrey Henebry

GSCE Faculty Publications

Urban areas alter local atmospheric conditions by modifying surface albedo and consequently the surface radiation and energy balances, releasing waste heat from anthropogenic uses, and increasing atmospheric aerosols, all of which combine to increase temperatures in cities, especially overnight, compared with surrounding rural areas, resulting in a phenomenon called the “urban heat island" effect. Recent rapid urbanization of the planet has generated calls for remote sensing research related to the impacts of urban areas and urbanization on the natural environment. Spatially extensive, high spatial resolution data products are needed to capture phenological patterns in regions with heterogeneous land cover and …

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Examination Of The Potential Of Terrestrial Laser Scanning And Structure-From-Motion Photogrammetry For Rapid Nondestructive Field Measurement Of Grass Biomass, Sam D. Cooper, David P. Roy, Crystal B. Schaaf, Ian Paynter May 2017

Examination Of The Potential Of Terrestrial Laser Scanning And Structure-From-Motion Photogrammetry For Rapid Nondestructive Field Measurement Of Grass Biomass, Sam D. Cooper, David P. Roy, Crystal B. Schaaf, Ian Paynter

GSCE Faculty Publications

Above ground biomass (AGB) is a parameter commonly used for assessment of grassland systems. Destructive AGB measurements, although accurate, are time consuming and are not easily undertaken on a repeat basis or over large areas. Structure-from-Motion (SfM) photogrammetry and Terrestrial Laser Scanning (TLS) are two technologies that have the potential to yield precise 3D structural measurements of vegetation quite rapidly. Recent advances have led to the successful application of TLS and SfM in woody biomass estimation, but application in natural grassland systems remains largely untested. The potential of these techniques for AGB estimation is examined considering 11 grass plots with …

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Grand Challenges In Understanding The Interplay Of Climate And Land Changes, Shuguang Liu, Ben Bond-Lamberty, Lena R. Boysen, James D. Ford, Andrew Fox, Kevin Gallo, Jerry Hatfield, Geoffrey M. Henebry, Thomas G. Huntington, Zhihua Liu, Thomas R. Loveland, Richard J. Norby, Terry Sohl, Allison L. Steiner, Wenping Yuan, Zhao Zhang, Shuqing Zhao Apr 2017

Grand Challenges In Understanding The Interplay Of Climate And Land Changes, Shuguang Liu, Ben Bond-Lamberty, Lena R. Boysen, James D. Ford, Andrew Fox, Kevin Gallo, Jerry Hatfield, Geoffrey M. Henebry, Thomas G. Huntington, Zhihua Liu, Thomas R. Loveland, Richard J. Norby, Terry Sohl, Allison L. Steiner, Wenping Yuan, Zhao Zhang, Shuqing Zhao

GSCE Faculty Publications

Half of Earth’s land surface has been altered by human activities, creating various consequences on the climate and weather systems at local to global scales, which in turn affect a myriad of land surface processes and the adaptation behaviors. This study reviews the status and major knowledge gaps in the interactions of land and atmospheric changes and present 11 grand challenge areas for the scientific research and adaptation community in the coming decade. These land-cover and land-use change (LCLUC)-related areas include 1) impacts on weather and climate, 2) carbon and other biogeochemical cycles, 3) biospheric emissions, 4) the water cycle, …

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Forest Inventory Data, Izaya Numata, Mark Cochrane, Jeppe Kjaersgaard, Sonaira Souza Da Silva Apr 2017

Forest Inventory Data, Izaya Numata, Mark Cochrane, Jeppe Kjaersgaard, Sonaira Souza Da Silva

Drought in Amazonia Data Sets

Forest inventory was conducted in Acre, the southwestern Amazon, in July-August in 2014. Field data was collected in four fragmented forest areas. In addition, this forest inventory includes data in forest areas burned in 2005 and 2010 and unburned forest areas. Forest inventory includes information on vegetation species and stem diameter at breast height (DBH) at each plot of 25m x 25m. All trees with DBH ≥ 10cm were measured at 25m x 25m plots and those with DBH< 10cm and lianas were measured at 10m x 10m and 5m x 5m subplots within each 25m x 25m plot.

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Exploration Of Scaling Effects On Coarse Resolution Land Surface Phenology, Xiaoyang Zhang, Jianmin Wang, Feng Gao, Yan Liu, Crystal Schaaf, Mark Friedl, Yunyue Yu, Senthilnath Jayavelu, Joshua Gray, Lingling Liu, Dong Yan, Geoffrey M. Henebry Mar 2017

Exploration Of Scaling Effects On Coarse Resolution Land Surface Phenology, Xiaoyang Zhang, Jianmin Wang, Feng Gao, Yan Liu, Crystal Schaaf, Mark Friedl, Yunyue Yu, Senthilnath Jayavelu, Joshua Gray, Lingling Liu, Dong Yan, Geoffrey M. Henebry

GSCE Faculty Publications

Numerous land surface phenology (LSP) datasets have been produced from various coarse resolution satellite data and different detection algorithms from regional to global scales. In contrast to field-observed phenological events that are defined by clearly evident organismal changes with biophysical meaning, current approaches to detecting transitions in LSP only determine the timing of variations in remotely sensed observations of surface greenness. Since activities to bridge LSP and field observations are challenging and limited, our understanding of the biophysical characteristics of LSP transitions is poor. Therefore, we set out to explore the scaling effects on LSP transitions at the nominal start …

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Integrating Malaria Surveillance With Climate Data For Outbreak Detection And Forecasting: The Epidemia System, Christopher L. Merkord, Yi Liu, Abere Mihretie, Teklehaymanot Gebrehiwot, Worku Awoke, Estifanos Bayabil, Geoffrey M. Henebry, Gebeyaw T. Kassa, Mastewal Lake, Michael C. Wimberly Feb 2017

Integrating Malaria Surveillance With Climate Data For Outbreak Detection And Forecasting: The Epidemia System, Christopher L. Merkord, Yi Liu, Abere Mihretie, Teklehaymanot Gebrehiwot, Worku Awoke, Estifanos Bayabil, Geoffrey M. Henebry, Gebeyaw T. Kassa, Mastewal Lake, Michael C. Wimberly

GSCE Faculty Publications

Background: Early indication of an emerging malaria epidemic can provide an opportunity for proactive interventions. Challenges to the identification of nascent malaria epidemics include obtaining recent epidemiological surveillance data, spatially and temporally harmonizing this information with timely data on environmental precursors, applying models for early detection and early warning, and communicating results to public health officials. Automated web-based informatics systems can provide a solution to these problems, but their implementation in real-world settings has been limited.
Methods: The Epidemic Prognosis Incorporating Disease and Environmental Monitoring for Integrated Assessment (EPIDEMIA) computer system was designed and implemented to integrate disease surveillance with …

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Multi-Year Modis Active Fire Type Classification Over The Brazilian Tropical Moist Forest Biome, David P. Roy, S. S. Kumar Jan 2017

Multi-Year Modis Active Fire Type Classification Over The Brazilian Tropical Moist Forest Biome, David P. Roy, S. S. Kumar

GSCE Faculty Publications

The Brazilian Tropical Moist Forest Biome (BTMFB) spans almost 4 million km2 and is subject to extensive annual fires that have been categorized into deforestation, maintenance, and forest fire types. Information on fire types is important as they have different atmospheric emissions and ecological impacts. A supervised classification methodology is presented to classify the fire type of MODerate resolution Imaging Spectroradiometer (MODIS) active fire detections using training data defined by consideration of Brazilian government forest monitoring program annual land cover maps, and using predictor variables concerned with fuel flammability, fuel load, fire behavior, fire seasonality, fire annual frequency, proximity …

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Using Remote Sensing To Estimate Crop Water Use To Improve Irrigation Water Management, Arturo Reyes-Gonzalez Jan 2017

Using Remote Sensing To Estimate Crop Water Use To Improve Irrigation Water Management, Arturo Reyes-Gonzalez

Electronic Theses and Dissertations

Irrigation water is scarce. Hence, accurate estimation of crop water use is necessary for proper irrigation managements and water conservation. Satellite-based remote sensing is a tool that can estimate crop water use efficiently. Several models have been developed to estimate crop water requirement or actual evapotranspiration (ETa) using remote sensing. One of them is the Mapping EvapoTranspiration at High Resolution using Internalized Calibration (METRIC) model. This model has been compared with other methods for ET estimations including weighing lysimeters, pan evaporation, Bowen Ratio Energy Balance System (BREBS), Eddy Covariance (EC), and sap flow. However, comparison of METRIC model outputs to …

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Examination Of The Potential Of Structure-From-Motion Photogrammetry And Terrestrial Laser Scanning For Rapid Nondestructive Field Measurement Of Grass Biomass, Sam D. Cooper Jan 2017

Examination Of The Potential Of Structure-From-Motion Photogrammetry And Terrestrial Laser Scanning For Rapid Nondestructive Field Measurement Of Grass Biomass, Sam D. Cooper

Electronic Theses and Dissertations

Above ground biomass (AGB) is a parameter commonly used for assessment of grassland systems. While destructive sampling of AGB is highly accurate, it is time consuming and often precludes repeat temporal sampling or sampling in sensitive ecosystems. Consequently, a number of nondestructive techniques that relate grass structural properties to AGB have been developed. This study investigated the application of two recent technologies, Terrestrial Laser Scanning (TLS) and Structurefrom- Motion (SfM), in the development of rapid nondestructive AGB estimation of grassland plots. TLS and SfM volume metrics generated using a rasterized surface differencing method were linearly related to destructively measured total …

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Land Surface Phenologies And Seasonalities Using Cool Earthlight In Temperate And Tropical Croplands, Woubet Gashaw Alemu Jan 2017

Land Surface Phenologies And Seasonalities Using Cool Earthlight In Temperate And Tropical Croplands, Woubet Gashaw Alemu

Electronic Theses and Dissertations

In today’s world of increasing food insecurity due to more frequent and extreme events (droughts, floods), a comprehensive understanding of global cropland dynamics is critically needed. Land surface parameters derived from the passive microwave Advanced Microwave Scanning Radiometer on EOS (AMSR-E) and AMSR2 data enable monitoring of cropland dynamics and they can complement visible to near infrared (VNIR) and thermal infrared (TIR) data. Passive microwave data are less sensitive to atmospheric effects, cloud contamination, and solar illumination constraints resulting in finer temporal resolution suitable to track the temporal progression of cropland cover development compared to the VNIR data that has …

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Monitoring Pollen Counts And Pollen Allergy Index Using Satellite Observations In East Coast Of The United States, Murat Cagatay Kececi Jan 2017

Monitoring Pollen Counts And Pollen Allergy Index Using Satellite Observations In East Coast Of The United States, Murat Cagatay Kececi

Electronic Theses and Dissertations

Allergic diseases have become increasingly common over the world during the last four decades, and they are affecting millions of people. Pollination is an important process in the life cycle of plants. However, pollen exposure is associated with allergic diseases such as asthma and seasonal allergic rhinitis (hay fever). As a result, the total annual expenditure for asthma-associated morbidity is about $56 billion in the United States, and the overall cost of allergic diseases is over $18 billion annually. For allergic rhinitis, the annual medical cost is approximately $3.4 billion. The intensity and frequency of the pollen exposures can be …

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Normalization Of Pseudo-Invariant Calibration Sites For Increasing The Temporal Resolution And Long-Term Trending, Harika Vuppula Jan 2017

Normalization Of Pseudo-Invariant Calibration Sites For Increasing The Temporal Resolution And Long-Term Trending, Harika Vuppula

Electronic Theses and Dissertations

Given their low level of temporal, spatial, and spectral variability, Pseudo-Invariant Calibration Sites (PICS) have been increasingly desired as data sources for radiometric calibration of Earth imaging satellite sensors. The temporal resolution for PICS data acquired by any sensor is limited by the amount of time required for it to make subsequent passes over the site. Consequently, for any given PICS, it can take many years of imaging to develop a sufficient amount of cloud-free data to perform radiometric calibration; this can be especially problematic for sensors in their early years after launch. This thesis presents techniques to combine Landsat-8; …

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Landsat 5 Thematic Mapper Reflectance And Ndvi 27-Year Time Series Inconsistencies Due To Satellite Orbit Change, Hankui Zhang, David P. Roy Dec 2016

Landsat 5 Thematic Mapper Reflectance And Ndvi 27-Year Time Series Inconsistencies Due To Satellite Orbit Change, Hankui Zhang, David P. Roy

GSCE Faculty Publications

The Landsat 5 Thematic Mapper (TM) sensor provided the longest single mission terrestrial remote sensing data record but temporally sparse station keeping maneuvers meant that the Landsat 5 orbit changed over the 27 year mission life. Long-term Landsat 5 TM reflectance inconsistencies may be introduced by orbit change induced solar zenith variations combined with surface reflectance anisotropy, commonly described by the Bi-directional Reflectance Distribution Function (BRDF). This study quantifies the local overpass time and observed solar zenith angle changes for all the Landsat 5 TM images available at two latitudinally separated locations along the same north-south Landsat path (27) in …

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Characterizing Cropland Phenology In Major Grain Production Areas Of Russia, Ukraine, And Kazakhstan By The Synergistic Use Of Passive Microwave And Visible To Near Infrared Data, Woubet G. Alemu, Geoffrey M. Henebry Dec 2016

Characterizing Cropland Phenology In Major Grain Production Areas Of Russia, Ukraine, And Kazakhstan By The Synergistic Use Of Passive Microwave And Visible To Near Infrared Data, Woubet G. Alemu, Geoffrey M. Henebry

GSCE Faculty Publications

We demonstrate the synergistic use of surface air temperature retrieved from AMSR-E (Advanced Microwave Scanning Radiometer on Earth observing satellite) and two vegetation indices (VIs) from the shorter wavelengths of MODIS (MODerate resolution Imaging Spectroradiometer) to characterize cropland phenology in the major grain production areas of Northern Eurasia from 2003–2010. We selected 49 AMSR-E pixels across Ukraine, Russia, and Kazakhstan, based on MODIS land cover percentage data. AMSR-E air temperature growing degree-days (GDD) captures the weekly, monthly, and seasonal oscillations, and well correlated with station GDD. A convex quadratic (CxQ) model that linked thermal time measured as growing degree-days to …

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A Note On The Temporary Misregistration Of Landsat-8 Operational Land Imager (Oli) And Sentinel-2 Multi Spectral Instrument (Msi) Imagery, James Storey, David P. Roy, Jeffrey Masek, Ferran Gascon, Michael Choate Dec 2016

A Note On The Temporary Misregistration Of Landsat-8 Operational Land Imager (Oli) And Sentinel-2 Multi Spectral Instrument (Msi) Imagery, James Storey, David P. Roy, Jeffrey Masek, Ferran Gascon, Michael Choate

GSCE Faculty Publications

The Landsat-8 and Sentinel-2 sensors provide multi-spectral image data with similar spectral and spatial characteristics that together provide improved temporal coverage globally. Both systems are designed to register Level 1 products to a reference image framework, however, the Landsat-8 framework, based upon the Global Land Survey images, contains residual geolocation errors leading to an expected sensor-to-sensor misregistration of 38 m (2σ). These misalignments vary geographically but should be stable for a given area. The Landsat framework will be readjusted for consistency with the Sentinel-2 Global Reference Image, with completion expected in 2018. In the interim, users can measure Landsat-to-Sentinel tie …

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Characterization Of Landsat-7 To Landsat-8 Reflective Wavelength And Normalized Difference Vegetation Index Continuity, David P. Roy, V. Kovalskyy, Hankui Zhang, Eric F. Vermote, Lin Yan Dr., Sanath Sathyachandran Kumar, Alexey V. Egorov Nov 2016

Characterization Of Landsat-7 To Landsat-8 Reflective Wavelength And Normalized Difference Vegetation Index Continuity, David P. Roy, V. Kovalskyy, Hankui Zhang, Eric F. Vermote, Lin Yan Dr., Sanath Sathyachandran Kumar, Alexey V. Egorov

GSCE Faculty Publications

At over 40 years, the Landsat satellites provide the longest temporal record of space-based land surface observations, and the successful 2013 launch of the Landsat-8 is continuing this legacy. Ideally, the Landsat data record should be consistent over the Landsat sensor series. The Landsat-8 Operational Land Imager (OLI) has improved calibration, signal to noise characteristics, higher 12-bit radiometric resolution, and spectrally narrower wavebands than the previous Landsat-7 Enhanced Thematic Mapper (ETM +). Reflective wavelength differences between the two Landsat sensors depend also on the surface reflectance and atmospheric state which are difficult to model comprehensively. The orbit and sensing geometries …

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Canopy Height Estimation By Characterizing Waveform Lidar Geometry Based On Shape-Distance Metric, Eric Ariel L. Salas, Geoffrey M. Henebry Nov 2016

Canopy Height Estimation By Characterizing Waveform Lidar Geometry Based On Shape-Distance Metric, Eric Ariel L. Salas, Geoffrey M. Henebry

GSCE Faculty Publications

There have been few approaches developed for the estimation of height using waveform LiDAR data. Unlike any existing methods, we illustrate how the new Moment Distance (MD) framework can characterize the canopy height based on the geometry and return power of the LiDAR waveform without having to go through curve modeling processes. Our approach offers the possibilities of using the raw waveform data to capture vital information from the variety of complex waveform shapes in LiDAR. We assess the relationship of the MD metrics to the key waveform landmarks—such as locations of peaks, power of returns, canopy heights, and height …

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Urban–Rural Contrasts In Central-Eastern European Cities Using A Modis 4 Micron Time Series, Monika Tomaszewska, Geoffrey M. Henebry Nov 2016

Urban–Rural Contrasts In Central-Eastern European Cities Using A Modis 4 Micron Time Series, Monika Tomaszewska, Geoffrey M. Henebry

GSCE Faculty Publications

A primary impact of urbanization on the local climate is evident in the phenomenon recognized as the Urban Heat Island (UHI) effect. This urban thermal anomaly can increase the health risks of vulnerable populations to heat waves. The surface UHI results from emittance in the longer wavelengths of the thermal infrared; however, there are also urban anomalies that are detectable from radiance in the shorter wavelengths (3–5 micron) of the Middle Infrared (MIR). Radiance in the MIR can penetrate urban haze which frequently obscures urban areas by scattering visible and near infrared radiation. We analyzed seasonal and spatial variations in …

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Differential Heating In The Indian Ocean Differentially Modulates Precipitation In The Ganges And Brahmaputra Basins, Md Shahriar Pervez, Geoffrey M. Henebry Oct 2016

Differential Heating In The Indian Ocean Differentially Modulates Precipitation In The Ganges And Brahmaputra Basins, Md Shahriar Pervez, Geoffrey M. Henebry

GSCE Faculty Publications

Indo-Pacific sea surface temperature dynamics play a prominent role in Asian summer monsoon variability. Two interactive climate modes of the Indo-Pacific—the El Niño/Southern Oscillation (ENSO) and the Indian Ocean dipole mode—modulate the amount of precipitation over India, in addition to precipitation over Africa, Indonesia, and Australia. However, this modulation is not spatially uniform. The precipitation in southern India is strongly forced by the Indian Ocean dipole mode and ENSO. In contrast, across northern India, encompassing the Ganges and Brahmaputra basins, the climate mode influence on precipitation is much less. Understanding the forcing of precipitation in these river basins is vital …

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Rapid Land Cover Map Updates Using Change Detection And Robust Random Forest Classifiersrapid Land Cover Map Updates Using Change Detection And Robust Random Forest Classifiers, Konrad J. Wassels, Frans Van Den Bergh, David P. Roy, Brian P. Salmon, Karen C. Steenkemp, Bryan Macalister, Derick Swanepoel, Debbie Jewitt Oct 2016

Rapid Land Cover Map Updates Using Change Detection And Robust Random Forest Classifiersrapid Land Cover Map Updates Using Change Detection And Robust Random Forest Classifiers, Konrad J. Wassels, Frans Van Den Bergh, David P. Roy, Brian P. Salmon, Karen C. Steenkemp, Bryan Macalister, Derick Swanepoel, Debbie Jewitt

GSCE Faculty Publications

The paper evaluated the Landsat Automated Land Cover Update Mapping (LALCUM) system designed to rapidly update a land cover map to a desired nominal year using a pre-existing reference land cover map. The system uses the Iteratively Reweighted Multivariate Alteration Detection (IRMAD) to identify areas of change and no change. The system then automatically generates large amounts of training samples (n > 1 million) in the no-change areas as input to an optimized Random Forest classifier. Experiments were conducted in the KwaZulu-Natal Province of South Africa using a reference land cover map from 2008, a change mask between 2008 and …

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Separability Analysis Of Sentinel-2a Multi-Spectral Instrument (Msi) Data For Burned Area Discrimination, Haiyan Huang, David P. Roy, Luigi Boschetti, Hankui Zhang, Lin Yan Dr., Sanath Sathyachandran Kumar, Jose Gomez-Dans, Jian Li Oct 2016

Separability Analysis Of Sentinel-2a Multi-Spectral Instrument (Msi) Data For Burned Area Discrimination, Haiyan Huang, David P. Roy, Luigi Boschetti, Hankui Zhang, Lin Yan Dr., Sanath Sathyachandran Kumar, Jose Gomez-Dans, Jian Li

GSCE Faculty Publications

: Biomass burning is a global phenomenon and systematic burned area mapping is of increasing importance for science and applications. With high spatial resolution and novelty in band design, the recently launched Sentinel-2A satellite provides a new opportunity for moderate spatial resolution burned area mapping. This study examines the performance of the Sentinel-2A Multi Spectral Instrument (MSI) bands and derived spectral indices to differentiate between unburned and burned areas. For this purpose, five pairs of pre-fire and post-fire top of atmosphere (TOA reflectance) and atmospherically corrected (surface reflectance) images were studied. The pixel values of locations that were unburned in …

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Urban Heat Islands As Viewed By Microwave Radiometers And Thermal Time Indices, Lan H. Nguyen, Geoffrey M. Henebry Oct 2016

Urban Heat Islands As Viewed By Microwave Radiometers And Thermal Time Indices, Lan H. Nguyen, Geoffrey M. Henebry

GSCE Faculty Publications

Urban heat islands (UHIs) have been long studied using both ground-based observations of air temperature and remotely sensed thermal infrared (TIR) data. While ground-based observations lack spatial detail even in the occasional “dense” urban network, skin temperature retrievals using TIR data have lower temporal coverage due to revisit frequency, limited swath width, and cloud cover. Algorithms have recently been developed to retrieve near-surface air temperatures using microwave radiometer data, which enables characterization of UHIs in metropolitan areas, major conurbations, and global megacities at regional to continental scales using temporally denser time series than those that have been available from TIR …

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A Comparison Of Tropical Rainforest Phenology Retrieved From Geostationary (Seviri) And Polar-Orbiting (Modis) Sensors Across The Congo Basin, Dong Yan, Xiaoyang Zhang, Yunyue Yu, Wei Guo Aug 2016

A Comparison Of Tropical Rainforest Phenology Retrieved From Geostationary (Seviri) And Polar-Orbiting (Modis) Sensors Across The Congo Basin, Dong Yan, Xiaoyang Zhang, Yunyue Yu, Wei Guo

GSCE Faculty Publications

The seasonal and interannual dynamics of tropical rainforests play a critical role in the global carbon cycle and climate change. This paper retrieved and compared land surface phenology from observations acquired by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard geostationary satellites and the Moderate Resolution Imaging Spectroradiometer (MODIS) on polar-orbiting satellites over the Congo Basin. To achieve this,we first retrieved canopy greenness cycles (CGCs) and their transition timing from two-band enhanced vegetation index (EVI2) derived from SEVIRI and MODIS data between 2006 and 2013.We then assessed the influences of SEVIRI and MODIS data quality on the reconstruction of …

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An Automated Approach For Sub-Pixel Registration Of Landsat-8 Operational Land Imager (Oli) And Sentinel-2 Multi Spectral Instrument (Msi) Imagery, Lin Yan, David P. Roy, Hankui Zhang, Jian Li, Haiyan Huang Jun 2016

An Automated Approach For Sub-Pixel Registration Of Landsat-8 Operational Land Imager (Oli) And Sentinel-2 Multi Spectral Instrument (Msi) Imagery, Lin Yan, David P. Roy, Hankui Zhang, Jian Li, Haiyan Huang

GSCE Faculty Publications

Moderate spatial resolution satellite data from the Landsat-8 OLI and Sentinel-2A MSI sensors together offer 10 m to 30 m multi-spectral reflective wavelength global coverage, providing the opportunity for improved combined sensor mapping and monitoring of the Earth’s surface. However, the standard geolocated Landsat-8 OLI L1T and Sentinel-2A MSI L1C data products are currently found to be misaligned. An approach for automated registration of Landsat-8 OLI L1T and Sentinel-2A MSI L1C data is presented and demonstrated using contemporaneous sensor data. The approach is computationally efficient because it implements feature point detection across four image pyramid levels to identify a sparse …

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A Comparison Of Multiple Datasets For Monitoring Thermal Time In Urban Areas Over The U.S. Upper Midwest, Cole Krehbiel, Geoffrey M. Henebry Apr 2016

A Comparison Of Multiple Datasets For Monitoring Thermal Time In Urban Areas Over The U.S. Upper Midwest, Cole Krehbiel, Geoffrey M. Henebry

GSCE Faculty Publications

Traditional studies of urban climate used air temperature observations from local urban/rural weather stations in order to analyze the general pattern of higher temperatures in urban areas compared with corresponding rural regions, also known as the Urban Heat Island (UHI) effect. More recently, satellite remote sensing datasets of land surface temperature have been exploited to monitor UHIs. While closely linked, air temperature and land surface temperature (LST) observations do not measure the same variables. Here we analyze land surface temperature vs.air temperature-based characterization and seasonality of the UHI and the surface UHI (SUHI) from 2003 to 2012 over the …

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A General Method To Normalize Landsat Reflectance Data To Nadir Brdf Adjusted Reflectance, David P. Roy, Hankui Zhang, Junchang Ju, Jose Luis Gomez-Dans, Philip E. Lewis, Crystal Barker B. Schaaf, Qingsong Sun, Jian Li, Haiyan Huang, V. Kovalskyy Apr 2016

A General Method To Normalize Landsat Reflectance Data To Nadir Brdf Adjusted Reflectance, David P. Roy, Hankui Zhang, Junchang Ju, Jose Luis Gomez-Dans, Philip E. Lewis, Crystal Barker B. Schaaf, Qingsong Sun, Jian Li, Haiyan Huang, V. Kovalskyy

GSCE Faculty Publications

The Landsat satellites have been providing spectacular imagery of the Earth's surface for over 40 years. However, they acquire images at view angles ±7.5° from nadir that cause small directional effects in the surface reflectance. There are also variations with solar zenith angle over the year that can cause apparent change in reflectance even if the surface properties remain constant. When Landsat data from adjoining paths, or from long time series are used, a model of the surface anisotropy is required to adjust all Landsat observations to a uniform nadir view (primarily for visual consistency, vegetation monitoring, or detection of …

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Computationally Inexpensive Landsat 8 Operational Land Imager (Oli) Pansharpening, Hankui Zhang, David P. Roy Jan 2016

Computationally Inexpensive Landsat 8 Operational Land Imager (Oli) Pansharpening, Hankui Zhang, David P. Roy

GSCE Faculty Publications

Pansharpening algorithms fuse higher spatial resolution panchromatic with lower spatial resolution multispectral imagery to create higher spatial resolution multispectral images. The free-availability and systematic global acquisition of Landsat 8 data indicate an expected need for global coverage and so computationally efficient Landsat 8 pansharpening. This study adapts and evaluates the established, and relatively computationally inexpensive, Brovey and context adaptive Gram Schmidt component substitution (CS) pansharpening methods for application to the Landsat 8 15 m panchromatic and 30 m red, green, blue, and near-infrared bands. The intensity images used by these CS pansharpening methods are derived as a weighted linear combination …

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