John D. Hedley
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View article: Neutral lines and model-measurement closure in oceanic polarized light fields
Neutral lines and model-measurement closure in oceanic polarized light fields Open
The polarization state of light in the maritime environment has untapped potential to reveal properties of the material constituents of the water column. Consequently, understanding the formation of polarization features is important for r…
View article: Neutral Lines and Model-Measurement Closure in Oceanic Polarized Light Fields
Neutral Lines and Model-Measurement Closure in Oceanic Polarized Light Fields Open
The polarization state of light in the maritime environment has untapped potential to reveal properties of the material constituents the water column. Consequentially, understanding the formation of polarization features is important for r…
View article: Optical closure in highly absorptive coastal waters: significance of inelastic scattering processes
Optical closure in highly absorptive coastal waters: significance of inelastic scattering processes Open
In hydrological optics, “optical closure” means consistency between the apparent optical properties (AOPs) determined from radiometric measurements and those derived from radiative transfer modelling based on concurrently measured inherent…
View article: Optical closure in highly absorptive coastal waters: significance of inelastic scattering processes
Optical closure in highly absorptive coastal waters: significance of inelastic scattering processes Open
In hydrological optics, "optical closure" means consistency between the apparent optical properties (AOPs) determined from radiometric measurements and those derived from radiative transfer modelling based on concurrently measured Inherent…
View article: The effects of surface roughness on the calculated, spectral, conical–conical reflectance factor as an alternative to the bidirectional reflectance distribution function of bare sea ice
The effects of surface roughness on the calculated, spectral, conical–conical reflectance factor as an alternative to the bidirectional reflectance distribution function of bare sea ice Open
The conical–conical reflectance factor (CCRF) has been calculated as an alternative to the bidirectional reflectance distribution function (BRDF) for three types of bare sea ice with varying surface roughness (σ= 0.1–10) and ice thicknesse…
View article: Comment on tc-2021-366
Comment on tc-2021-366 Open
Abstract. The Bidirectional Reflectance Distribution Function (BRDF) has been calculated for three types of bare sea ice with varying surface roughness (σ = 0.1–10 cm) and ice thicknesses (50–2000 cm) over an incident solar irradiance wave…
View article: The effects of surface roughness on the spectral (300–1400 nm) bidirectional reflectance distribution function (BRDF) of bare sea ice
The effects of surface roughness on the spectral (300–1400 nm) bidirectional reflectance distribution function (BRDF) of bare sea ice Open
The Bidirectional Reflectance Distribution Function (BRDF) has been calculated for three types of bare sea ice with varying surface roughness (σ = 0.1–10 cm) and ice thicknesses (50–2000 cm) over an incident solar irradiance wavelength ran…
View article: The effects of surface roughness on the spectral (300-1400 nm) bidirectional reflectance distribution function (BRDF) of sea ice
The effects of surface roughness on the spectral (300-1400 nm) bidirectional reflectance distribution function (BRDF) of sea ice Open
Please cite the following publication when using the data: Lamare, M. L., Hedley, J. D., and King, M. D.: The effects of surface roughness on the calculated, spectral, conical–conical reflectance factor as an alternative to the bidirectio…
View article: The effects of surface roughness on the spectral (300-1400 nm) bidirectional reflectance distribution function (BRDF) of sea ice
The effects of surface roughness on the spectral (300-1400 nm) bidirectional reflectance distribution function (BRDF) of sea ice Open
Please cite the following publication when using the data: Lamare, M. L., Hedley, J. D., and King, M. D.: The effects of surface roughness on the calculated, spectral, conical–conical reflectance factor as an alternative to the bidirectio…
View article: ICESat-2 Marine Bathymetry: Extraction, Refraction Adjustment and Vertical Accuracy as a Function of Depth in Mid-Latitude Temperate Contexts
ICESat-2 Marine Bathymetry: Extraction, Refraction Adjustment and Vertical Accuracy as a Function of Depth in Mid-Latitude Temperate Contexts Open
Nearshore bathymetric data are used in many coastal monitoring applications, but acquisition conditions can be challenging. Shipborne surveys are prone to the risk of grounding in shallow waters, and scheduled airborne surveys often fail t…
View article: Seagrass Depth Distribution Mirrors Coastal Development in the Mexican Caribbean – An Automated Analysis of 800 Satellite Images
Seagrass Depth Distribution Mirrors Coastal Development in the Mexican Caribbean – An Automated Analysis of 800 Satellite Images Open
The seagrass Thalassia testudinum is the dominant habitat-builder in coastal reef lagoons of the Caribbean, and provides vital ecosystem services including coastal protection and carbon storage. We used a remote sensing methodology to map …
View article: Optical backscattering and linear polarization properties of the colony forming cyanobacterium Microcystis
Optical backscattering and linear polarization properties of the colony forming cyanobacterium Microcystis Open
Light scattering characteristics of the cyanobacterium Microcystis are investigated with numerical models for sphere aggregates. During summer bloom seasons, Microcystis is prevalent in many inland waters across the globe. Monitoring conce…
View article: Bathymetric extraction from ICESAT-2 Advanced Topographic Laser Altimeter System photon returns: Depth penetration in diverse geophysical contexts.
Bathymetric extraction from ICESAT-2 Advanced Topographic Laser Altimeter System photon returns: Depth penetration in diverse geophysical contexts. Open
<p>Bathymetric measurement using remotely sensed data acquired in shallow-water marine contexts generally incurs challenges regardless of acquisition method. Multibeam sonar can be challenged with respect to survey vessel access and …
View article: Influence of Three-Dimensional Coral Structures on Hyperspectral Benthic Reflectance and Water-Leaving Reflectance
Influence of Three-Dimensional Coral Structures on Hyperspectral Benthic Reflectance and Water-Leaving Reflectance Open
Shading and inter-reflections created by the three-dimensional coral canopy structure play an important role on benthic reflectance and its propagation above the water. Here, a plane parallel model was coupled with a three-dimensional radi…
View article: Remote Sensing of Coral Bleaching Using Temperature and Light: Progress towards an Operational Algorithm
Remote Sensing of Coral Bleaching Using Temperature and Light: Progress towards an Operational Algorithm Open
The National Oceanic and Atmospheric Administration’s Coral Reef Watch program developed and operates several global satellite products to monitor bleaching-level heat stress. While these products have a proven ability to predict the onset…
View article: Remote Sensing of Seagrass Leaf Area Index and Species: The Capability of a Model Inversion Method Assessed by Sensitivity Analysis and Hyperspectral Data of Florida Bay
Remote Sensing of Seagrass Leaf Area Index and Species: The Capability of a Model Inversion Method Assessed by Sensitivity Analysis and Hyperspectral Data of Florida Bay Open
The capability for mapping two species of seagrass, Thalassia testudinium and Syringodium filiforme, by remote sensing using a physics based model inversion method was investigated. The model was based on a three-dimensional canopy model c…
View article: Implications of sensor design for coral reef detection: Upscaling ground hyperspectral imagery in spatial and spectral scales
Implications of sensor design for coral reef detection: Upscaling ground hyperspectral imagery in spatial and spectral scales Open
Remote sensing offers a potential tool for large scale environmental surveying and monitoring. However, remote observations of coral reefs are difficult especially due to the spatial and spectral complexity of the target compared to sensor…
View article: Remote Sensing of Coral Reefs for Monitoring and Management: A Review
Remote Sensing of Coral Reefs for Monitoring and Management: A Review Open
Coral reefs are in decline worldwide and monitoring activities are important for assessing the impact of disturbance on reefs and tracking subsequent recovery or decline. Monitoring by field surveys provides accurate data but at highly loc…
View article: Comparison of Two Independent Mapping Exercises in the Primeiras and Segundas Archipelago, Mozambique
Comparison of Two Independent Mapping Exercises in the Primeiras and Segundas Archipelago, Mozambique Open
Production of coral reef habitat maps from high spatial resolution multispectral imagery is common practice and benefits from standardized accuracy assessment methods and many informative studies on the merits of different processing algor…
View article: Appendix D. Tables showing mean frequency of abundance of each taxon within each benthic community around St. John and St. Thomas and a Bray-Curtis dissimilarity matrix between habitats and the table showing the five taxa with the largest influence on the Bray-Curtis dissimilarity between each pair of habitats.
Appendix D. Tables showing mean frequency of abundance of each taxon within each benthic community around St. John and St. Thomas and a Bray-Curtis dissimilarity matrix between habitats and the table showing the five taxa with the largest influence on the Bray-Curtis dissimilarity between each pair of habitats. Open
Tables showing mean frequency of abundance of each taxon within each benthic community around St. John and St. Thomas and a Bray-Curtis dissimilarity matrix between habitats and the table showing the five taxa with the largest influence on…
View article: Appendix C. Details of statistical techniques used to model coral reef beta diversity: model framework, selection and diagnostics, models of covariance, calculating the distance between data points, and estimates of coefficients.
Appendix C. Details of statistical techniques used to model coral reef beta diversity: model framework, selection and diagnostics, models of covariance, calculating the distance between data points, and estimates of coefficients. Open
Details of statistical techniques used to model coral reef beta diversity: model framework, selection and diagnostics, models of covariance, calculating the distance between data points, and estimates of coefficients.
View article: Appendix B. A description of protocol for calculation of wave exposure.
Appendix B. A description of protocol for calculation of wave exposure. Open
A description of protocol for calculation of wave exposure.
View article: Appendix A. Habitat maps of St. John and St. Thomas.
Appendix A. Habitat maps of St. John and St. Thomas. Open
Habitat maps of St. John and St. Thomas.
View article: Derivation of High-Resolution Bathymetry from Multispectral Satellite Imagery: A Comparison of Empirical and Optimisation Methods through Geographical Error Analysis
Derivation of High-Resolution Bathymetry from Multispectral Satellite Imagery: A Comparison of Empirical and Optimisation Methods through Geographical Error Analysis Open
The high importance of bathymetric character for many processes on reefs means that high-resolution bathymetric models are commonly needed by marine scientists and coastal managers. Empirical and optimisation methods provide two approaches…
View article: A Method to Analyze the Potential of Optical Remote Sensing for Benthic Habitat Mapping
A Method to Analyze the Potential of Optical Remote Sensing for Benthic Habitat Mapping Open
Quantifying the number and type of benthic classes that are able to be spectrally identified in shallow water remote sensing is important in understanding its potential for habitat mapping. Factors that impact the effectiveness of shallow …
View article: BENTHIC HABITAT MAPPING AND BIODIVERSITY ANALYSIS IN THE PRIMEIRAS AND SEGUNDAS ARCHIPELAGO RESERVE
BENTHIC HABITAT MAPPING AND BIODIVERSITY ANALYSIS IN THE PRIMEIRAS AND SEGUNDAS ARCHIPELAGO RESERVE Open
The Primeiras and Segundas Archipelago Reserve is a recently established marine protected area, the largest in Africa, located in the waters of Northern Mozambique. This protected area is of significant local economic importance and global…