Application of airborne imaging spectrometry system data to intertidal seaweed classification and mapping

Bajjouk, Touria; Guillaumont, Brigitte; Populus, Jacques

doi:10.1007/978-94-009-1659-3_67

Cited by 13 publications

(17 citation statements)

References 15 publications

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“…Potentially inaccurate input data include the spatial distribution of seaweed species, including small patches of seaweed not accurately represented by or missing from the original seaweed maps (Braud, 1974;Bajjouk et al, 1996), mixed seaweed beds containing more than one species, and any loose seaweed that had washed up on the shore near to measurement site. Although previous studies were used to produce an updated map for the present modelling study, an aerial survey coupled with further surface studies would reduce uncertainties in this area.…”

Section: Discussion Of Differencesmentioning

confidence: 99%

“…One in the early 1970s (Braud, 1974) combined aerial photographs and in situ observations obtained from diving and field measurements. The second study in the 1990s used both field and airborne spectrometers to map the seaweed and seagrass beds near Roscoff (Bajjouk et al, 1996). The published maps from these previous studies were used to construct a dedicated map for this work which was further validated by The vertical zonation of seaweed species is very distinct on rocky shores with each species often forming a belt at a certain elevation in the eulittoral zone (the area between the highest and the lowest tides) and also in the subtidal zone (the area extending below the zero of the marine charts).…”

Section: Seaweed Speciation and Site Bathymetrymentioning

confidence: 99%

“…Broadband cavity ringdown spectroscopy (BBCRDS) uses light from a pulsed broadband laser to measure the absorption spectrum of samples contained within a high finesse optical cavity (Bitter et al, 2005;Jones, 2003, 2009). In this case, the BBCRDS instrument was configured to detect molecular iodine using several of the I 2 molecule's B ← X absorption bands in the wavelength range 560-570 nm.…”

Section: Bbcrds Measurementsmentioning

confidence: 99%

“…BBCRDS absorption spectra were averaged to a time resolution of 5 minutes and the known absorptions due to ambient H 2 O (humidity meter) and O 4 (atmospheric oxygen concentration) were subtracted. The concentrations of I 2 and NO 2 were then retrieved from a multivariate fit of reference absorption cross sections to the structured features remaining in the sample's absorption spectrum using an analysis similar to that developed for DOAS (Platt, 1999;Jones, 2003, 2009). NO 2 cross sections were taken from Vandaele et al (1996) and were degraded to the 0.12 nm FWHM instrumental resolution.…”

Section: Bbcrds Measurementsmentioning

confidence: 99%

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Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff

et al. 2010

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Abstract. Iodine emissions from the dominant six macroalgal species in the coastal regions around Roscoff, France, have been modelled to support the Reactive Halogens in the Marine Boundary Layer Experiment (RHaMBLe) undertaken in September 2006. A two-dimensional model is used to explore the relationship between geographically resolved regional emissions (based on maps of seaweed beds in the area and seaweed I 2 emission rates previously measured in the laboratory) and in situ point and line measurements of I 2 performed respectively by a broadband cavity ringdown spectroscopy (BBCRDS) instrument sited on the shoreline and a long-path differential optical absorption spectroscopy (LP-DOAS) instrument sampling over an extended light path to an off-shore island. The modelled point and line I 2 concentrations compare quantitatively with BBCRDS and LP-DOAS measurements, and provide a link between emission fields and the different measurement geometries used to quantify atmospheric I 2 concentrations during RHaMBLe. Total I 2 emissions over the 100 km 2 region around Roscoff are calculated to be 1.7×10 19 molecules per second during the lowest tides.During the night, the model replicates I 2 concentrations up to 50 pptv measured along the LP-DOAS instrument's line of sight, and predicts spikes of several hundred pptv in certain conditions. Point I 2 concentrations up to 50 pptv are also calculated at the measurement site, in broad agreementCorrespondence to: R. J. Leigh (r.j.leigh@leicester.ac.uk) with the BBCRDS observations. Daytime measured concentrations of I 2 at the site correlate with modelled production and transport processes. However substantial recycling of the photodissociated I 2 is required for the model to quantitatively match measured concentrations. This result corroborates previous modelling of iodine and NO x chemistry in the semi-polluted marine boundary layer which proposed a mechanism for recycling I 2 via the formation, transport and subsequent reactions of the IONO 2 reservoir compound.The methodology presented in this paper provides a tool for linking spatially distinct measurements to inhomogeneous and temporally varying emission fields.

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Section: Discussion Of Differencesmentioning

confidence: 99%

Section: Seaweed Speciation and Site Bathymetrymentioning

confidence: 99%

Section: Bbcrds Measurementsmentioning

confidence: 99%

Section: Bbcrds Measurementsmentioning

confidence: 99%

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Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff

et al. 2010

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“…Aquatic and littoral vegetation have been mapped to species or community level [2,3,4,5] by utilising their reflectance differences in the visible region in classifications of casi (Compact Airborne Spectrographic Imager) image data. Algal classes can be taxonomically identified from the absorbance features produced by their characteristic accessory pigments [6].…”

Section: Introductionmentioning

confidence: 99%

Seagrass species: are they spectrally distinct?

Fyfe

Dekker

IGARSS 2001. Scanning the Present and Resolving the Future. Proceedings. IEEE 2001 International Geoscience and Remote Sensing

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The spectral reflectance of 3 species of seagrass was measured in different habitats at 3 estuaries in southeastern Australia during each of the 4 seasons of 2000. Seagrass species were spectrally distinct regardless of whether the leaves were fouled by epibionts even though spatial and temporal variability in reflectance was observed within each species. The visible wavelengths that penetrate water fortunately coincide with the regions of maximum absorption by plant photosynthetic and accessory pigments. Mapping of benthic plants to species level is possible using a hyperspectral sensor that has narrow bands centred on pigment-related spectral features in the visible, e.g. the programmable wavebands of the CASI (Compact Airborne Spectrographic Imager).

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Using object‐based image analysis with multi‐temporal aerial imagery and LiDAR to detect change in temperate intertidal habitats

Lightfoot

Scott

Fitzsimmons

2020

Aquatic Conservation

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Intertidal habitat maps are needed at both fine and coarse scales to monitor change and inform conservation and management, but current methods of field survey and expert interpretation of aerial imagery can be time‐consuming and subjective. Object‐based image analysis (OBIA) of remote sensing data is increasingly employed for producing habitat or land cover maps. Users create automated workflows to segment imagery, creating ecologically meaningful objects, which are then classified based on their spectral or geometric properties, relationships to other objects and contextual data. This study evaluates the change‐detection capability of OBIA in the intertidal environment by developing and comparing two OBIA methods for quantifying change in extent and distribution of habitats from freely available multi‐temporal aerial imagery and LiDAR data. Despite considerable variability in the data, pre‐ and post‐classification change detection methods had sufficient accuracy (mean overall accuracy from 70.5 to 82.6%) to monitor deviation from a background level of natural environmental fluctuation. This insight into spatial and temporal patterns of natural cyclical change and their detectability by OBIA could inform use of remote sensing for regular, rapid coastal assessment, providing an alert system to direct survey resources to areas of ecologically relevant change.

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Application of airborne imaging spectrometry system data to intertidal seaweed classification and mapping

Cited by 13 publications

References 15 publications

Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff

Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff

Seagrass species: are they spectrally distinct?

Using object‐based image analysis with multi‐temporal aerial imagery and LiDAR to detect change in temperate intertidal habitats

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