XXII ISPRS Congress 2012: Technical Commission VIII

Shortis, M.; Shimoda, H.; Cho, K.

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Multivolume work

Persistent identifier:: 1663813779

Title:: XXII ISPRS Congress 2012

Sub title:: Melbourne, Australia, 25 August-1 September 2012

Year of publication:: 2013

Place of publication:: Red Hook, NY

Publisher of the original:: Curran Associates, Inc.

Identifier (digital):: 1663813779

Language:: English

Additional Notes:: Kongress-Thema: Imaging a sustainable future

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Document type:: Multivolume work

Volume

Persistent identifier:: 1663822514

Title:: Technical Commission VIII

Scope:: 590 Seiten

Year of publication:: 2014

Place of publication:: Red Hook, NY

Publisher of the original:: Curran Associates, Inc.

Identifier (digital):: 1663822514

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(39,B8)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist ermittelt.; Literaturangaben

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Shortis, M.; Shimoda, H.; Cho, K.

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [VIII/6: Agriculture, Ecosystems and Bio-Diversity]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: SPECTRAL CHARACTERISTICS OF SELECTED HERMATYPIC CORALS FROM GULF OF KACHCHH, INDIA Nandini Ray Chaudhury

Document type:: Multivolume work

Structure type:: Chapter

SPECTRAL CHARACTERISTICS OF SELECTED HERMATYPIC CORALS FROM GULF OF KACHCHH, INDIA Nandini Ray Chaudhury EHD/ABHG/EPSA, Space Applications Centre, ISRO, Ahmedabad — 380015 — nandinire@sac.isro.gov.in Commission VIII, WG VIII/6 KEY WORDS: Ecosystem, Hyper spectral, Multispectral, Image, Identification ABSTRACT: Hermatypic, scleractinian corals are the most important benthic substrates in a coral reef ecosystem. The existing, high (spatial) resolution, broad-band, multi-spectral, space-borne sensors have limited capability to spatially detect and spectrally discriminate coral substrates. In situ hyperspectral signatures of eight coral targets were collected with the help of Analytical Spectral Devices FieldSpec spectroradiometer from Paga and Laku Point reefs of Gulf of Kachchh, India to study the spectral behaviour of corals. The eight coral targets consisted of seven live corals representing four distinct colony morphologies and one bleached coral target. The coral spectra were studied over a continuous range of 350 to 1350 nm. The corals strongly reflected in the NIR and MIR regions with regional central maximas located at 820 and 1070 nm respectively. In the visible region the live coral spectra conformed to “brown mode” of coral reflectance with triple-peaked pattern at 575, 600 and 650 nm. All coral spectra are characterized with two distinct absorption features: chlorophyll absorption at 675 nm and water absorption at 975 nm. The live and the bleached corals get distinguished in the visible region over 400 to 600 nm region. Water column over the targets modifies the spectral shape and magnitude. First and second-order derivatives help in identifying spectral windows to distinguish live and bleached corals. 1. INTRODUCTION Worldwide, hermatypic or reef-building corals occupy a keystone position in the overall functioning of reef ecosystem. Live coral cover of a reef habitat is one of the most widely accepted parameters of coral reef health (Green et al. 2000). Space-borne, optical remote sensing has sensor limitations in automated extraction of live coral cover parameter from space data. Digital delineation of this parameter has so far mostly used the expert knowledge of local reef systems in terms of specific geomorphological features and associated benthic classes (Hochberg and Atkinson, 2003). The existing, medium to high resolution, broadband, multi-spectral sensors have limited capabilities to provide synoptic data on live coral cover at community level. Poor penetration of sunlight and low signal to noise ratio of backscattered reflectance from deeper reef habitats are considered to be the major limiting factors to the performance of these sensors (Green et al. 2000). Therefore, live coral cover assessment through space-based imaging has been successfully confined to emergent, shallow, reef flat environments preferably at low tides. Relative abundance of reef biota and litho-substrates at different bathymetric depths with varying water column (i.e. depth, quality, etc.) add high degree of natural variability to coral reefs as optically complex, shallow water, remote sensing targets. This poses significant challenge in remote assessment of reef- sale biodiversity in terms of spatial detection and spectral characterization of individual corals at colony scale. As an underwater remote sensing target, coral reefs appear as Aes of diverse “substrates” or “bottom types" when viewed Tom the space (Hochberg et al. 2003). Spectral nature of the space-borne data has been recognized as the basic link between coral reef substrates and remotely sensed images (Hochberg and Atkinson, 2003). Substrate detection and quantification efforts have applied a deterministic, in situ data based, “reef-up” approach which often use proximal remote sensing of corals and other reef benthos. This approach calls for spectral cataloguing to identify distinct spectral features of a substrate. In situ reef-up approach has demonstrated the potential applications of field spectroscopy and hyperspectral analyses to characterize the reflectance properties of individual reef substrates which usually comprise an image (Goodman and Ustin, 2002). In situ hyperspectral signatures of corals and other reef benthos obtained with the help of portable field spectroradiometers have mostly been used for spectral discrimination of reef substrates (Hochberg and Atkinson, 2000, Hochberg et al. 2003, Hochberg and Atkinson, 2003, Kutser et al. 2003) and for health of corals (Holden and LeDrew, 1998; 1999; Clark et al. 2000). In situ reef spectra have been also used as input to simulate top-of- atmosphere spectral reflectance using radiative transfer models (Lubin et al. 2001). In situ spectral reflectance of corals per se has been recognized as a fundamental parameter in coral reef remote sensing (Hochberg et al. 2004). Spectral characteristics of coral organisms at colony or at community level have been correlated primarily with coral pigments, fluorescence and colony morphology (Hedley and Mumby, 2002; Hochberg et al., 2004; Joyce and Phinn, 2002 and 2003). Broad-band, multi-spectral signatures obtained from image-pixels of high (spatial) resolution Indian Remote Sensing (IRS) satellite

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