Hyperspectral discrimination of floating mats of seagrass wrack and the macroalgae Sargassum in coastal waters of Greater Florida Bay using airborne remote sensing

Dierssen, Heidi M.; Chlus, Adam; Russell, Brandon

doi:10.1016/j.rse.2015.01.027

Cited by 127 publications

(97 citation statements)

References 43 publications

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“…Without concurrent field data to validate the satellite-based observations, two criteria were used to verify the detected MABs. First, aggregation of floating macroalgae under winds and currents is featured by thin slicks or small patches (Hu, Feng, Hardy, & Hochberg, 2015;Hu, Li, Chen, Ge, Muller-Karger, Liu, Yu, & He, 2010;Hu, Yang, Zhang, Chen, & He, 2014;Dierssen, Chlus, & Russell, 2015). Floating macroalgae slicks were thus delineated on Landsat and HJ-1 VB-FAH images (VB-FAH ≥ 0.025), and then visualized on their corresponding color-composite images (Fig.…”

Section: Mab Mapping Results and Discussionmentioning

confidence: 99%

Mapping macroalgal blooms in the Yellow Sea and East China Sea using HJ-1 and Landsat data: Application of a virtual baseline reflectance height technique

Xing

2016

Remote Sensing of Environment

139

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Several methods have been proposed in previous studies to map macroalgal blooms (MABs) in the Yellow Sea (YS) and East China Sea (ECS), yet some of the required spectral bands are not available on the new HJ-1 satellite sensors although they do provide optimal resolution and temporal coverage (30-m resolution with 2-day revisit frequency) for bloom mapping. In this study, an index of Virtual-Baseline Floating macroAlgae Height (VB-FAH) is proposed to use the green and red bands as the baseline to measure the height of the near-infrared (NIR) reflectance. Cross-sensor comparison with Landsat TM and ETM + data suggests that for several images evaluated here VB-FAH appears to be comparable to the previously proposed Floating Algae Index (FAI) even in the absence of a shortwave-infrared (SWIR) band. VB-FAH is applied to 30-m resolution TM and ETM + data for the YS during 1995-2006 and to HJ-1 data for the ECS during 2009-2014 to map MABs. Results show bloom history in the YS back to 1999 and early bloom occurrence in the ECS in winter and spring (e.g., February and March 2013). MABs are also found to extend to the ECS as far south as 26°N near Fujian Province and Taiwan, and as far east as the Kuroshio Current. These new findings provide important information for exploring the origins, causes, and consequences of MABs in the YS and ECS.

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Section: Mab Mapping Results and Discussionmentioning

confidence: 99%

Mapping macroalgal blooms in the Yellow Sea and East China Sea using HJ-1 and Landsat data: Application of a virtual baseline reflectance height technique

Xing

2016

Remote Sensing of Environment

139

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“…High backscattering from the underlying coral skeleton, combined with a sharp decrease in absorption by symbiont and host pigments in the far red, results in the rising reflectance at 700 nm also referred to as the red edge of reflectance common to vegetation [38]. Torres-Pérez et al [12] were able to discern variability in the magnitude of near infrared reflectance related to different species of coral.…”

Section: Reflectance Of Different Coral/symbiont Systemsmentioning

confidence: 99%

“…The relationship between integrated reflectance and symbiont concentration may prove useful to assess or monitor reef condition and the potential for bleaching. Such algorithms may be implemented using hyperspectral sensors from airborne platforms like the Portable Remote Imaging Spectrometer (PRISM) [1,38], proposed future satellite sensors, and through the use of underwater hyperspectral imagers [32,33,47,48]. However, the implementation of the algorithms will be complicated by the effects of the intervening water column, sea-surface, and atmosphere, as well as the spectral and spatial resolution of the sensor itself [24,35].…”

Section: Conclusion and Outlook For Remote Sensingmentioning

confidence: 99%

Spectral Reflectance of Palauan Reef-Building Coral with Different Symbionts in Response to Elevated Temperature

et al. 2016

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Spectral reflectance patterns of corals are driven largely by the pigments of photosynthetic symbionts within the host cnidarian. The warm inshore bays and cooler offshore reefs of Palau share a variety of coral species with differing endosymbiotic dinoflagellates (genus: Symbiodinium), with the thermally tolerant Symbiodinium trenchii (S. trenchii) (= type D1a or D1-4) predominating under the elevated temperature regimes inshore, and primarily Clade C types in the cooler reefs offshore. Spectral reflectance of two species of stony coral, Cyphastrea serailia (C. serailia) and Pachyseris rugosa (P. rugosa), from both inshore and offshore locations shared multiple features both between sites and to similar global data from other studies. No clear reflectance features were evident which might serve as markers of thermally tolerant S. trenchii symbionts compared to the same species of coral with different symbionts. Reflectance from C. serailia colonies from inshore had a fluorescence peak at approximately 500 nm which was absent from offshore animals. Integrated reflectance across visible wavelengths had an inverse correlation to symbiont cell density and could be used as a relative indicator of the symbiont abundance for each type of coral. As hypothesized, coral colonies from offshore with Clade C symbionts showed a greater response to experimental heating, manifested as decreased symbiont density and increased reflectance or "bleaching" than their inshore counterparts with S. trenchii. Although no unique spectral features were found to distinguish species of symbiont, spectral differences related to the abundance of symbionts could prove useful in field and remote sensing studies.

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“…PRISM offers high SNR (500:1 at 450 nm) and spectral resolution in the 380-600 nm range, which is useful for chlorophyll measurements [137,138]. Data collected with PRISM was also used to demonstrate the possibility of discriminating floating vegetation, such as seagrass and Sargassum based on spectral signature [139]. In the period 2013-2015, the HyspIRI Airborne Campaign collected data from five flights over California using AVIRIS and the MODIS/ASTER Airborne Simulator (MASTER) from a high altitude platform (NASA ER-2) to simulate the data that would be acquired by HyspIRI and to determine its appropriate sensor resolutions [138,140].…”

Section: Sensor Resolutionsmentioning

confidence: 99%

“…In the period 2013-2015, the HyspIRI Airborne Campaign collected data from five flights over California using AVIRIS and the MODIS/ASTER Airborne Simulator (MASTER) from a high altitude platform (NASA ER-2) to simulate the data that would be acquired by HyspIRI and to determine its appropriate sensor resolutions [138,140]. Various teams have explored the potential of HyspIRI to monitor inland waters and wetlands [26,136,141], coastal waters [139,142,143] and the open ocean [138,144]. A study was also conducted to assess whether HyspIRI data could enable improvements to the Atmospheric Removal Program (ATREM) atmospheric correction method [145].…”

Section: Sensor Resolutionsmentioning

confidence: 99%

Sensor Capability and Atmospheric Correction in Ocean Colour Remote Sensing

et al. 2015

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Accurate correction of the corrupting effects of the atmosphere and the water's surface are essential in order to obtain the optical, biological and biogeochemical properties of the water from satellite-based multi-and hyper-spectral sensors. The major challenges now for atmospheric correction are the conditions of turbid coastal and inland waters and areas in which there are strongly-absorbing aerosols. Here, we outline how these issues can be addressed, with a focus on the potential of new sensor technologies and the opportunities for the development of novel algorithms and aerosol models. We review hardware developments, which will provide qualitative and quantitative increases in spectral, spatial, radiometric and temporal data of the Earth, as well as measurements from other sources, such as the Aerosol Robotic Network for Ocean Color (AERONET-OC) stations, bio-optical sensors on Argo (Bio-Argo) floats and polarimeters. We provide an overview of the state of the art in atmospheric correction algorithms, highlight recent advances and discuss the possible potential for hyperspectral data to address the current challenges.

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Hyperspectral discrimination of floating mats of seagrass wrack and the macroalgae Sargassum in coastal waters of Greater Florida Bay using airborne remote sensing

Cited by 127 publications

References 43 publications

Mapping macroalgal blooms in the Yellow Sea and East China Sea using HJ-1 and Landsat data: Application of a virtual baseline reflectance height technique

Mapping macroalgal blooms in the Yellow Sea and East China Sea using HJ-1 and Landsat data: Application of a virtual baseline reflectance height technique

Spectral Reflectance of Palauan Reef-Building Coral with Different Symbionts in Response to Elevated Temperature

Sensor Capability and Atmospheric Correction in Ocean Colour Remote Sensing

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