Sensitivity of a Satellite Algorithm for Harmful Algal Bloom Discrimination to the Use of Laboratory Bio-optical Data for Training

Martinez-Vicente, V; Kurekin, A; Sa, C; Brotas, V; Amorim, AL; Veloso, V; Lin, J; Miller, PI. 2020 Sensitivity of a Satellite Algorithm for Harmful Algal Bloom Discrimination to the Use of Laboratory Bio-optical Data for Training. Frontiers in Marine Science, 7. https://doi.org/10.3389/fmars.2020.582960

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Official URL: http://dx.doi.org/10.3389/fmars.2020.582960

Abstract/Summary

Early detection of dense harmful algal blooms (HABs) is possible using ocean colour remote sensing. Some algorithms require a training dataset, usually constructed from satellite images with a priori knowledge of the existence of the bloom. This approach can be limited if there is a lack of in situ observations, coincident with satellite images. A laboratory experiment collected biological and bio-optical data from a culture of Karenia mikimotoi, a harmful phytoplankton dinoflagellate. These data showed characteristic signals in chlorophyll-specific absorption and backscattering coefficients. The bio-optical datafromthecultureandabio-opticalmodelwereusedtoconstructatrainingdatasetfor an existing statistical classifier. MERIS imagery over the European continental shelf were processed with the classifier using different training datasets. The differences in positive ratesofdetectionofK. mikimotoi betweenusinganalgorithmtrainedwithpurelymanually selected areas on satellite images and using laboratory data as training was overall <1%. The difference was higher, <15%, when using modeled optical data rather than laboratorydata,withpotentialforimprovementiflocalaveragechlorophyllconcentrations are used. Using a laboratory-derived training dataset improved the ability of the algorithm to distinguish high turbidity from high chlorophyll concentrations. However, additional in situ observations of non-harmful high chlorophyll blooms in the area would improve testing of the ability to distinguish harmful from non-harmful high chlorophyll blooms. This approach can be expanded to use additional wavelengths, different satellite sensors and different phytoplankton genera.

Item Type: Publication - Article
Additional Keywords: Keywords: phytoplankton, English channel, MERIS, optical backscattering, Karenia mikimotoi, harmful algal blooms, ocean color
Divisions: Plymouth Marine Laboratory > Science Areas > Earth Observation Science and Applications
Depositing User: S Hawkins
Date made live: 15 Dec 2020 10:16
Last Modified: 15 Dec 2020 10:16
URI: http://plymsea.ac.uk/id/eprint/9088

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