Type of Presentation

Poster

Session Title

Remote sensing technology to monitor the short and long term dynamic of the Salish Sea

Description

Ocean colour remote sensing is a useful tool for monitoring marine ecosystem health through the detection of chlorophyll-a, a proxy for phytoplankton biomass. Phytoplankton are important to marine ecosystems as the base of the aquatic food web. The year 2015 displayed anomalously high chlorophyll-a concentrations in the Salish Sea.

Utilizing the Moderate Resolution Imaging Spectroradiometer (MODIS-Aqua) ocean colour satellite (1000m resolution), chlorophyll-a was characterized for 2015. The imagery was processed in order to correct for atmospheric contribution to the signal using a method developed specifically for the Salish Sea. Individual pixels were flagged in order to screen out incorrect or unusable elements, such as those where chlorophyll-a concentrations are overestimated (deemed above 60 mg/m3), the area is obscured by cloud, or the atmospheric correction has failed. Compared to previous years, 2015 displayed uncharacteristically few pixels with chlorophyll-a estimates in the Salish Sea, likely due to the the flagging threshold unaccustomed to such wide scale high chlorophyll-a concentrations, resulting in faulty loss of data.

To account for these flagged pixels, MODIS-Aqua imagery from 2015 of the Salish Sea was reprocessed with revised thresholds for the applied flags. The satellite chlorophyll-a measurements were evaluated in relation to in situ chlorophyll-a data collected by the Ocean Networks Canada (ONC) FerryBox project, citizen science chlorophyll-a data facilitated by the Pacific Salmon Foundation, and chlorophyll-a concentrations collected by DFO. Revising the thresholds and encorportaing in situ data will result in more pixels with chlorophyll-a for analysis.

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Reanalysis of satellite derived chlorophyll-a data for the Salish Sea

2016SSEC

Ocean colour remote sensing is a useful tool for monitoring marine ecosystem health through the detection of chlorophyll-a, a proxy for phytoplankton biomass. Phytoplankton are important to marine ecosystems as the base of the aquatic food web. The year 2015 displayed anomalously high chlorophyll-a concentrations in the Salish Sea.

Utilizing the Moderate Resolution Imaging Spectroradiometer (MODIS-Aqua) ocean colour satellite (1000m resolution), chlorophyll-a was characterized for 2015. The imagery was processed in order to correct for atmospheric contribution to the signal using a method developed specifically for the Salish Sea. Individual pixels were flagged in order to screen out incorrect or unusable elements, such as those where chlorophyll-a concentrations are overestimated (deemed above 60 mg/m3), the area is obscured by cloud, or the atmospheric correction has failed. Compared to previous years, 2015 displayed uncharacteristically few pixels with chlorophyll-a estimates in the Salish Sea, likely due to the the flagging threshold unaccustomed to such wide scale high chlorophyll-a concentrations, resulting in faulty loss of data.

To account for these flagged pixels, MODIS-Aqua imagery from 2015 of the Salish Sea was reprocessed with revised thresholds for the applied flags. The satellite chlorophyll-a measurements were evaluated in relation to in situ chlorophyll-a data collected by the Ocean Networks Canada (ONC) FerryBox project, citizen science chlorophyll-a data facilitated by the Pacific Salmon Foundation, and chlorophyll-a concentrations collected by DFO. Revising the thresholds and encorportaing in situ data will result in more pixels with chlorophyll-a for analysis.