Reanalysis of satellite derived chlorophyll-a data for the Salish Sea
Presentation Abstract
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.
Session Title
Remote sensing technology to monitor the short and long term dynamic of the Salish Sea
Conference Track
Habitat
Conference Name
Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)
Document Type
Event
Start Date
2016 12:00 AM
End Date
2016 12:00 AM
Location
2016SSEC
Type of Presentation
Poster
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Phytoplankton--Salish Sea (B.C. and Wash.); Ocean color--Salish Sea (B.C. and Wash.)--Remote sensing; Ocean color--Salish Sea (B.C. and Wash.)--Observation; Environmental monitoring--Remote sensing
Geographic Coverage
Salish Sea (B.C. and Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
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.
