The Use of Sentinel-3 Imagery to Monitor Cyanobacterial Blooms

• Main Author: Igor Ogashawara
• Format: Article
• Language: English
• Published: MDPI AG 2019-06-01
• Series: Environments
• Subjects: phycocyanin; chlorophyll-a; water quality; Lake Erie; cyanobacteria; bio-optical modeling
• Online Access: https://www.mdpi.com/2076-3298/6/6/60

Cyanobacterial harmful algal blooms (CHABs) have been a concern for aquatic systems, especially those used for water supply and recreation. Thus, the monitoring of CHABs is essential for the establishment of water governance policies. Recently, remote sensing has been used as a tool to monitor CHABs worldwide. Remote monitoring of CHABs relies on the optical properties of pigments, especially the phycocyanin (PC) and chlorophyll-<i>a</i> (chl-<i>a</i>). The goal of this study is to evaluate the potential of recent launch the Ocean and Land Color Instrument (OLCI) on-board the Sentinel-3 satellite to identify PC and chl-<i>a</i>. To do this, OLCI images were collected over the Western part of Lake Erie (U.S.A.) during the summer of 2016, 2017, and 2018. When comparing the use of traditional remote sensing algorithms to estimate PC and chl-<i>a</i>, none was able to accurately estimate both pigments. However, when single and band ratios were used to estimate these pigments, stronger correlations were found. These results indicate that spectral band selection should be re-evaluated for the development of new algorithms for OLCI images. Overall, Sentinel 3/OLCI has the potential to be used to identify PC and chl-<i>a</i>. However, algorithm development is needed.