ORIGINAL RESEARCH article
Front. Mar. Sci.
Sec. Coastal Ocean Processes
Volume 12 - 2025 | doi: 10.3389/fmars.2025.1672298
This article is part of the Research TopicApplication of Remote Sensing in Coastal Oceanic Processes Volume IIView all 6 articles
Evaluation of satellite-based sea surface salinity derived from two distinct spectral domains over the coastal waters of the St. Lawrence Estuary and Gulf
Provisionally accepted
Julien Laliberté1*
Guillaume Guénard1Jacqueline Dumas1Peter S. Galbraith1Sarah Hall2David Trossman3
Steve Vissault1- 1Fisheries and Oceans Canada, Ottawa, Canada
- 2Global Science and Technology, Greenbelt, Maryland, United States
- 3University of Maryland, College Park, United States
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Brightness Temperature is operationally used to retrieve Sea Surface Salinity (TB-SSS) over the global ocean, but is contaminated by land and sea ice in close proximity. Ocean Color can be used to retrieve SSS (OC-SSS) via the relation between color and salinity, but this relation is only valid over the coastal ocean with terrestrial influence. Important ecological areas exist where both spectral domains can provide SSS estimates. Here we compare these estimates over the St. Lawrence Estuary and Gulf in Eastern Canada, where a large collection of near-surface in situ salinity measurements is available. While TB-SSS faces a significant limitation in undersampling spatial variability, OC-SSS is predominantly hindered by cloud cover. Offshore, TB-SSS data are considerably more abundant than OC-SSS data, the latter of which are available only about 30% as often as the former. However, OC-SSS estimates extend into more nearshore areas, such as the St. Lawrence Estuary. Additionally, OC-SSS estimates are more accurate, with a root mean square difference of 0.46 g kg−1 compared to 0.79 g kg−1 for TB-SSS. We employed each of these satellite-derived SSS products to compare the pronounced freshwater pulse of 2017 and post-tropical storm Dorian of fall 2019, finding that short-lived events were better captured by the OC-SSS product. In contrast, the TB-SSS product offered more extensive temporal coverage but smoothed out such events. Our analyses underscore the need for higher-resolution satellite salinity sensors in coastal studies. In the mean-time, ocean color data resolves submesoscale features and can help enhance our understanding of these dynamic environments.
Keywords: Salinity, Ocean color remote sensing, Microwave remote sensing, coastal ocean, SMAP, CCI
Received: 24 Jul 2025; Accepted: 29 Sep 2025.
Copyright: © 2025 Laliberté, Guénard, Dumas, Galbraith, Hall, Trossman and Vissault. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Julien Laliberté, julien.laliberte@gmail.com
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.