Data on Oceanographic Conditions at the Surface of the St. Lawrence Estuary and Gulf, Mainly Derived from Satellite Remote Sensing.

This collection brings together several daily environmental variables covering the St. Lawrence Estuary and Gulf. The project aims to make the best available data on coastal environments accessible in a single repository, prioritizing the optimal balance between the quality of estimates, spatial resolution, temporal frequency, and the duration of the available data series. When satellite observations do not allow for a direct estimate of a variable, the best available reanalysis or data assimilation products are used.

All variables are presented on a common grid with a spatial resolution of one kilometre covering the St. Lawrence Estuary and Gulf, allowing them to be directly overlaid and used together in environmental analyses, numerical models, or time-series studies. Data can be easily extracted and integrated into major programming and spatial analysis software (R, Python, QGIS, ArcGIS, etc.) to provide context for observations or to drive environmental analyses. The datasets are updated automatically based on the availability of the various sources, with a delay that can generally be up to a few weeks. This collection is currently under development, and new variables will be added gradually to provide an increasingly comprehensive description of environmental conditions in coastal areas.

Available Variables:

• Chlorophyll-a concentration (mg m⁻³) : Daily estimates of chlorophyll-a concentration derived from satellite observations of ocean colour. The satellite data used originated from the "Ocean Colour Climate Change Initiative" (OC-CCI) program.

• Sea surface temperature (°C) : Daily sea surface temperature derived from infrared satellite observations from the GHRSST program. The observations are empirically corrected to improve their representativeness in the St. Lawrence Estuary and Gulf.

• Surface salinity (g kg⁻¹) : Daily estimates of surface salinity derived from satellite observations of water colour. The satellite data used originated from the "Ocean Colour Climate Change Initiative" (OC-CCI) program.

• Sea ice concentration (%) : Daily fraction of the sea surface covered by sea ice, based on maps from the Canadian Ice Service and interpolated onto the common grid.

• Depth of the mixing zone (m) : Daily depth of the oceanic mixing zone, derived from the GLORYS12 ocean reanalysis (Mercator Ocean). This variable represents the thickness of the surface layer homogenized by vertical mixing.

• Wind speed (m s⁻¹) : Daily average wind speed at 10 m above sea level, calculated from the MERRA-2 atmospheric reanalysis and interpolated onto a 1 km grid.

• Soon available - Photosynthetically active radiation (PAR) (mol photons m⁻² day⁻¹) : Daily amount of sunlight available for photosynthesis estimated from satellite observations of cloud cover using a correspondence table-based approach.

• Soon available - Photosynthetically active radiation from the Moon (PAR lunar) (mol photons m⁻² night⁻¹) : Daily estimates of photosynthetically active radiation from the Moon, calculated based on the lunar phases, the Moon's position, and cloud cover.

Dataset limitation: Do not use for navigation purposes.