Surface salinity anomaly over the eastern Gulf of Maine, the region where Scotian Shelf inflow first appears after rounding Cape Sable. Negative values are fresher than usual, which indicates a stronger inflow of cold fresh Scotian Shelf Water.
Usage
eastern_gom_salinity(
env_dat,
salinity = "SSS",
reference = c("climatology", "record", "none"),
name = "egom_salinity"
)Arguments
- env_dat
an
sfPOINT object with one row per location and time step, as datamatch's access functions return- salinity
name of the surface salinity column, in PSU
- reference
passed to
box_anomaly()- name
name for the new column
Details
Follows the approach of Grodsky et al. (2025), who showed that satellite surface salinity in the eastern Gulf tracks winter Scotian Shelf inflow and relates it to the coastal and interior pathways the water then takes. Their index is built from SMAP satellite salinity; this computes the same kind of quantity from whatever gridded salinity field you supply, so it is not a reproduction of their published series and should not be compared to it value for value.
Why this is the seasonal one
The signal is a winter one. Scotian Shelf Water arrives in the upper layers of the Gulf in winter, roughly six months after the late-summer deep influx of warm salty water. A whole-year mean mixes the two regimes together and dilutes the thing being measured, so restrict to winter months at the fetch, or subset afterwards, rather than reading an annual value as an inflow index.
References
Grodsky SA, Vandemark D, Levin J (2025). An eastern Gulf of Maine salinity index for monitoring winter Scotian Shelf inflow and its relation to coastal and interior pathways. Journal of Geophysical Research: Oceans 130(5). doi:10.1029/2024JC021891