Understanding how finescale ocean dynamics affect the boundary current system and mesoscale eddies in the Labrador Sea
Long-term (>20 years) observational activities are conducted in the Northwest Atlantic Ocean, monitoring the different branches of the Labrador Current system and the central Labrador Sea. Along the Newfoundland and Labrador (NL) Shelf, numerous hydrographic sections are surveyed regularly in the framework of the Atlantic Zone Monitoring Program (AZMP). An array of up to 10 moorings (since 2014) collects observations with high temporal resolution (<30 min) from the shallow shelf into the deep ocean (>3800m). This array thus monitors dynamics of the full boundary current system as part of the Overturning in the Subpolar Atlantic Program (OSNAP www.o-snap.org). In addition, one deep sea mooring in the central Labrador Sea observes flow and hydrography with high temporal resolution. All these observations show evidence of the rich spectrum of mesoscale and submesoscale dynamical processes that occur and which are in turn are key for subsequent processes such as carbon and oxygen uptake, primary productivity and ultimately have an impact on fisheries. Only few direct observations have been conducted with the aim to map fine scales in the Labrador Sea and almost all current knowledge has been derived from satellite data. As a matter of fact, one key outcome of observational and high-resolution modelling studies is, that the satellite data is too coarse and shows only very rough, if at all, agreement about mesoscale features..
The aim of the Labrador Sea mesoscale campaigns is to get a detailed view on the temporal and spatial scales of the mesoscale dynamics in selected areas and investigate their representation in SWOT retrievals. In-situ observations will be acquired using moored, ship based, and autonomous (underwater glider) observational platforms. This data will provide ground-truth for estimating the capabilities of SWOT in providing high-resolution spatial sampling of ocean topography in this subpolar, high latitude region.
The experiment comprises different campaigns, starting in the SWOT fast-sampling phase and continuing during the science data collection phase. To study processes over the NL Shelf, the AZMP multidisciplinary monitoring will be leveraged during the SWOT fast-sampling phase. It will include CTD, acoustic (echo-sounder and vessel mounted ADCP) and glider measurements. Processes in the open ocean will be studied within a three and a half weeks campaign aboard the R/V Maria S Merian in summer 2022. Ship measurements will be complemented with drifter releases, microstructure, plankton net sampling, validation trawls (for acoustics) and/or surface continuous measurements of biogeochemical properties.
The SWOT Labrador Sea mesoscale campaigns will allow gathering a deeper understanding of fine scale dynamical processes and their impacts on subpolar seas, including the Arctic freshwater pathways in the North Atlantic, an important contributor to the global climate system.
Institutes involved in the campaigns: Northwest Atlantic Fisheries Centre (NAFC), Fisheries and Oceans Canada (DFO); Helmholtz Centre for Ocean Research Kiel (GEOMAR).
Contact point for the study site: Frédéric Cyr (Frederic.Cyr@dfo-mpo.gc.ca).