EK60 Water Column Sonar Data Collected During AR21

Cruise AR21 on RV Neil Armstrong (EK60). This cruise is the fourth cruise to the Irminger Sea Global Node of the National Science
Foundation’s Ocean Observatories Initiative (OOI; http://www.oceanobservatories.org). The
Irminger Sea Global Node includes an array of four moorings and a combination of
patrol and profiling gliders deployed off the southeast tip of Greenland, close to 39°W, 60°N. The location is one characterized by strong air-sea interaction and winter-time
water mass formation. It is also a location at an important location of the large-scale global
thermohaline circulation where freshening of the water column has been observed, and the data
from the array will contribute to improved understanding of the impact of climate variability and
change on the physics, chemistry, and biology of the ocean. The combination of the moored
array and the gliders will enable investigation of the role of processes at mesoscale and submesoscale
horizontal length scales. At the same time, the moored array and gliders will sample
the full water column, from the sea floor to the sea surface and the surface mooring will provide
unique new observations of surface meteorology and air-sea fluxes.
This Irminger Sea Global Node deployment cruise (Irminger-4) has the following primary
objectives: deployment of a new Surface Mooring (GI01SUMO), deployment of a new Profiler
Mooring (GI02HYPM), deployment of two new Flanking Moorings (GI03FLMA, GI03FLMB),
deployment of new Irminger Sea mobile assets (GI05MOAS) with the deployment of gliders
tasked to patrol within and around the moored array, recovery of the Surface Mooring, Profiler
Mooring, and Flanking Moorings set in July 2016, and CTD casts with water sampling at both for
instrument calibration and to further characterize the region of the mooring sites.
The intent is to deploy the fourth set of moorings before recovering the previously deployed third
set of moorings. This is done to obtain data sets invaluable to the process of intercalibrating the
moored instrumentation. Because of this and because the intent is to have future mooring
operations to be conducted in close proximity to moorings in the water, the site locations for
both the first and second deployments were identified during the bathymetric survey on the first
cruise in September 2014.