The Northwest Tropical Atlantic Station (NTAS): NTAS-19 Mooring Turnaround Cruise Report Cruise On Board RV Ronald H. Brown October 14 - November 1, 2020

Abstract

The Northwest Tropical Atlantic Station (NTAS) was established to address the need for accurate air-sea flux estimates and upper ocean measurements in a region with strong sea surface temperature anomalies and the likelihood of significant local air–sea interaction on interannual to decadal timescales. The approach is to maintain a surface mooring outfitted for meteorological and oceanographic measurements at a site near 15°N, 51°W by successive mooring turnarounds. These observations will be used to investigate air–sea interaction processes related to climate variability. This report documents recovery of the NTAS-18 mooring and deployment of the NTAS-19 mooring at the same site. Both moorings used Surlyn foam buoys as the surface element. These buoys were outfitted with two Air–Sea Interaction Meteorology (ASIMET) systems. Each system measures, records, and transmits via Argos satellite the surface meteorological variables necessary to compute air–sea fluxes of heat, moisture and momentum. The upper 160 m of the mooring line were outfitted with oceanographic sensors for the measurement of temperature, salinity and velocity. Deep ocean temperature and salinity are measured at approximately 38 m above the bottom. The mooring turnaround was done on the National Oceanic and Atmospheric Administration (NOAA) Ship Ronald H. Brown, Cruise RB-20-06, by the Upper Ocean Processes Group of the Woods Hole Oceanographic Institution. The cruise took place between 14 October and 1 November 2020. The NTAS-19 mooring was deployed on 22 October, with an anchor position of about 14° 49.48° N, 51° 00.96° W in 4985 m of water. A 31-hour intercomparison period followed, during which satellite telemetry data from the NTAS-19 buoy and the ship’s meteorological sensors were monitored. The NTAS-18 buoy, which had gone adrift on 28 April 2020, was recovered on 20 October near 13° 41.96° N, 58° 38.67° W. This report describes these operations, as well as other work done on the cruise and some of the pre-cruise buoy preparations.