The Northwest Tropical Atlantic Station (NTAS): NTAS-18 Mooring Turnaround Cruise Report Cruise On Board RV Ronald H. Brown January 6 –26, 2020 Bridgetown, Barbados – Bridgetown, Barbados

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 are used to investigate air–sea interaction processes related to climate variability. The NTAS Ocean Reference Station (ORS NTAS) is supported by the National Oceanic and Atmospheric Administration’s (NOAA) Global Ocean Monitoring and Observing (GOMO) Program (formerly Ocean Observing and Monitoring Division). This report documents recovery of the NTAS-17 mooring and deployment of the NTAS-18 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 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. The mooring turnaround was done by the Upper Ocean Processes Group of the Woods Hole Oceanographic Institution (WHOI), onboard R/V Ron Brown, Cruise RB-20-01. The cruise took place between January 6 and 26 2020. The NTAS-18 mooring was deployed on January 10, and the NTAS-17 mooring was recovered on January 15. Inter-comparison between ship and buoys were performed on this cruise. This report describes these operations, as well as other work done on the cruise and some of the pre-cruise buoy preparations. Other operations during RB-20-01 consisted in the acoustic communications with the Meridional Overturning Variability Experiment (MOVE) subsurface mooring array MOVE 1-13 and acoustic downloads of data from Pressure Inverted Echo Sounders (PIES) was also conducted at MOVE 1. MOVE is designed to monitor the integrated deep meridional flow in the tropical North Atlantic. Two ARGO floats were also deployed on behalf of the WHOI ARGO group. During the cruise, atmospheric measurements of aerosols, as well as radar, Lidar, radiosondes were made as part of the ATOMIC campaign. 3