The Northwest Tropical Atlantic Station (NTAS): NTAS-2 Mooring Turnaround Cruise Report

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 deg. N, 51 deg. 00W by successive mooring turnarounds. These observations will be used to investigate air-sea interaction processes related to climate variability. Deployment of the first NTAS mooring (NTAS-1) at 14050 N, 51000 W on 30 March 2001 was documented in a previous report (Plueddemann et al., 2001). This report documents recovery of the NTAS-1 mooring and deployment of the NTAS-2 mooring at the same site. Both moorings used 3-meter discus 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%ea fluxes of heat, moisture and momentum. The upper 120 m of the NTAS-1 mooring line, and the upper 150 m of the NTAS-2 mooring line, were outfitted with oceanographic sensors for the measurement of temperature and velocity. The mooring turnaround was done on the NOAA Ship Ronald H. Brown, Cruise RB-02-02, by the Upper Ocean Processes Group of the Woods Hole Oceanographic Institution. The cruise took place between 2 and 8 March 2002. A SeaBeam bathymetry survey of the site was done first, followed by deployment of the NTAS-2 mooring on 4 March at approximately 14 deg. 44.3' N, 50 deg. 56.8 W in 5043 m of water. A 24-hour intercomparison period followed, after which the NTAS-1 mooring was recovered. This report describes these operations, as well as some of the pre-cruise buoy preparations. --Original contains color plates: All DTIC reproductions will be in black and white.