Brief Cruise Summary
According to the WOCE Implementation Plan, the cruise line for WOCE Section A5 was to be located at 24° N. Since two oceanographic sections had previously been made (1957 and 1981) around 24.5° N (Roemmich and Wunsch 1985), the WOCE International Program Office (IPO) agreed to a request by the chief scientist to move WOCE Section A5 to this latitude for data comparison purposes.
The R/V Hespérides departed from Cadiz, Spain, on July 14, 1992. The cruise track and station locations are shown in Fig. 1. During the cruise, 118 CTD/rosette stations were occupied. Six stations were made to test the CTD and rosette. Four test stations were occupied before the ship arrived at Santa Cruz de Tenerife, Canary Islands, on July 17. The ship left Tenerife on July 18 and occupied two more test stations before arriving at Las Palmas de Gran Canaria. (The data from the six test stations are not included in this NDP.) The ship departed from Las Palmas in the early hours of July 20 and arrived at the first station of WOCE Section A5 the same day. After 101 stations were made, the ship arrived at the Bahamas on August 14 and WOCE Section A5 was completed. During the next day, 11 additional hydrographic stations were collected in the Straits of Florida and the cruise was concluded. For navigation and placement of stations, a global positioning system (GPS) was used.
Because of ship time constraints, station spacing was determined as follows: The first six stations of WOCE Section A5 were located at the 50-, 100-, 150-, 1500-, 2000-, and 2500-m isobaths and were about 18 nautical miles (nm) apart; from there to the 4000-m depth (Station 12), the distance between stations was about 23 nm. From Station 12 to the eastern limits of the Mid-Atlantic Ridge, the stations were separated by 36 nm. Across the Ridge, the separation was 32 nm. From the western limits of the Mid-Atlantic Ridge to the 5000-m isobath near the Bahamas, stations were again separated by 36 nm. Stations close to the Bahamas were separated by less than 30 nm. The stations across the Straits of Florida were occupied every 5 nm.
Near the Bahamas, the expedition deviated slightly from the planned cruise track in order to cross the continental slope perpendicularly to the direction of the isobaths and to obtain a clear crossing of the Deep Western Boundary Current.
The ADCP and a thermosalinograph recorded continuously during the entire cruise. Wind information was recorded every hour. Basic sampling equipment included three CTDs and a 24-bottle General Oceanics (GO) rosette system equipped with 10- or 12-L water sampling bottles.
The TCO2 concentration was determined in 660 samples from 33 of the 112 CTD stations occupied during the cruise (Fig. 2)
At the end of the cruise the ship was checked for tritium and 14C contamination by the Tritium Laboratory of the University of Miami.
