R/V SEWARD JOHNSON departed Port of Spain, Trinidad for the second leg of cruise SJ9703 on June 23, 1997 and arrived in Fortaleza, Brazil on 26 July, 1997. This was the second leg of the SEWARD JOHNSON for this cruise number (called here ACCE2). The first leg (WIMP14) left from Fort Peirce, FL on June 9, 1997 and arrived into Port of Spain on June 21. Details of this cruise are included in a separate report. The final leg of cruise SJ9703 (hereinafter, ACCE3) departed Fortaleza on 28 July and arrived in Cape Town, South Africa on 17 August. This cruise was supported by the National Oceanic and Atmospheric Administation Office of Atmospheric and Oceanic Research (OAR). There were almost no problems with the basic sampling program and the weather was excellent for the most part throughout ACCE2 and ACCE3. The ship had considerable difficulty with its traction winch and one engine during ACCE2. Sampling was broken off for seven days to return to Barbados for engine repairs. However, the crew was excellent and Harbor Branch was able to accomodate the scientific goals of the cruise.
Stations were numbered consecutively from the beginning of the R/V SEWARD JOHNSON SJ97-03 work from Ft. Pierce to Trinidad in WIMP14 with sampling along the Windward Islands (Wilson, chief scientist). The first station on ACCE2 was numbered 60 and was a test station. Considerable problems were noted with the 11 of the 24 Niskin bottles leaking. After a complete overhall of the rosette, another test station, number 61 revealed no problems. The first complete station was 62. The last station was 115. The first station on ACCE3 was 116 and the last 146.
The cruise plan for ACCE2 called for sampling northeastward from the 100m isobath off French Guiana along an historical STACS section (last sampled in 1989). The track was then to proceed eastward along 6oN to the coast of Africa into Liberia, then down to the equator near 10W and back west towards Brazil. ACCE3 was to steam east along 6oS to the coast of Africa. Because of the lack of clearances to work in Angolan waters a slight dog leg was introduced on the eastern end of the line to sample in Congo waters (for which clearances were obtained). The goals of the sampling were to deploy PALACE floats along the three zonal sections and to obtain upper ocean sections to estimate the flow of the warm water sphere flowing into the North Atlantic and changes within the equatorial zone. Particular attention was to be paid to calibration of the PALACE floats.
Most stations were to at least 1500 meters depth (1600m and 2000m during ACCE3, with the shallower sampling instituted to save time) and included a rosette/CTD cast equiped with a lowered acoustic doppler profiler (LADCP). Basic station spacing was 60 nm during ACCE2. Station spacing at the French Guiana and Liberian coasts was less than 30 nm and dictated by topography. Station spacing during ACCE3 ranged from 90 to 150 nm because of time constraints.
Sampling was done with a 24-place General Oceanics pylon on a rosette frame with 10-liter bottles and a CTD (AOML CTD 1), LADCP and pinger. The CTD data stream consisted of elapsed time, pressure, two temperature sensors, two conductivity sensors, and two oxygen sensors. Water samples were collected for analyses of salt, and oxygen. On all stations, an RDI lowered acoustic doppler profilers (LADCP) was mounted inside the rosette frame. A narrow band unit operating at 300kHz LADCP was used. Underway shipboard ADCP data were logged (Wilson). No substantial problems were encountered.