The CTD data acquisition, processing and control system consisted of the SEWARD JOHNSON's Seabird data acquisition PC and Deck unit, AOML's Seabird 9/11 (CTD #1), broad band LADCP, Seabird pylon and three acquisition and processing PCs. The PCs are equipped with Syquest disks, floppy drives and hard disks for data backups. Two other computer systems, a Digital Vaxstation and a Digital Unix Decstation 5000/200 both with 9 gig disks were networked to the data acquisition system, as well as to the rest of the networked computers aboard the SEWARD JOHNSON. These systems were available for real-time CTD data display as well as providing hydrographic data management and backup. The SEWARD JOHNSON's Lexmark 600 dpi printer and AOML's HP Laserjet 4p and color HP DeskJet 820 Cse provided hardcopy.
The CTD data acquisition, processing and control system was prepared by the console watch a few minutes before a deployment. A console operations log was maintained for each deployment, containing a record of every attempt to trip a bottle as well as any pertinent comments. The CTD and plyon power supplies were continually left on after station 71 to eliminate the transient pressure fluctuations inherent in the Seabird sensor during the first ten minutes of startup. After completion of the operations log, verifying power to the Deckunit and stable readings recorded by the Seabird display, the operator would inform the deck watch to proceed.
Once the deck watch had deployed the rosette and informed the console operator that the rosette was at the surface (a formality, since the data acquisition system had already made it known), the console operator would wait for a confirmation that the Seabird pump units have turned on (typically one minute or less) and provided the winch operator with a target depth (wire-out) and lowering rate (normally 60 meters/minute for this package). The package would then begin its descent.
The console operator would examine the processed CTD data during descent via plot windows on the display. Additionally, the operator would decide where to trip bottles on the up-cast, noting this on the console log. The PDR was monitored to insure the bottom depth was known at all times.
When necessary, the watch leader would assist the console operator when the package was 400 meters above the bottom, and verify the range to the bottom using the distance between the bottom reflection and pinger signal displayed on the PDR. The SEWARD JOHNSON on-screen CHIRP II displays allowed the watch leader to monitor the depth and safely approach to within 10 meters of the bottom.
Bottles would be tripped and the console operator would wait for a trip confirmation signal sent to the SBE 11 deck unit. All tripping attempts were noted on the console log. The console operator would then direct the winch operator to the next bottle stop. The console operator was also responsible for generating the sample log for the cast. After the last bottle was tripped, the console operator would direct the deck watch to bring the rosette on deck. Once on deck, the console operator would terminate the data acquisition and leave turned-on the CTD, pylon and aquisition computer. The acquired data was them backed up to the CTD Processing computer and a Syquest disk.