CalCOFI 1104SH CTD Data Processing Notes

  • Cast 031-033 (really leg 3's cast 001-003) CTD Deck Unit v2 was used then switched because of an overflow error after 5mins of data collection. Cast 034 (leg 3's cast 4) and all subsequent casts were done on our backup deck unit v1 which does not auto-offset the secondary conductivity sensor by 0.073. So AlignCTD was applied to all secondary conductivity sensor data from casts 034-114. In retrospect, it was probably due to the remote depth out rewiring by Shimada ET Garry. He wired the readout box to the winch shack and miswiring may have caused the problem. The v2 deck unit will be run ashore to assess the problem.
  • Casts 031-036 primary conductivity sensor values were bad; sensor coefficients were triple-checked and looked correct so the sensor was changed on cast 037. The conductivity/salinity sensor response looks good but offset. Perhaps a post-cruise calibration could be applied. Use secondary conductivity and sensor data - they look fine.
  • Transmissometer M & B were calculated post-cruise so use 031-036.con & 037-114.con files to process data if beam attenuation & % light transmission transmissometer data are desired.
  • Some casts early in the cruise were renumbered to match NMFS order occupied which counts trawls between sta as separate stas: 40 > 42; 41 > 43; 42 > 45; 43 > 46; 44 > 47; 79 > 80

Initial processing of CTD data produced spikey data profiles particularly on the upcast for stas: 48, 51, 52,56,57,58,61,62,64,70,71,73,86,99,107,108, & 109. Oddly, reprocessing all casts because of the PAR sensor omission the first run resulted in non-spikey data. Have no idea why re-running the data improved the data quality but wanted to make a note as to this odd occurance for future reference.

CalCOFI 1104SH General Shimada Data Collection Notes

  • The Shimada was unable to deploy the CTD to 3500m because of wire-shortage.
  • The CTD was typically lowered at 35m/min to 100m CTD depth then increased to 60m/min. Some casts were unable to go faster than 35m/min unless the winch stopped then restarted down.
  • Our deck unit and blade pc was used in the forward dry lab, attaching to CTD junction box 2.
  • No underway data were collected directly by MetCap or UWay program. The ship GPS was attached to blade2 which ran the Eventlog with GPS actively (gps serving) for shipwide eventlog use. Unfortunately, blade2 was unable to run both the Eventlog & the Weather program. The weather program was jerky and unusable on the iPad tablet. Recommend a blade2 upgrade.
  • Taglines were used on both deployment (high & low) and recover (both low) to assist in controlling and positioning the rosette especially when full. Ship roll is minimal but upper deck clearance is very tight.
  • Surface PAR data was not collected. Remote Depth Readout box was attempted but scrubbed.
  • Survey techs radioed the desired CTD depth and counted down the meters upon approach. This worked ok except when the wire angle was high and CTD settled.