CTD Data are available in three main formats: zip-compressed raw cast files (.dat or .hex, .hdr, .con, .mrk, .bl Seasave data files); Seasave-processed .asc and .hdr (asciiout) down and up cast files; and combined data (1m depth binavg'd CTD .asc data merged with bottle data at ~20 depths) in csv-format. The combined-data csvs include columns of 'Seasave-processed-only' 1m data and 'bottle vs CTD regression-corrected' 1m data. CTD Asc Filename Change Tuesday, 30 June 2009 13:00 JRW Since 9308 (August 1993), the CalCOFI group has collected water samples and data using a Seabird CTD 24 bottle rosette. From Aug 1993 to mid 1998, a Seabird 9/11 rosette collected electronic and discrete samples from the standard 66 stations. In May 1998, the Seabird 9/11 CTD was upgraded to a 9/11plus, our current system (2004). Typical sensors: * Dual Temperature SBE 3 (pre 1998) or SBE 3plus & Conductivity SBE 4 * Oxygen - SBE 13 (Beckman) & SBE 43 (since 2003) * Fluorometer o SeaTech Fluorometer - 1993-2000 o Seapoint Fluorometer - since 2000 o Backups - WetLabs; Chelsea; Turner Design SCUFA * Transmissometer (660nm) o SeaTech 25cm Transmissometer or o SeaTech 20cm Transmissometer or o WetLabs 25cm Transmissometer * PAR - Biospherical QSP-200L Scalar Irradiance Remote Sensor * Pylon-Carousel - General Oceanics Pylon; Seabird SBE 32 Carousel (since ‘98) * 24 - 10 liter (productivity-clean; no metals) PVC bottles The dual-pumped CTD system records raw data at 24Hz (24 records/sec). Connected to a ship-board data-acquisition computer through an electronic winch wire, the CTD sensor data are displayed real-time on the computer screen. The CTD-rosette is lowered to the desired terminal depth (usually 515m; 30m/min to 100m then 60m/min to depth; bottom depth & weather-permitting) without stopping. The upcast bottle closure depths are based on the depth of the chlorophyll maximum observed during the downcast. Water samples are taken from the rosette bottles: oxygens first, followed by salinity, nutrient, chlorophyll, and HPLC samples. Oxygen, salinity, nutrient, and chlorophyll samples are analyzed on the ship usually within 24 hours by the CalCOFI scientists, technicians, and volunteers. CTD data are processed using the standard Seabird data processing methods-software. One decibar bin-averaged processed continuous data are then plotted against the discrete salinity, oxygen, and chlorophyll samples. The bottle-CTD salinity average offset is calculated; a CTD vs bottle oxygen 2nd order polynomial regression correction derived; 2nd or 3rd order polynomial fluorometer voltage vs extracted chlorophyll regression derived. These corrections are applied to the averaged continuous data, re-plotted then checked for correctness. CTD asc filenames have typically been 'd or u' YYMMPPP.asc & .hdr (d or u = down or up casts; YY is year; MM month; PPP order occupied or proc #). To standardize the file naming, the .asc & .hdr will be renamed to match the bottle-corrected csvs, YYYYMM_LLLLSSSS_PPPud.*, where YYMM is year month; LLLLSSSS is decimal Line & Sta (minus the '.'); PPP is order occupied (or processing number); u or d for up or down. Last Updated on Tuesday, 30 June 2009 15:03 CTD ASc Format Change Tuesday, 30 June 2009 12:43 JRW Voltage column headers in .asc files will be converted from "V0 V1 V2..." to sensor-specific labels. If V0 is transmissometer then the column header will be changed from "V0" to "TransV". Since the sensors can be mounted on different voltage channels on different cruises (or even the same cruise), this labeling scheme is important for easily distinguishing the sensor voltages. JRW 06/30/2009 Last Updated on Tuesday, 30 June 2009 15:03 CTD ASC Formats Thursday, 02 July 2009 10:32 admininstrator 4sec asc columns - for comparison to bottle data to derive correction coefficients # name 0 = scan: Scan Count # name 1 = timeJ: Julian Days; converted to DD MMM YYYY HH:MM:SS # name 2 = prDM: Pressure, Digiquartz [db] # name 3 = t090C: Temperature [ITS-90, deg C] # name 4 = t190C: Temperature, 2 [ITS-90, deg C] # name 5 = v0: Voltage 0 # name 6 = v1: Voltage 1 # name 7 = v2: Voltage 2 # name 8 = v3: Voltage 3 # name 9 = v4: Voltage 4 # name 10 = v5: Voltage 5 # name 11 = v6: Voltage 6 # name 12 = v7: Voltage 7 # name 13 = flSP: Fluorescence, Seapoint # name 14 = latitude: Latitude [deg] # name 15 = longitude: Longitude [deg] # name 16 = depSM: Depth [salt water, m], lat = 33.2358 # name 17 = potemp090C: Potential Temperature [ITS-90, deg C] # name 18 = potemp190C: Potential Temperature, 2 [ITS-90, deg C] # name 19 = sal00: Salinity [PSU] # name 20 = sal11: Salinity, 2 [PSU] # name 21 = sigma-é00: Density [sigma-theta, Kg/m3] # name 22 = sigma-é11: Density, 2 [sigma-theta, Kg/m3] # name 23 = sbeox0ML/L: Oxygen, SBE 43 [ml/l], WS = 4 # name 24 = sbeox0Mm/Kg: Oxygen, SBE 43 [umol/Kg], WS = 4 # name 25 = sbeox0PS: Oxygen, SBE 43 [% saturation], WS = 4 # name 26 = dm: Dynamic Meters [10 J/Kg] # name 27 = sva: Specific Volume Anomaly [10-8 * m3/Kg] Final asc columns that are combined with corrected values & bottle data # name 0 = scan: Scan Count # name 1 = timeJ: Julian Days; converted to DD MMM YYYY HH:MM:SS # name 2 = prDM: Pressure, Digiquartz [db] # name 3 = t090C: Temperature [ITS-90, deg C] # name 4 = t190C: Temperature, 2 [ITS-90, deg C] # name 5 = v0: Voltage 0; relabeled to sensor voltage such as 'TransV' # name 6 = v1: Voltage 1; relabeled to sensor voltage such as 'FluorV' # name 7 = v2: Voltage 2; relabeled to sensor voltage such as 'AltV' # name 8 = v3: Voltage 3; relabeled to sensor voltage such as 'PARV' # name 9 = v4: Voltage 4; relabeled to sensor voltage such as 'O2V' # name 10 = v5: Voltage 5; relabeled to specific sensor voltage if used # name 11 = v6: Voltage 6; relabeled to sensor voltage such as 'ISUSV' # name 12 = v7: Voltage 7; relabeled to specific sensor voltage if used # name 13 = spar: SPAR/Surface Irradiance # name 14 = bat: Beam Attenuation, Chelsea/Seatech/Wetlab CStar [1/m] # name 15 = xmiss: Beam Transmission, Chelsea/Seatech/Wetlab CStar [%] # name 16 = flSP: Fluorescence, Seapoint # name 17 = latitude: Latitude [deg] # name 18 = longitude: Longitude [deg] # name 19 = depSM: Depth [salt water, m], lat = 34.39 # name 20 = potemp090C: Potential Temperature [ITS-90, deg C] # name 21 = potemp190C: Potential Temperature, 2 [ITS-90, deg C] # name 22 = sal00: Salinity [PSU] # name 23 = sal11: Salinity, 2 [PSU] # name 24 = sigma-é00: Density [sigma-theta, Kg/m3] # name 25 = sigma-é11: Density, 2 [sigma-theta, Kg/m3] # name 26 = sbeox0ML/L: Oxygen, SBE 43 [ml/l], WS = 4 # name 27 = sbeox0Mm/Kg: Oxygen, SBE 43 [umol/Kg], WS = 4 # name 28 = sbeox0PS: Oxygen, SBE 43 [% saturation], WS = 4 # name 29 = dm: Dynamic Meters [10 J/Kg] # name 30 = sva: Specific Volume Anomaly [10-8 * m3/Kg] # name 31 = nbin: number of scans per bin Please note that sensor voltage column order may change from cruise to cruise; sensor type, units, brand or other specifics may vary; some sensor voltage columns may be missing when sensors are not installed.