D340A Discrete Salinity Sampling Document
Originator's Protocol for Data Acquisition and Analysis
Discrete salinity samples were collected on the majority of CTD casts performed during the cruise. At least three samples were typically obtained per cast - one from each of the CTD Niskin bottles selected for analysis. Replicate samples from the same Niskin bottle were occasionally taken to monitor analytical quality. In addition, discrete samples were also drawn from the ship's non-toxic underway supply at approximately four hour intervals.
Sample collection was carried out carefully. Clean glass sample bottles were used. Each of these was rinsed three times in the sample stream prior to being filled to below the neck of the bottle. After wiping residual droplets from the neck with clean tissue, a clean plastic stopper was placed in the top and the bottle cap fitted. Samples were taken to the constant temperature laboratory to stabilise prior to analysis.
The samples were analysed onboard using a Guildline Autosal 8400B (s/n 65764) salinometer in the constant temperature laboratory (keep at 24 °C).
CTD bottle salinities were ultimately used by the data originator to calibrate both CTD conductivity sensors. Data were split into two sets to calibrate the CTD sensors. The first dataset contained data collected from oceanic waters sampled from Iceland to the Scottish shelf, including the Wyville Thomson Ridge area. The second dataset included coastal data collected on the Scottish shelf.
Discrete underway salinity samples were used to calibrate the thermosalinograph conductivity sensor data stream.
BODC Data Processing Procedures
The salinity data were supplied to BODC in Microsoft Excel format. Salinity values were extracted from this and loaded into BODC's ocean database under the ORACLE Relational Database Management System. Replicate data were averaged, when appropriate, prior to loading. Data that were considered unrealistic were flagged suspect.
Content of data series
| Originator's Parameter | Unit | Description | BODC Parameter code | BODC Unit | Comments |
|---|---|---|---|---|---|
| CTD bottle and discrete underway salinity | - | Practical salinity of the water column | PSALBSTX | - | N/A |
References Cited
Sherwin T. A. et al. , 2009. Cruise D340A Reykjavic to Dunstaffnage via Rockall and the Wyville Thomson Ridge. Internal Report No 264. Scottish Association for Marine Science.
Available - Cruise D430A Internal Report
