Surface underway seawater and marine boundary layer observations of partial pressure of carbon dioxide (pCO2), water temperature, salinity and other parameters made during the M/V Seaspan Royal cruises in the coastal waters of British Columbia, Canada from 2022-07-01 to 2022-12-20

This dataset consists of surface underway measurements collected from the M/V Seaspan Royal as it transited the coastal waters of British Columbia, Canada from 2022-07-01 to 2022-12-20. Seawater was drawn from a depth of 2.5 m to a Sunburst SuperCO2 system and ancillary sensors from Sea-Bird Scientific. Measurements of temperature, salinity, dissolved oxygen content, and CO2 partial pressure were made every 2 seconds on seawater flowing through the system and instruments, and these data were logged by the SuperCO2 system. Seawater was delivered from the intake to analytical equipment using an AMT 1/2 HP pump (4295-98). Temperature and salinity data were collected using a Fluke thermometer (model 1523) with thermistor probe (model 5610) in the equilibrator, a Sea-Bird SBE 45 MicroTSG Thermosalinograph, and a SBE 38 Digital Oceanographic Thermometer at the seawater intake. Dissolved oxygen content was measured using a SBE63 oxygen optode. Raw oxygen measurements (with salinity reference = 0) were corrected for salt content following the approach provided with the SBE63 Manual revision 010. CO2 measurements were made with a LI-COR LI850 non-dispersive infrared detector housed with the SuperCO2 system. Standardization of the CO2 measurements was achieved through the measurement of four gas standards (Linde; 98.83 ppm, 386.30 ppm, 469.69 ppm, and 1248.45 ppm) that had undergone re-calibration using a zero (N2) and span gas (ESRL; 1567.44 ppm) bracketing the gas standard concentrations. A standardization sequence (measurement of each gas standard sequentially for a period of 90 seconds) was conducted every 4 or 12 hours (over different periods of the data record) and included a 90-second measurement period of atmospheric CO2 partial pressure on air drawn to the system from an intake on the aft deck. The final 20 seconds of atmospheric measurements were retained in the final dataset. Position and weather information (from an Airmax 120WX Weatherstation instrument positioned above the bridge) were logged separately from the SuperCO2 system data, and then merged with the SuperCO2 system data by time-matching the position and weather data to the SuperCO2 system data. This project was supported by the Tula Foundation and Seaspan.