M/V Atlantic Companion cruise: COM_11 This cruise were part of the European CARBOOCEAN project. Initial submission: 2006 Most recent update: 12. Dec 2010 Date of cruise (dd/mm/yyyy): 17.07. - 21.07.2006 Geographic coverage: 52N, 7W - 44N, 63W Ports of call: Liverpool, UK - Halifax, Canada Vessel name: M/V Atlantic Companion Vessel ID: SKPE Country: Sweden Owner: Atlantic Container Lines PI: Tobias Steinhoff Leibniz Institute of Marine Sciences (IFM-GEOMAR) Duesternbrooker Weg 20 24105 Kiel Germany tsteinhoff@ifm-geomar.de Citation: Steinhoff, T., Wallace, D.W.R. and Koertzinger, A. (2006). Preliminary underway fCO2 measurements in the North Atlantic Ocean on M/V Atlantic Companion in July 2006. Reported variables: (1) Cruise ID (2-4) Year|Month|Day date (5-7) Hour|Minute|Second time (UTC) (8) Day of year decimal year day (9) Longitude [deg E] Longitude in decimal degrees E (10) Latitude [deg N] Latitude in decimal degrees N (11) SST [deg C] Sea surface temperature in deg C (12) SSS Sea surface salinity (13) Atm. Pressure [mbar] Atmospheric pressure in mbar (14) Equi Temp [deg C] Water temperature inside the equilibrator in deg C (15) Equi Press [mbar] Pressureinside the equilibrator in mbar (16) xCO2 (equi temp, dry) [ppm] mole fraction of CO2 in the equilibrator headspace (dry) at equilibrator temperature in ppm (17) pCO2 (SST, 100hum) [uatm] partial pressure of CO2 in seawater at SST and 100% humidity in uatm (18) fCO2 (SST, 100hum) [uatm] fugacity of CO2 in seawater at SST and 100% humidity in uatm (19) Atm. xCO2 (dry) [ppm] mole fraction of CO2 of atmospheric air in ppm (20) Atm xCO2 (dry, running mean) [ppm] same as 18 but with a running mean to interpolate between measurements. Instrument information: - SST (+- 0.05 deg C): SST was measured with a factory calibrated thermosalinograph from Seabird (SBE45) with an external SBE38 which was installed approximately 30 cm after the seawater intake. -SSS (+- 0.5 PSU): Same as SST. The SSS readings were too low, therefore SSS from the pCO2 climatology of Takahashi et al. (2009) was used. -Atmospheric press. (+- 0.1 mbar): The atm. Pressure was measured on the top of the vessel, using a static pressure head to minimize wind induced errors. -Equilibrator temp (0.05 C): The temperature probe inside the equilibrator was compared to the SBE38 every 3 months. -Equilibrator press (+- 0.1 mbar): Absolute measurements. -pCO2/fCO2 (+- 2uatm): IR sensor: Licor 6252, calibrated with 2 standard gases. Standard gases: Deuste Steininger (350.1, 450.2 ppm), calibrated against NOAA/CMDL standard gases. Resulting uncertainty: +- 0.5 ppm. Water flow rate: 2-3 L min-1 Gas flow rate: 100 mL min-1 A so-called Neill system was used for pCO2 measurements. The system is described in detail in Pierrot (2009) and the whole setup is described in Steinhoff (2010). Surface water is pumped continuously (by a torque flow pump) from the intake to the equilibrator. The equilibrator contains a water spray head, and as the water flows through it the dissolved CO2 equilibrates with the headspace. The headspace is dried and xCO2 is determined by an infrared sensor. Calculations were performed following Pierrot (2009) and are described in detail in Steinhoff (2010). Pierrot, D., Neill, C., Sullivan, K., Castle, R., Wanninkhof, R., Luger, H., Johannessen, T., Olsen, A., Feely, R. A., and Cosca, C. E. (2009). Recommendations for autonomous underway pCO2 measuring systems and data reduction routines. Deep-Sea Res. II , 56, 512_522. Steinhoff, T. (2010). Carbon and nutrient fluxes in the North Atlantic Ocean. Dissertation. http://eldiss.uni-kiel.de/macau/receive/dissertation_diss_00005704 Takahashi, T, S.C. Sutherland, R. Wanninkhof, C. Sweeney, R.A. Feely, D.W. Chipman, B. Hales, G. Friederich, F. Chavez, C. Sabine, A. Watson, D.C.E. Bakker, U. Schuster, N. Metzl, H. Yoshikawa-Inoue, M. Ishii, T. Midorikawa, Y. Nojiri, A. Koertzinger, T. Steinhoff, M. Hoppema, J. Olafsson, T.S. Arnarson, B. Tilbrook, T. Johannessen, A. Olsen, R. Bellerby, C.S. Wong, B. Delille, N.R. Bates und H.J.W. de Baar (2009). Climatological mean and decadal change in surface ocean pCO2, and net sea-air CO2 flux over the global oceans. Deep-Sea Res. II, 56, 554-577.