Surface underway measurements of partial pressure of carbon dioxide (pCO2) in water and atmosphere, sea surface temperature, sea surface salinity and barometric pressure obtained during the M/V Tavastland cruises in the Baltic Sea in 2020 (NCEI Accession 0225416)

This dataset includes surface underway measurements of partial pressure of carbon dioxide (pCO2) in water and atmosphere, sea surface temperature, sea surface salinity and barometric pressure collected during the M/V Tavastland cruises in the Baltic Sea in from 2020-01-07 to 2020-06-15. A General Oceanics (GO) pCO2 system (model 8050) was used for pCO2 measurements. The system is described in detail in Pierrot (2009). Surface water is pumped continuously 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). The water is drawn directly from the sea chest at 6m depth. A temperature sensor (SBE38) is installed close to the intake. The water is pumped through 5 m of a piping connecting to the GO system. The equilibrator pressure is measured using a differential pressure sensor (inside/outside equilibrator) and an absolute pressure sensor next to the equilibrator. The air inlet is located 30 m above sea level next to the ship's funnel and the air line is constantly flushed with atmospheric air.