M/S Silja Serenade (Helsinki-Stockholm) pCO2 underway measurements in 2020-02


Quality control:Measurements during calibration, cleaning, maintenance and low discharge have been removed.-----Flag system:A flag system is applied to the data. Good data that passes the flag control, gets the flag of 11111111. If the raw CO2 partial pressure (not calibration corrected) is out of boundaries (20-1200 ppm), the first digit changes to 9, i.e. if this is only abnormality, the flag would be 9111111. All flags and their boundary limits are listed in the table below.--Flag => Parameter => Lower boundary to Upper boundary91111111 => CO2_ppm_wet => 20 ppm to 2000 ppm19111111 => T equ => -1 °C to 30 °C11911111 => T tech => -1 °C to 30 °C11191111 => Salinity => 5 to 811119111 => Pressure => 0.9 to 1.111111911 => coeff_A/coeff_B/coeff_C => -50/0.9/-0.0001 to 100/1.3/0.000111111191 => SHEQ_flow_LPM/LICOR_flow => 1.0/50 to N/A/N/A11111119 => Visually inspected bad data-----Calculations:The CO2 molar fraction observed by the LI-840A is denoted as wet CO2 molar fraction (CO2_ppm_wet).--The molar fraction with respect to dry air is calculated as,CO2_ppm_dry = CO2_ppm_wet / (1 - H2O_ppt/1000),where H2O_ppt is the H2O molar fraction measured by the LI-840A.--For each calibration sequence every 4 hour, a 2nd order polynomial function is fitted to the observed and real molar fractions:CO2_ppm_dry_cal_cor = coeff_A + coeff_B * CO2_ppm_dry + coeff_C * (CO2_ppm_dry)^2Polynomial coefficients (coeff_A, coeff_B and coeff_C) are interpolated between the calibrations.--CO2 partial pressure in dry air is calculated as,pCO2_uatm_dry = CO2_ppm_dry_cal_cor * P_eq_atm--The CO2 partial pressure in wet air (Dickson and Goyet, 1994),pCO2_uatm = pCO2_uatm_dry * (1 - Pws_eq_atm)where saturation water vapor pressure, Pws_eq_atm, is calculated from equilibratortemperature, T_eq_degC (Wagner and PruB, 2002, Eq. 2.5).--Temperature corrected CO2 partial pressure is given for the inlet,pCO2_uatm_temp_corr = pCO2_uatm * exp [ A* (T_in_degC - T_eq_degC)]where A = 0.0423 (Takahashi et al., 1993).

DOI https://doi.pangaea.de/10.1594/PANGAEA.928023
Related Identifier https://doi.pangaea.de/10.1594/PANGAEA.928025
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.928023
Creator Laakso, Lauri; Kielosto, Sami; Honkanen, Martti
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2021
Funding Reference Forschungszentrum Jülich GmbH
Rights Data access is restricted (moratorium, sensitive data, license constraints)
OpenAccess false
Language English
Resource Type Dataset
Format text/tab-separated-values
Size 719862 data points
Discipline Earth System Research
Spatial Coverage (18.800W, 59.471S, 24.900E, 59.999N)
Temporal Coverage Begin 2020-02-01T18:51:00Z
Temporal Coverage End 2020-02-29T23:59:30Z