Citation:

PANGAEA.928025 (dataset in review)

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Project(s):

Integrated carbon and trace gas monitoring for the Baltic Sea (BONUS_INTEGRAL)

Funding:

Bundesministerium für Bildung und Forschung, Bonn (BMBF), grant/award no. 03F0773A : Integrated carbon and trace gas monitoring for the Baltic Sea

Coverage:

Median Latitude: 59.749615 * Median Longitude: 19.821305 * South-bound Latitude: 59.593470 * West-bound Longitude: 18.803380 * North-bound Latitude: 59.995890 * East-bound Longitude: 21.026990

Date/Time Start: 2018-04-12T17:51:00 * Date/Time End: 2018-04-12T23:37:00

Event(s):

Serenade_2018-04 * Latitude Start: 60.166000 * Longitude Start: 24.933000 * Latitude End: 59.325000 * Longitude End: 18.050000 * Date/Time Start: 2018-04-01T00:00:00 * Date/Time End: 2018-04-30T00:00:00 * Campaign: * Basis: * Method/Device: Underway cruise track measurements (CT) * Comment: Helsinki-Mariehamm-Stockholm

Comment:

Quality control:

Measurements during calibration, cleaning, maintenance and low discharge have been removed.

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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 boundary

91111111 => CO2_ppm_wet => 20 ppm to 2000 ppm

19111111 => T equ => -1 °C to 30 °C

11911111 => T tech => -1 °C to 30 °C

11191111 => Salinity => 5 to 8

11119111 => Pressure => 0.9 to 1.1

11111911 => coeff_A/coeff_B/coeff_C => -50/0.9/-0.0001 to 100/1.3/0.0001

11111191 => SHEQ_flow_LPM/LICOR_flow => 1.0/50 to N/A/N/A

11111119 => Visually inspected bad data

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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)^2

Polynomial 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 equilibrator

temperature, 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).

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Method/Device	Comment
1	DATE/TIME	Date/Time		Laakso, Lauri		Geocode – UTC
2	LATITUDE	Latitude		Laakso, Lauri		Geocode
3	LONGITUDE	Longitude		Laakso, Lauri		Geocode
4	xCO2 (water) at sea surface temperature (wet air)	xCO2water_SST_wet	µmol/mol	Laakso, Lauri		read from LI-840A
5	xCO2 (water) at sea surface temperature (dry air)	xCO2water_SST_dry	µmol/mol	Laakso, Lauri
6	Temperature at equilibration	Tequ	°C	Laakso, Lauri	Digital oceanographic thermometer, Sea-Bird, SBE 38
7	Temperature, technical	T tech	°C	Laakso, Lauri		inlet temperature
8	Temperature, difference	delta T	°C	Laakso, Lauri
9	Water vapour mixing ratio	H2O mix ratio	mmol/mol	Laakso, Lauri
10	Pressure	Press	atm	Laakso, Lauri		saturation H2O pressure inside the chamber (calculated)
11	Pressure	Press	atm	Laakso, Lauri		Total pressure inside the equilibrium chamber
12	Quality flag	QF		Laakso, Lauri		for CO2, see dataset comment for details
13	Salinity	Sal		Laakso, Lauri	Thermosalinograph, Sea-Bird, SBE 45	PSU
14	Flow rate	Flow rate	l/min	Laakso, Lauri		SHEQ, water flow rate to the showerhead equilibrators
15	Flow rate	Flow rate	l/min	Laakso, Lauri		LICOR, air flow rate to the gas analyser ml/min recalc!
16	Flow rate	Flow rate	l/min	Laakso, Lauri		total water flow rate

License:

Creative Commons Attribution 4.0 International (CC-BY-4.0)

Size:

6187 data points

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