MIRAI MR05-05 Leg2 Partial Pressure of CO2 (pCO2)

Last Modified: 2012-11-25
: MR05-05 Leg2
: Processed (PI)
: CO2, Air temperature, Atmospheric pressure, Wind direction, Wind speed, Sea surface temperature, Sea surface salinity
:
OCEANS > OCEAN CHEMISTRY > CARBON DIOXIDE

For Using Data

Akihiko Murata (JAMSTEC)
See Terms and Conditions about constrain of use.
See Terms and Conditions about data citation.
Instrument:
pCO2 measurement system ( - MR10-06)

      Investigator: Dr. Akihiko Murata
      Organization: Research Institute for Global Change (RIGC)/Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
      Address: 2-15, Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan

Vessel:
Vessel Name: Mirai
Vessel ID: JNSR
Country: Japan
Vessel Owner: JAMSTEC

Equilibrator Design:
Equilibrator type: Shower-head type equilibrator
Equilibrator volume (L): 1.2
Water_Flow_Rate (L/min): 5-8
Headspace_Gas_Flow_Rate (L/min): 0.6-0.8
Vented: During equilibrium, closed circulation of air. When measured by NDIR, vented to ambient air.

Measurement Method:
   Continuous underway measurements of atmospheric and surface seawater pCO2 were made with the CO2 measuring system (Nippon ANS, Ltd) installed in the R/V Mirai of JAMSTEC. The system comprises of a non-dispersive infrared gas analyzer (NDIR; BINOSR model 4.1, Fisher-Rosemount) or the variations, an air-circulation module and a showerhead-type equilibrator. To measure concentrations (mole fraction) of CO2 in dry air (xCO2a), air sampled from the bow of the ship (approx. 30 m above the sea level) was introduced into the NDIR through a dehydrating route with an electric dehumidifier (kept at ~ 2 °C), a Perma Pure dryer (GL Sciences Inc.), and a chemical desiccant (Mg(ClO4)2). The flow rate of the air was 500 ml min-1. To measure surface seawater concentrations of CO2 in dry air (xCO2s), the air equilibrated with seawater within the equilibrator was introduced into the NDIR through the same flow route as the dehydrated air used in measuring xCO2a. The flow rate of the equilibrated air was 600 - 800 ml min-1. The seawater was taken by a pump from the intake placed at the approx. 4.5 m below the sea surface. The flow rate of seawater in the equilibrator was 500 - 800 ml min-1.
   The CO2 measuring system was set to repeat the measurement cycle such as 4 kinds of CO2 standard gases (Table 1), xCO2a (twice), xCO2s (7 times). This measuring system was run automatically throughout cruises by a PC control. Effects of water temperature increased between the inlet of surface seawater and the equilibrator on xCO2s were adjusted based on Gordon and Jones (1973), although the temperature increases were slight, being ~ 0.5 °C at maximum.

Gordon, L. I. and L. B. Jones (1973), The effect of temperature on carbon dioxide partial pressure in seawater. Mar. Chem., 1, 317 - 322.

Manufacturer of Calibration Gas:
   Concentrations of CO2 of the standard gases are listed in Table 1, which were calibrated by the JAMSTEC primary standard gases after 2000 (MR00-K01 and later). Before that time, the standard gases were calibrated against the scale of the Meteorological Research Institute, Tsukuba, Japan, and fitted to the 1985 World Meteorological Organization scale by using the equation of Inoue et al. (1995). The CO2 concentrations of the primary standard gases were calibrated by C. D. Keeling of the Scripps Institution of Oceanography, La Jolla, CA, USA. The values are 230.33 ppm (Cyl. No. 11325), 259.74 (11326), 279.67 (11327), 308.93 (11328), 328.25 (11329), 348.79 (11330), 369.55 (11331), 389.54 (11333), 411.60 (11334), 440.94 (11335), 460.42 (11336), and 478.54 (11337).
   Since differences of concentrations of the standard gases between before and after the cruise were all allowable (< 0.1 ppmv), the averaged concentrations (Table 1) were adopted for the subsequent calculations.

Table 1. Concentrations of standard gases used in individual cruises.

Cruise #STD1STD2STD3STD4Remark
MR98-06----No records left
MR98-K01270.28330.95360.48410.85
MR99-K02270.28330.95360.48410.85
MR99-K04270.26330.98360.43410.85
MR99-K05247.74304.98333.32382.57
MR00-K01329.71359.17409.39439.94
MR00-K03269.60329.71359.17439.94
269.60329.71359.17409.39
MR00-K06246.95305.13333.44382.74
305.13333.44382.74409.40
MR01-K02269.60329.74359.22409.39
MR01-K03269.60329.74359.22409.39
MR01-K04 Leg1298.56321.17370.75439.95
MR01-K04 Leg2298.56321.17370.75439.95
MR01-K05 Leg1-2247.99298.56321.17370.75
MR01-K05 Leg3-4247.99298.56321.17370.75
MR02-K03269.20329.52359.11408.76
MR02-K05 Leg1246.69297.83320.05391.66
MR03-K01270.16340.21371.39389.97
MR03-K02270.08328.87359.10409.23
MR03-K04 Leg1270.08328.87359.10409.23
MR03-K04 Leg2270.08328.87359.10409.23
MR03-K04 Leg4270.08328.87359.10409.23
MR03-K04 Leg5268.84330.16369.37414.39
MR04-04268.85328.87369.39414.43
MR04-05268.84330.16369.37414.39
MR05-02262.94320.42381.04420.76
MR05-05 Leg1262.94320.42381.04420.76
MR05-05 Leg2262.94320.42381.04420.76
MR05-05 Leg3262.94320.42381.04420.76
MR06-04 Leg1289.76349.00393.75439.72
MR06-04 Leg2289.76349.00393.75439.72
MR07-04289.77349.02393.77439.75
MR07-05289.77349.02393.77439.75
MR07-06 Leg1270.02330.40369.28419.68
MR07-06 Leg2270.02330.40369.28419.68
MR09-01 Leg1270.22330.43360.04420.32
MR09-01 Leg2270.22330.43360.04420.32

Inoue, H. Y., H. Matsueda, M. Ishii, K. Fushimi, M. Hirota, I. Asanuma, and Y. Takasugi (1995), Long-term trend of the partial pressure of carbon dioxide (pCO2) in surface waters of the western North Pacific 1984 - 1993. Tellus 47B, 391 - 413.

CO2 Sensors:
Manufacturer: Rosemount Analytical
Model: BINOS 4.1
Resolution: -
Uncertainty: -

: MR05-05 Leg2
: Processed (PI)
: CO2, Air temperature, Atmospheric pressure, Wind direction, Wind speed, Sea surface temperature, Sea surface salinity
:
OCEANS > OCEAN CHEMISTRY > CARBON DIOXIDE

Observation Map

Data List

  File names
MR05-05_leg2_pco2.zip
: MR05-05 Leg2
: Processed (PI)

pCO2 FORMAT_J

Air-xCO2
  1. The file is in fixed length, comma separated text file (csv) format.
  2. The "missing value" is defined as -999.
Column NO. Column Heading Comments
1 Date Year/Month/Day (YYYY/MM/DD) in UTC
2 Time Hour:Minute:Second (HH:MM:SS) in UTC
3 Latitude Latitude (degree) ; Positive in north
4 Longitude Longitude (degree) ; degree in eastward (0 - 360)
5 Atm_Tmp Air temperature (degree C)
6 Atm_Prs Barometric pressure (hPa)
7 Wind_Dir Wind direction (degree)
8 Wind_Spd Wind speed (m/s)
9 SST Sea surface temperature (degree C)
10 SSS Sea surface salinity (PSU)
11 xCO2_Air CO2 mixing ratio (ppmv) in the 'dry air' taken from the fore-mast of the ship.
Sea-xCO2
  1. The file is in fixed length, comma separated text file (csv) format.
  2. The "missing value" is defined as -999.
Column NO. Column Heading Comments
1 Date Year/Month/Day (YYYY/MM/DD) in UTC
2 Time Hour:Minute:Second (HH:MM:SS) in UTC
3 Latitude Latitude (degree) ; Positive in north
4 Longitude Longitude (degree) ; degree in eastward (0 - 360)
5 Eq_Tmp Temperature in equilibrator (degree C)
6 Eq_Prs Pressure in equilibrator (mmHg)
7 SST Sea surface temperature (degree C)
8 Atm_Prs Air pressure (hPa)
9 SSS Sea surface salinity (PSU)
10 xCO2_Sea CO2 mixing ratio (ppmv) in the 'dry air' equilibrated with surface.

Related Information

Update History

2012-11-25
An observation data was registerd.