MRI measurements of partial pressure of CO2 in surface waters of the Pacific during 1968–70: re-evaluation and comparison of data with those of the 1980s and 1990s

Article English OPEN
Inoue, Hisayuki Yoshikawa ; Ishii, Maso ; Matsueda, Hidekadzu ; Saito, Shu ; Midorikawa, Takashi ; Nemoto, Kazuhiro (2011)

During 1968 to 72, scientists of the Meteorological Research Institute/Japan Meteorological Agency measured CO2 in the surface seawater and overlying air in the Pacific Ocean quasicontinuously to examine CO2 exchange between the sea and the atmosphere. From the data remaining in our laboratory from that time, we re-evaluated the partial pressure of CO2 in surface seawater (pCOs2) by taking into account pressure broadening effects due to the use of CO2-in-N2 standards, the use of chemical desiccant (Mg(ClO4)2), calibration using background air data, seawater temperature rise between the equilibrator and sea surface, the WMO CO2 mole fraction scale, and differences in pressure during the oceanic CO2 measurements from those of standards and background air in the nondispersive infra-red gas analyser cell. The overall uncertainty of pCOs2 measurements for the cruises from 1968 to 1970 was estimated to be less than 3.6 μatm, which allowed us to evaluate temporal variations in the carbonate system over a few decades, but uncertainty was higher (> 10 μatm) for the cruise from 1971 to 1972 because of serious malfunctions of the system. The re-evaluated pCOs2 data from 1968 to 1970 exhibit patterns similar to those observed at the same place and time of year (within 30 days) in 1982/83, 1988, 1995 and 1996, but compared with levels in the 1980s and 1990s the pCOs2 level was clearly lower in the wide area of the Pacific except south of the Subtropical Front (STF; 47°S) in the Australian sector. The observed pCOs2 increased by 34 ± 5 μatm (n = 133) for the area 7°N to 35°N, 138°E to 147°E from February 1969 to February 1995, 29 ± 5 μatm (n = 247) for the area 9°N to 35°N, 138°E to 165°E from February 1970 to February/March 1996, 26 ± 7 μatm (n = 224) for the area 29°N to 51°N, 170°W from April 1970 to April 1988, and 41 ± 9 μatm (n = 165) for the area 10°S to 45°S, 148°E to 166°E from January/February 1969 to January/February 1995. In the northern subtropics (7°N to 35°N, 138°E to 147°E), we estimated the long-term increase (35 ± 6 μatm, n= 133) after removing seasonal variations that were obtained from the pCOs2-sea surface temperature (SST) relationship. Observed and seasonally adjusted increases were nearly equal to those of the partial pressure of CO2 in the air (1.4 μatm yr−1) over the same time intervals. South of the STF, pCOs2 increase as found in the subtropics was not detected, mostly due to the large variability of pCOs2 (250 to 380 μatm in 1968/69) on small spatial scales. The average pCOs2 south of the STF showed large variations on time scales of months and years that affect the estimation of the growth rate of atmospheric CO2.DOI: 10.1034/j.1600-0889.1999.t01-3-00007.x
  • References (48)
    48 references, page 1 of 5

    Bingham, F. M. 1992. Formation and spreading of subtropical mode water in the North Pacific. J. Geophys. Res. 97, 11,177-11,189.

    Broecker, W. S., Peng, T., O¨stlund, G. and Stuiver, M. 1985. The distribution of bomb radiocarbon in the ocean. J. Geophys. Res. 90, 6953-6970.

    Intergovernmental Panel on Climate Change (IPCC) 1996. Climate change 1995. T he science of climate change. Contribution of working group I to the second assessment report of the Intergovernmental Panel on Climate Change (eds. J. T. Houghton, L. G. Meira Filho, B. A. Callender, N. Harris, A. Kattenberg and K. Maskell ). Cambridge University Press, Cambridge.

    Conway, T. J., Tans, P. P., Waterman, L. S., Thoning, K. W., Kitzis, D. R., Masarie, K. A. and Zhang, N. 1994. Evidence for interannual variability of the carbon cycle from the National Oceanic and Atmospheric Administration/Climate Monitoring and Diagnostics Laboratory global air sampling network. J. Geophys. Res. 99, 22,831-22,855.

    Copin-Montegut, C. 1988. A new formula for the eVect of temperature on the partial pressure of CO2 in seawater. Mar. Chem. 25, 29-37.

    Copin-Montegut, C. 1989. Corrigendum. Mar. Chem. 27, 143-144.

    Dickson, A. G. 1994. The Plastic Menagerie: CO2 Teams Compare Seagoing Systems. US JGOFS News. 5, no. 4, 5.

    DOE. 1994. Handbook of methods for the analysis of the various parameters of the carbon dioxide in sea water; version 2 (eds. A. G. Dickson and C. Goyet). ORNL/ CDIAC-74. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn.

    Feely, R. A., Gammon, R. H., Taft, B. A., Pullen, P. E., Waterman, L. S., Conway, T. J., Gendron, J. F. and Wisegarver, D. P. 1987. Distribution of chemical tracers in the eastern equatorial Pacific during and after the 1982-83 El Ni n˜o/Southern Oscillation Event. J. Geophys. Res. 92, 6545-6558.

    Feely, R. A., Wanninkhof, R., Cosca, C. E., Murphy, P. P., Lamb, M. F. and Steckey, M. D. 1995. CO2 distributions in the equatorial Pacific during the 1991-1992 ENSO event. Deep-Sea Res. 42, 365-386.

  • Metrics
    No metrics available
Share - Bookmark