Estimating pCO2 from sea surface temperatures in the Atlantic gyres

A simple one-dimensional model, validated with observations from ship of opportunity programs, was run at different locations in the North and South Atlantic gyres to produce seasonal partial pressure of CO2 (pCO2)–sea surface temperature (SST) relationships. The pCO2–SST relationships obtained at different locations in the North Atlantic gyre can be approximated by two regression lines, one from February to July and another from August to January. An algorithm including SST, latitude, longitude and atmospheric pCO2 was constructed for each period. The robustness of these relationships was tested along several transects in the North Atlantic gyre and found to be in good agreement with the observations. The same approach was used in the South Atlantic gyre, but more observations are required in this region. In both gyres, the pCO2–SST relationships are close to 4%/1C, which is higher than the pCO2– SST relationships deduced from a CO2 climatology. r 2002 Elsevier Science Ltd. All rights reserved.

[1]  Richard J. Geider,et al.  Seasonal and latitudinal dependencies of phytoplankton carbon-to-chlorophyll a ratios: results of a modelling study , 1997 .

[2]  S. Levitus.  Yearly and year-season upper ocean temperature anomaly fields, 1948-1998 , 2000 .

[3]  A. Knap,et al.  Variability of pCO2 on diel to seasonal timescales in the Sargasso Sea near Bermuda , 1998 .

[4]  S. Doney.  The ocean's productive deserts , 1997, Nature.

[5]  N. Metzl,et al.  Spatio‐temporal distributions of air‐sea fluxes of CO2 in the Indian and Antarctic oceans , 1995 .

[6]  R. Healy,et al.  Global Distribution of Total Inorganic Carbon and Total Alkalinity below the Deepest Winter Mixed Layer Depths , 2000 .

[7]  C. D. Keeling,et al.  Seasonal effects of temperature and salinity on the partial pressure of CO2 in seawater , 1982, Nature.

[8]  F. Millero,et al.  A comparison of the equilibrium constants for the dissociation of carbonic acid in seawater media , 1987 .

[9]  T. Kana,et al.  Dynamic model of phytoplankton growth and acclimation: responses of the balanced growth rate and the chlorophyll a:carbon ratio to light, nutrient-limitation and temperature , 1997 .

[10]  A. Watson,et al.  Variability of pCO2 in the tropical Atlantic in 1995 , 1998 .

[11]  A. Watson,et al.  The influence of the spring phytoplankton bloom on carbon dioxide and oxygen concentrations in the surface waters of the northeast Atlantic during 1989 , 1992 .

[12]  I. Fung,et al.  Observational Contrains on the Global Atmospheric Co2 Budget , 1990, Science.

[13]  A. Morel.  Optical modeling of the upper ocean in relation to its biogenous matter content (case I waters) , 1988 .

[14]  A. Knap,et al.  Alkalinity changes in the Sargasso Sea: geochemical evidence of calcification? , 1996 .

[15]  N. Metzl,et al.  Spatio-temporal distributions of air-sea fluxes of CO2 in the Indian and Antarctic oceans: a first step , 1995 .

[16]  D. Antoine,et al.  Modelling the seasonal course of the upper ocean pCO2 (II). Validation of the model and sensitivity studies , 1995 .

[17]  C. Copin-Montégut.  A new formula for the effect of temperature on the partial pressure of CO2 in seawater , 1988 .

[18]  A. Watson,et al.  Variation of PCO2 along a North Atlantic shipping route (U.K. to the Caribbean) : A year of automated observations , 1998 .

[19]  C. Culberson,et al.  MEASUREMENT OF THE APPARENT DISSOCIATION CONSTANTS OF CARBONIC ACID IN SEAWATER AT ATMOSPHERIC PRESSURE1 , 1973 .

[20]  C. Goyet,et al.  Distribution of carbon dioxide partial pressure in surface waters of the Southwest Indian Ocean , 1991 .

[21]  R F Weiss,et al.  Global air-sea flux of CO2: an estimate based on measurements of sea-air pCO2 difference. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[22]  J. Stephens,et al.  Diurnal variations of convective mixing and the spring bloom of phytoplankton , 1993 .

[23]  A. Watson,et al.  A modelling investigation of the role of phytoplankton in the balance of carbon at the surface of the North Atlantic , 1991 .

[24]  D. Wallace,et al.  Carbon dioxide, hydrographic, and chemical data obtained during the R/V Meteor cruise 15/3 in the South Atlantic Ocean. WOCE Section A9, February--March 1991 , 1995 .

[25]  N. Lefèvre,et al.  Distribution of the CO2 partial pressure along an Atlantic meridional transect , 2000 .

[26]  F. Millero.  Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Hesperides Cruise in the Atlantic Ocean , 2000 .

[27]  L. Gordon,et al.  The effect of temperature on carbon dioxide partial pressures in seawater , 1973 .

[28]  R. Feely,et al.  Low interannual variability in recent oceanic uptake of atmospheric carbon dioxide , 1998, Nature.

[29]  D. Olson,et al.  Sea-air flux of CO2 in the North Pacific using shipboard and satellite data , 1995 .