A 3-dimensional isopycnic coordinate model of the seasonal cycling of carbon and nitrogen in the Atlantic Ocean

Abstract Chemistry and pelagic ecosystem modules have been coupled to an isopycnic coordinate ocean general circulation model (OGCM) in order to model the seasonal cycling of carbon and nitrogen, and the associated organic and inorganic carbon and nitrogen fluxes, in the Atlantic Ocean. After an initial 20 years spin-up integration of the physical model, some of the results of a 5 years integration of the coupled model are presented. Comparison with in situ observations of nitrate, total dissolved inorganic carbon and surface water partial pressure of CO 2 indicate that the model reproduces the main features of the seasonal cycling of plant nutrients and carbon over large parts of the model domain. The model predicts that the Atlantic Ocean acts as a net sink of atmospheric CO 2 north of about 30°N (uptake of about 0.35 Pg-C yr −1 ), whereas there is an outgassing of CO 2 in the tropical region.

[1]  T. R. Anderson.  Modelling the influence of food C:N ratio, and respiration on growth and nitrogen excretion in marine zooplankton and bacteria , 1992 .

[2]  D. L. Aksnes,et al.  A coupled physical-biological pelagic model of a shallow sill fjord , 1990 .

[3]  P. Lamb.  On the mixed-layer climatology of the north and tropical Atlantic , 1984 .

[4]  R. Wanninkhof.  Relationship between wind speed and gas exchange over the ocean , 1992 .

[5]  W. R. Holland,et al.  Modeling the Wind and Thermohaline Circulation in the North Atlantic Ocean , 1994 .

[6]  F. A. Richards,et al.  The influence of organisms on the composition of sea-water , 1963 .

[7]  L. Talley,et al.  The subpolar mode water of the North Atlantic , 1982 .

[8]  Taro Takahashi,et al.  Seasonal variation of CO2 and nutrients in the high-latitude surface oceans: A comparative study , 1993 .

[9]  W. Grabowski,et al.  The multidimensional positive definite advection transport algorithm: nonoscillatory option , 1990 .

[10]  S. Levitus.  Climatological Atlas of the World Ocean , 1982 .

[11]  M. Fasham,et al.  Modelling the Marine Biota , 1993 .

[12]  Timothy T. Takahashi,et al.  An Assessment of the Role of the North Atlantic as a CO $_{2}$ Sink [and Discussion] , 1995 .

[13]  Donald L. DeAngelis,et al.  The global carbon cycle. , 1990 .

[14]  John H. Steele,et al.  The Significance of Interannual Variability , 1993 .

[15]  Allan R. Robinson,et al.  Ocean processes in climate dynamics : global and mediterranean examples , 1994 .

[16]  S. Levitus,et al.  World ocean atlas 1994. Volume 1, Nutrients , 1994 .

[17]  S. Levitus,et al.  Distribution of nitrate, phosphate and silicate in the world oceans , 1993 .

[18]  Ann E. Gargett,et al.  Vertical eddy diffusivity in the ocean interior , 1984 .

[19]  David M. Karl,et al.  VERTEX: carbon cycling in the northeast Pacific , 1987 .

[20]  W. Broecker,et al.  Seasonal variability of carbon dioxide, nutrients and oxygen in the northern North Atlantic surface water: observations and a model* , 1987 .

[21]  L. Jaeger,et al.  Monatskarten des Niederschlags für die ganze Erde , 1976 .

[22]  M. Bender,et al.  Tracers in the Sea , 1984 .

[23]  J. Toggweiler,et al.  A seasonal three‐dimensional ecosystem model of nitrogen cycling in the North Atlantic Euphotic Zone , 1993 .

[24]  E. Maier‐Reimer,et al.  Geochemical cycles in an Ocean General Circulation Model , 1993 .

[25]  J. Stone.  Climate change 1995: The science of climate change. Contribution of working group I to the second assessment report of the intergovernmental panel on climate change , 1997 .

[26]  H. Ducklow,et al.  A nitrogen-based model of plankton dynamics in the oceanic mixed layer , 1990 .

[27]  Philippe Gaspar,et al.  Modeling the Seasonal Cycle of the Upper Ocean , 1988 .

[28]  Rainer Bleck,et al.  Salinity-driven Thermocline Transients in a Wind- and Thermohaline-forced Isopycnic Coordinate Model of the North Atlantic , 1992 .

[29]  B. Peterson,et al.  Particulate organic matter flux and planktonic new production in the deep ocean , 1979, Nature.

[30]  Sol Hellerman,et al.  Normal Monthly Wind Stress Over the World Ocean with Error Estimates , 1983 .

[31]  L. Lundberg.  CO2 air-sea exchange in the nordic seas - an attempt to make an estimate based on data , 1994 .

[32]  J. Houghton,et al.  Climate change 1995: the science of climate change. , 1996 .