MODELING THE SEASONAL COURSE OF THE UPPER OCEAN PCO(2) .2. VALIDATIONOF THE MODEL AND SENSITIVITY STUDIES

A one-dimensional model was developed, aiming at the simulation of the seasonal course of the upper-ocean pCO(2). This model is validated he re, by comparing its outputs with field data. at the Ocean Weathership Station Papa in the Northeast Pacific Ocean (from 1975 to 1977). This simulation emphazises the leading role of biology in changing the ino rganic carbon content at this station, compared to those of eddy diffu sivity, entrainment and air-sea exchange. Complex and intricated depen dences of pCO(2) variations on temperature, Sigma CO2 and TA are analy sed. On the occasion of a comparison of the model with that of Taylor et al., the pitfalls of univocal correlations between the sea-surface pCO(2). temperature and Chl at a given site are put in evidence on the basis of their complex and divergent annual evolutions. Sensitivity t ests quantitatively show the importance for the model of (i) the repre sentation of the chlorophyll cycle, (ii) the mean value selected for t he f-ratio. Some possible developments of the model, and its applicati ons in view of assimilating remotely-sensed data are discussed.