Model study of coupled physical-biogeochemical variability in the Labrador Sea

Abstract

This thesis presents results from a model study of coupled physical-biogeochemical variability in the Labrador Sea. The coupled physical-biogeochemical ocean model (OPA-PISCES) is implemented for three monitoring stations in the Labrador Sea; two of these stations are located on the shelves of the western and eastern parts of the basin, whereas the third station is in the central Labrador Sea. The results of the hindcasting for 1994 are validated with available observations. The results of the sensitivity analysis suggest that the model response to parameter variations differs from region to region. The parameters with highest model sensitivity are identified for each station. The simulated seasonal variability of the low trophic level ecosystem dynamics and their relations to coupled physical-biogeochemical processes are discussed. The seasonal variability of dissolved inorganic carbon (DIC) is driven by the bloom drawdown of surface DIC and export through sinking, while the simulated surface pCO₂ concentration appears to be underestimated throughout the year. Besides the process study of the coupled physical-biogeochemical system at the selected regions in the Labrador Sea, the present study demonstrates the applicability of t he PISCES ocean biogeochemical model for regional coupled physical-biogeochemical modeling.