Ocean carbon cycling in Eastern Boundary Current systems: the Canary vs the California Current System

Z. Lachkar (1), N. Gruber (1), G.-K. Plattner (1), H. Frenzel (2), and M. Muennich (1)

(1) Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland
(2) Institute of Geophysics and Planetary Physics, UCLA, Los Angeles CA, USA

(zouhair.lachkar@env.ethz.ch)

Eastern Boundary Currents Systems (EBCs) are major oceanographic features that are well known for their high productivity and for playing an important role in the marine carbon cycle. Yet, the quantitative understanding of the mechanisms driving biological production, air-sea CO2 fluxes, and offshore transport of organic matter in these systems is limited. Through a comparative study of the Canary Current System (CanCS) and the California Current System (CalCS), we investigate here the major environmental factors and the leading physical processes that control the biological production rates and the fate of the organic matter in each EBC. Our analyses are based on a series of Regional Oceanic Modeling System (ROMS) simulations in both EBCs, enhanced with analyses of remotely observed quantities such as chlorophyll and net primary production. In order to ensure that the coastal ocean dynamics is optimally represented, a first set of simulations was conducted to characterize the model sensitivity to resolution, atmospheric forcing, topography, and the open boundary conditions. A first validation of the simulated mean circulation and the seasonal cycle was realized by comparing model outputs with climatologies from satellite and in-situ data. It shows the skills of the model to reproduce the regional circulation and the seasonal cycle of coastal upwelling. In this presentation, we will describe the details of the implementation of the ROMS Canary Current model and will discuss the first preliminary results from the CanCS and CalCS comparison.