Miranda, R. C.. Instituto Superior Tecnico, rmiranda@hidro1.ist.utl.pt
Neves, R. C.. Instituto Superior Tecnico, ramiro.neves@hidro1.ist.utl.pt

 
NITROGEN BIOGEOCHEMICAL CYCLE ON THE NORTH ATLANTIC OCEAN
 
We developed a biogeochemical model of the nitrogen annual cycle that can be easily coupled to different transport models. The model was calibrated for the Goban Spur area using the eulerian and lagrangean approaches. It was initially coupled to a 1-D vertical hydrodynamic model that solves the turbulence using a k-1 model. The model results agree with the Sverdrup's mechanism for temperate waters and show additionally the development of a phytoplankton sub-superficial maximum near the thermocline. Later, the biogeochemical model was coupled to a 3-D lagrangean model giving a regional scale view of the processes involved. This approach enabled the simulation of horizontal gradients of phytoplankton productivity that are in agreement with average values measured by the CZCS for this area in July. The lagrangean approach allows the tracing of the trajectory of individual particles. These particles are small water masses that are exposed to different light intensities due to vertical mixing. Their only way to take-up nutrients is by molecular diffusion or small-scale turbulent diffusion (of the order of magnitude of the dimension of each particle). We suggest a new approach where a sub-model is coupled to each particle and simulates the biogeochemical processes at and below the Kolmogorov scale.
 
Day: Tuesday, Feb. 2
Time: 10:45 - 11:00am
Location: Hilton of Santa Fe
 
Code: SS02TU1045H