Numerical modeling

Modeling activities

Numerical models will be used to better understand the observation obtained during the cruises. The data sampled during the cruises will also be used for model evaluation and improvement. The model activity will concentrate on investigating:

(1) investigating the vertical structure of the mesoscale biological and physical activity.
(2) studying the net regional effect of eddies on biological production.

(1) To investigate vertical structure, we will perform a series of experiments with passively floating and actively moving particles. The idea is that this will shed light on how sinking particles, plankton, and foraging organisms will distribute in relation to the mesoscale activity. The resulting particle distribution of will be compared with measured data of biomass from the acoustics. These numerical experiment are currently being set up.

(2) We will quantify the net effect of eddies on biological production on the Norwegian coast. Phytoplankton quickly responds to the injection of nutrients to the surface, and any effects of the mesoscale activity on primary production should be readily detectable. To get reliable values, or range of values, this effect will be investigated two different model setups: a 2-way coupled phytoplankton-zooplankton model with 4 km resolution (ROMS) and a 2km resolution layered ocean model with prescribed grazing fields (HYCOM). These numerical experiments will start in 2010.

Nitrate distribution in an anticyclonic eddy off the
coast of Norway, simulated using HYCOM-NORWECOM
Copepod distribution after 1 year of simulation with
the coupled ROMS-NORWECOM-IBM_calanus model system.

Model systems

For the physcical simulations the full-scale ocean models, ROMS and HYCOM are used. These are both coupled to the phytoplankton model NORWECOM and an IBM model for Calanus finmarchicus. In the ROMS model the two biological modules are coupled, this is not the case in HYCOM. Passively floating particles will also be used to study how passively floating material behave within mesoscale activity

To represent the mesoscale activity we will use nested models with resolution of 2-4 km.