Biomass data assimilation set-up and performances

In the framework of the European Union MFSTEP Project regarding the Mediterranean Forecasting System in the direction of forecasting of the environmental and ecological variables, the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS in Trieste has actively cooperated with the CINECA Supercomputing Group in Bologna for determining a coupled hydrodynamical and ecological model in the Mediterranean Sea based upon inorganic and organic nitrogen, and on plankton in the same nitrogen units, moreover for optimising the computing resources and managing the outputs. 100 CPU hours have been used during the first set-up phase in the 2004 for assimilating phytoplankton data in the simulation with modified initial conditions, i. e. different from the reference simulation ones. During the second phase, the effects along decadal times upon total nitrogen content have been evaluated. The organic and inorganic matter inputs at surface induce really stable equilibrium situation of the ecosystem at longer times, after more than thirty years of dynamics, using about 500 hours of computing time on the new platform IBM SP5.