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Initial conditions

In order to simulate quite well the hydrodynamical circulation even at the earlier stages of the model run, the physical equations have been integrated on 2-year period from dummy initial conditions. The results of this spin-up have then been used as initial conditions for the real simulations. Those initial physical fields are presented at figures 5.2 to 5.5.

The initial conditions for the biological variables were set up as following :

Two passive tracers have been introduced in the model run :

  1. The first one is initially totally absent from the modelled area, with a constant unitary source situated at the rivers' mouth. The aim of this tracer is to follow the river plume into the ocean and compute the fraction of this unitary concentration flowing into the Mediterranean Sea. This will enable us to test the river input hypothesis formulated in [13]. This tracer will also enable us to compute the average transit time from the rivers' mouth to the Straits of Gibraltar and the Mediterranean Sea.
  2. The second tracer is initially released in the northern part of the Gulf of Cadiz, with an constant unitary concentration on the whole water column. It will enable us to determine the fate of the waters transitting the Gulf and the rate of their advection into the Mediterranean Sea. This will be usefull in order to check Van Geen's hypothesis of a fixation of trace metals by plankton and entrainment to the Mediterranean.

The initial conditions for the second tracer and nitrate for the Western half of the coarse model are shown at figure 5.6.

For the nested model, the initial conditions are obtained by interpolating the data of the complete domain on the coarse grid.

Figure 5.2: Initial free surface elevation

Figure 5.3: Initial shallow and deep velocity fields

Figure 5.4: Initial shallow and deep temperature fields

Figure 5.5: Initial shallow and deep salinity fields

Figure 5.6: Initial nitrate and tracer positions

next up previous contents
Next: External forcing Up: The simulations Previous: The grids

Wed Jun 10 10:53:44 DFT 1998