Wind stress components:
Taux,Tauy [N/m2] |
The wind stress is externally computed from the wind velocity (at 10m height) through bulk formula and is directly imposed as surface boundary condition for the momentum equations. It is intended to integrate calculations of these fluxes interactively later. Various formulation of the drag coefficient can be used. |
Net heat flux:
Qh [W/m2] |
The net heat flux "Qh" (positive downward) is split in 2 components (2 columns in the file): (1) "I_0" the short-wave radiation emitted by sun and (2) "heat" the heat flux including the contributions of the latent, sensible and infrared radiation (note that the albedo effect is already taken into account). This separation is required because "heat" is considered as a boundary condition at surface while "I_0" is a source term in the temperature equation. The surface fluxes are calculated externally so far, but their computation will be interactively integrated into GOTM later. |
Surface Salinity/Temperature:
SSS [psu], SST [deg] |
The model can also be forced by a restoring of T & S toward observed values (tprof, sprof) in the surface or bottom layer. The thickness of these layers is determined by the user. The condition is physically based for the heat flux (it corresponds to the Taylor expansion of Qh around SST at the first order) but has no physical meaning for the freshwater flux (which does not depend on SSS). |
Barotropic sea-surface gradient:
d(Zeta)/dx,d(Zeta)/dy [/] |
The barotropic components of the pressure gradient are derived from the slope of the sea surface. The latter can be imposed directly (from the observed sea level) or analytically (as a combination of harmonic components (M2, S2...). The external pressure gradient can also be indirectly recalculated by imposing time series of either velocity components at certain height above the bed depth mean velocities. The modelled velocity field will then exactly reproduce these velocities. |
Baroclinic pressure gradient:
dp/dx,dp/dy [N/m2] |
Imposed or reconstructed from observations. |
Sea-Surface elevation:
Zeta [m] |
The elevation is only used to adapt the grid size but is not producing any forcing. |
Depth profile of Temperature, Salinity:
T [deg], S [psu] |
The depth profiles of S & T (tprof, sprof) can also be used to force the model via a restoring toward observations on the whole water column (method known as robust diagnostic run). This method aims to mimic the effects of lateral fluxes of tracer (via horizontal advection/diffusion) that cannot be represented explicitly by 1D models. It should therefore be applied when the hypothesis of horizontal homogeneity (i.e. horizontal gradient are negligible) is not well verified!. In this case, the 1D simulations should not be given predictive value but should rather be viewed as a way to derive the turbulent field from an imposed density field. |
Depth profile of horizontal velocity:
u,v [m/s] |
The depth profiles of u,v are used to recover the pressure gradients. |
Turbulent dissipation:
Eps [m2/s3] |
New profilers can obseve the turbulence dissipation. The performances of the model can therefore be evaluated. |