pt,s_interior_formulation options:

'restoring'

a simple restoring of the potential temperature or salinity below the top level in the model to a data value, d(T,S)/dt = ((T,S)_data - (T,S)_model) / τ, where τ is a constant time scale. Values of the potential temperature or salinity in the entire volume of the ocean ((T,S)_data) are the only necessary forcing fields. If this option is chosen, then a value for the restoring time scale namelist variable pt,s_interior_restore_tau (in days) also needs to be specified. In addition, a value for the namelist variable which specifies the maximum level for which interior restoring is performed (pt,s_interior_restore_max_level) is necessary. For example, if s_interior_restore_tau=365 and s_interior_restore_max_level=17, then salinity will be restored to data with a time scale of one year for model levels 2 through 17 everywhere in the ocean.

Having interior restoring occur everywhere in the ocean as described above is more relevant to data-assimilation than to prognostic simulations, so there is support for variable interior restoring specified by

pt,s_variable_interior_restore = .true..

If this option is selected, the user must supply a file

pt,s_interior_restore_filename

that contains the maximum model depth for which interior restoring is performed and the inverse restoring timescale (1/days) for each horizontal grid point. This option can be useful for creating graduated 'buffer zones' at the boundaries of non-global models or to set water mass properties due to outflow from unresolved marginal seas.For example, the maximum level for restoring can be set to zero everywhere except for north of 75N where it takes on a nonzero (though not necessarily constant from point to point) value to help create Arctic water masses. To reduce the direct influence of the buffer zone, the inverse restoring time-scale can be tapered from zero at 75N to a finite value at the northern edge of the grid. Note that the code expects both fields to be double precision, but converts the maximum depth-level field to integer internally to the nearest integer.