i have a question about nudging

[kobl1201]

hello

when i want to use nudging method about 3d-field, shoud i need u and v values in climate_file??

if i need u,v values in clim_file, i can't slove this problem.

how can i do??

[kate]

You have choices. One option is to start by only nudging to T and S and see how that works for you. If you also need nudging to u,v, here are the dimensions of things for one of my files:

Code: Select all

dimensions:
        s_rho = 50 ;
        s_w = 51 ;
        eta_rho = 1090 ;
        xi_rho = 690 ;
        eta_u = 1090 ;
        xi_u = 689 ;
        eta_v = 1089 ;
        xi_v = 690 ;
        eta_psi = 1089 ;
        xi_psi = 689 ;
        ocean_time = UNLIMITED ; // (12 currently)

Code: Select all

        double salt(ocean_time, s_rho, eta_rho, xi_rho) ;
                salt:_FillValue = -9.98999971057742e+33 ;
                salt:long_name = "salinity" ;
                salt:units = "PSU" ;
                salt:field = "salinity, scalar, series" ;
                salt:time = "ocean_time" ;
        double u(ocean_time, s_rho, eta_u, xi_u) ;
                u:_FillValue = -9.98999971057742e+33 ;
                u:long_name = "3D u-momentum component" ;
                u:units = "meter second-1" ;
                u:field = "u-velocity, scalar, series" ;
        double ubar(ocean_time, eta_u, xi_u) ;
                ubar:_FillValue = -9.98999971057742e+33 ;
                ubar:long_name = "2D u-momentum component" ;
                ubar:units = "meter second-1" ;
                ubar:field = "ubar-velocity,, scalar, series" ;
        double v(ocean_time, s_rho, eta_v, xi_v) ;
                v:_FillValue = -9.98999971057742e+33 ;
                v:long_name = "3D v-momentum component" ;
                v:units = "meter second-1" ;
                v:field = "v-velocity, scalar, series" ;

Oops, I see I'm going to have to add a "time" attribute to all of these, making the velocities match salt. Anyway, all your horizontal dimensions should look something like this.

[wilkin]

There are CDL templates for the various ROMS files in the folder Data/ROMS/CDL (starting from the same level in the hierarchy where you see: Atmosphere, Data, Master, User, makefile ... ROMS etc.)

You can copy and edit those to match your grid dimensions, being careful to maintain the +/- 1 in the respective dimensions. Then create an empty netcdf file with, e.g.

ncgen -b -o myfile.nc template.cdl