about sea surface condition of T&S

[zhaoqian]

Dear all roms user:
I found in set_vbc.F that the flux condition(plus sst or sss for the purpose of flux correction sometimes) are used as the sea surface condition.
I want to konw that can SST and SSS be used directly as the sea surface condition, which is the same as POM. If can, where is the code?
Thank you!

[kate]

You are hoping to replace the topmost values of T & S directly into the model? We don't have that code. What does exist is a nudging on some timescale to some external values.

[feroda]

What does exist is a nudging on some timescale to some external values.

Hi Kate, What's that in ROMS code?

Another question that may not have been thoroughly summarized in the forum is "How to active heat flux and fresh water flux in ROMS?"(I might miss some key posts)

What CPPs are usually used to active the surface boundary fluxes for both T and S?

Thanks a lot.

[kate]

I expect the two most common choices are:

1. Analytic forms for the surface T and S fluxes with ANA_SSFLUX and ANA_STFLUX.

2. Computed surface fluxes with BULK_FLUXES, in which you have to provide air temperature, wind, and rainfall, etc.

If you ask for neither ANA_STFLUX nor BULK_FLUXES, ROMS will look in the forcing files for heat and salt fluxes. It's the same as the momentum fluxes which are provided analytically, from a file, or computed from atmospheric fields.

[feroda]

If you ask for neither ANA_STFLUX nor BULK_FLUXES, ROMS will look in the forcing files for heat and salt fluxes.

What I did is as follows:
close ANA_SSFLUX and ANA_STFLUX, while open QCORRECTION and SRELAXATION+SCORRECTION in the header file;

The forcing file has
surface net heat flux
sea surface temperature climatology, and
surface net heat flux sensitivity to SST
surface net freswater flux, (E-P) ---->>might a typo here for freshwater in ROMS;
sea surface salinity

Model blows up after several steps. After close SRELAXATION+SCORRECTION, the model does a pretty good job on SST. I do not know what happens to SSS relaxation there.

[kate]

Some options are more well-tested than others. I'm afraid you might not get a satisfactory answer here, but please post when you figure it out.

[zhaoqian]

You are hoping to replace the topmost values of T & S directly into the model?

Dear Kate and all:
Thanks for replying, and I know how the upper boundary conditions of T &S set in ROMS .
Yes! I want to use the use the values of T & S directly instead of using flux because of its bad quality in the shallow sea area. In my next work, I will open QCORRECTION and SCORRECTION and provide sst、sst and flux at the same time.
Qian

[feroda]

Presumably, it will be perfect to clamp SST&SSS in ROMS to the objective ones, in case not care about the air-sea interaction. That is also what POM does. However, ROMS may not agree with such a strong restriction. I have the impression that the model will get some NaN if the SST&SST in model are restored to the objective ones at unsuitable timescale.