SCAM with Nudging

[rphani@tropmet_res_in]

Running SCAM for IOP cases in CAM5 successfully with the option "-dyn eul".
Can we include nudging for SCAM IOP apart from the forcing with "iopfile".
For this included the below and tried different options "-dyn fv -offline_dyn" and not successful.
&metdata_nl
met_data_file = '2011/GEOS5.1_19x2_20110101.nc'
met_data_path = 'xxxxx/cesm/inputdata/atm/cam/met/GEOS5' ; This is the location of the GEOS5 files
met_filenames_list = 'xxxxx/cesm/inputdata/atm/cam/met/GEOS5/filenames_list.txt' ; create a filename_list.txt file that points to the GEOS5 data
met_max_rlx = 0.10 ; nudging factor

Is it possible to have nudging in CAM5 or CAM6 for SCAM IOP cases.

PHAN

 

[brianpm]

I'm not entirely sure I understand what you are wanting to do. What quantities would you want to nudge? The IOP files provide a strong constraint by specifying the winds. You can optionally specify to use other quantities. For example by setting `scm_use_obs_qv` to use the specified water vapor or `scm_use_obs_T` to use the specified temperature. See the list of namelist options available in CAMROOT/src/control/scamMod.F90.

There is an additional option within SCAM to apply a relaxation timescale to a layer, and it can use either a specified time or a linear relaxation time. You can take a look at this in CAMROOT/src/dynamics/eul/scmforecast.F90 and look for the area that is conditioned on `scm_relaxation`. That allows for relaxation of T, Q, U, V.

Between specifying what to use from the IOP file and the additional relaxation options, I suspect you can achieve the result you are looking for.

At this time, SCAM requires the "-dyn eul" option as far as I know. I think this is because it relies on that dynamical core for vertical advection methods.