Turning TMS on in SD and SC compsets

[mmills@ucar_edu]

CESM-WACCM is set up to run with turbulent mountain stress (TMS) turned on, to parameterize the effect of unresolved orography as a surface stress. Turning on TMS in CESM-WACCM led to an improvement in the frequency of sudden stratospheric warmings compared to previous versions of WACCM, in which TMS was turned off.

TMS has been turned off, however, in the specified dynamics (SD) and specified chemistry (SC) compsets, F_SD_WACCM_CN and F_2000_WACCM_SC, for releases CESM1.0 through 1.0.4. Users may wish to turn TMS on for such runs, which can be done by setting the correct namelist variables with a user_nl_cam:

&phys_ctl_nl
 do_tms         =  .true.
 tms_orocnst            =  1.0D0
 tms_z0fac              =  0.100D0
/

Future releases will have TMS turned on by default in all WACCM compsets.