Non orographic gravity waves drag

Description of the physical process

Parametrization of the momentum flux deposition due to a discrete number of gravity waves randomly generated by setting their waves characteristics (set as Gaussian distribution).

In the code, the FORTRAN file corresponding to this parametrization is

nonoro_gwd_ran_mod.F90

Inherited and adapted from Earth's model (F. Lott), Venus' model (F. LOTT, and S. LEBONNOIS) and Mars' model (G.GILLI, F. FORGET and D.BARDET). Parametrization implemented in the Generic PCM by D.BARDET is the case of Giant Planets and updated J.LIU

Underlying hypotheses and limitations

• input flux compensated in the deepest layers
• Variable EP-flux according to PBL variation (max velocity thermals)
• reproductibility of the launching altitude calculation
• wave characteristic calculation using MOD
• adding east_gwstress and west_gwstress variables
• The rho (density) at the specific locations is introduced. The equation of EP-flux is corrected by adding the term of density at launch (source) altitude(level)

Inputs and outputs of the module

! 0.1 INPUTS
     INTEGER, intent(in):: ngrid           ! number of atmospheric columns
     INTEGER, intent(in):: nlayer          ! number of atmospheric columns
     REAL, intent(in):: dtime              ! Time step of the Physics
     REAL, intent(in):: zmax_therm(ngrid)  ! Altitude of max velocity thermals (m)
     REAL,INTENT(IN) :: cpnew(ngrid,nlayer)! Cp of the atmosphere
     REAL,INTENT(IN) :: rnew(ngrid,nlayer) ! R of the atmosphere
     REAL, intent(in):: pp(ngrid, nlayer)  ! Pressure at full levels(Pa)
     REAL, intent(in):: pt(ngrid, nlayer)  ! Temperature at full levels(K)
     REAL, intent(in):: pu(ngrid, nlayer)  ! Zonal wind at full levels(m/s)
     REAL, intent(in):: pv(ngrid, nlayer)  ! Meridional wind at full levels(m/s)
     REAL, intent(in):: pdt(ngrid, nlayer) ! Tendency on temperature(K/s)
     REAL, intent(in):: pdu(ngrid, nlayer) ! Tendency on zonal wind(m/s/s)
     REAL, intent(in):: pdv(ngrid, nlayer) ! Tendency on meridional wind(m/s/s)
! 0.2 OUTPUTS
     REAL, intent(out):: zustr(ngrid)         ! Zonal surface stress
     REAL, intent(out):: zvstr(ngrid)         ! Meridional surface stress
     REAL, intent(out):: d_t(ngrid, nlayer)   ! Tendency on temperature (K/s) due to gravity waves (not used set to zero)
     REAL, intent(out):: d_u(ngrid, nlayer)   ! Tendency on zonal wind (m/s/s) due to gravity waves
     REAL, intent(out):: d_v(ngrid, nlayer)   ! Tendency on meridional wind (m/s/s) due to gravity waves

Dedicated flags to call in the callphys.def

To activate this parametrization:

You have to set the maximum value of the Eliassen-Palm flux that can be transported by the wave package:

epflux_max

Additional parameters can be also change in the callphys.def (do not worry if you do not want to change them, they have default values in the code)

sat ! default gravity waves saturation value = 1.  !!
cmax ! default gravity waves phase velocity value = 30.  !!
rdiss ! default coefficient of dissipation = 1 !!
kmax ! default Max horizontal wavenumber = 1.e-4 !!