em_quarter_ss test case:

This test case produces a simulation of a supercell
thunderstorm.  The environmental wind makes a
"quarter circle" when plotted on a hodograph, and
is commonly referred to as "quarter circle shear".
"ss" refers to "super-cell".

The default version of this test case uses a constant
eddy viscosity for turbulent mixing -> 
diff_opt=1 and km_opt = 1 in namelist.input.
The Coriolis terms in the model are off (f = 0)

The prognostic TKE can be activated by setting
diff_opt=2 and km_opt = 2 (see README.namelist).

In idealized cloud model simulations, it is common practice
to use Coriolis forcing calculated from wind fields defined
as perturbations from the initial sounding.  This option
can be activated by setting the "dynamics" namelist option
"pert_coriolis = .true."  (the default is false).
Additionally, the value of the Coriolis parameter "f"
will need to be reset (from zero to the desired value)
in WRFV1/dyn_em/module_initialize_quarter_ss.F, and
the initial state recomputed.

Also, a constant surface drag and heat flux can be specified
in the TKE formulation by setting the "dynamics" namelist option
"tke_drag_coefficient = Cd",
"tke_heat_flux = S".
The default values are zero.  Please note that these are 
specified constants; the formulations do not make use of
similarity theory.  These momentum and heat fluxes will 
not be active if surface and boundary layer formulations are
activated in the model physics.

The sounding used in this case is from Weisman and Klemp, MWR 1982, 504-520,
with subtle different in mixing ratio above troposphere.
