Another sub-option for varhmix is
option am_taper_highlats. This option keeps the viscosity
constant until reaching a specified latitude, defaulted to
,
and then will taper the viscosity quadratically poleward
until it reaches a fraction of the namelist viscosity. Details of the
function used to taper are easily altered, and they are specified in
the Smagorinsky fortran routine, along with option am_cosine