Simpleice microphysics - parameters differ from cited references

[fjansson]

In modsimpleice.f90, subroutine evapdep, the coefficients for the ventilation factor for snow differs from the values in the references.

ventr=.78*n0rr/lambdar(i,j,k)**2 + gam2dr*.27*n0rr*sqrt(ccrz(k)/2.e-5)*lambdar(i,j,k)**(-2.5-0.5*ddr)
vents=.78*n0rs/lambdas(i,j,k)**2 + gam2ds*.27*n0rs*sqrt(ccsz(k)/2.e-5)*lambdas(i,j,k)**(-2.5-0.5*dds)
ventg=.78*n0rg/lambdag(i,j,k)**2 + gam2dg*.27*n0rg*sqrt(ccgz(k)/2.e-5)*lambdag(i,j,k)**(-2.5-0.5*ddg)

For rain and graupel, the values match the references. For snow, 0.78 -> 0.65, and 0.27 -> 0.39, according to Grabowski 1998 and
Tomita 2008.

[fjansson]

This has been fixed in version 4.2, the simpleice2 scheme, usable with imicro=6. note that the original simpleice scheme with imicro=5 has not been changed.