friction()

subroutine module_smoke_plumerise::friction	(	integer	ifrom,
		integer	nm1,
		integer	deltak,
		real(kind=kind_phys)	dt,
		real(kind=kind_phys), dimension(nm1)	zt,
		real(kind=kind_phys), dimension(nm1)	zm,
		real(kind=kind_phys), dimension(nm1)	var1,
		real(kind=kind_phys), dimension(nm1)	vart,
		real(kind=kind_phys), dimension(nm1)	var2 )