subroutine nst_module::cal_tztr	(	integer, intent(in)	kdt,
		real(kind=kind_phys), intent(in)	xt,
		real(kind=kind_phys), intent(in)	c_0,
		real(kind=kind_phys), intent(in)	c_d,
		real(kind=kind_phys), intent(in)	w_0,
		real(kind=kind_phys), intent(in)	w_d,
		real(kind=kind_phys), intent(in)	zc,
		real(kind=kind_phys), intent(in)	zw,
		real(kind=kind_phys), intent(in)	z,
		real(kind=kind_phys), intent(out)	tztr
	)