; ----------------------------------------------------------------------
; Set N2 for DAR_refwave (avoid having to calculate each time.
; Set the global variable N2_refwave  .
; This is good for 2km,P=600,T=7,f=8... (LAT=+/-30) from Allen ..
; (see nsx_difatmref)
;
function nsxng_set_N2_refwave
;  common nsx

  DAR_refwave = 12000.          ; warning - hardcoded here and in nsxng_constants
  R = 1.e+4 / DAR_refwave
  N2= 64.328 + (29498.1 / (146.0-(R*R))) + (255.4 / (41.0-(R*R)))
  N2= N2 * (600.0 * (1.0 + (1.049 - (0.0157*7.0)) * 600.0 * 1.e-6))
  N2= N2 / (720.883 * (1.0 + (0.003661*7.0))) ;
  N2_refwave = N2 / 1.e+6                     ;

  return, N2_refwave

end

;void nsx_set_N2_refwave()
;{
;/**/
;double R,N2;
;/**/
;R = 1.e+4 / DAR_refwave;
;N2= 64.328 + (29498.1 / (146.0-(R*R))) + (255.4 / (41.0-(R*R)));
;N2= N2 * (600.0 * (1.0 + (1.049 - (0.0157*7.0)) * 600.0 * 1.e-6));
;N2= N2 / (720.883 * (1.0 + (0.003661*7.0)));
;N2_refwave = N2 / 1.e+6;
;return
;}