; LOSINTABS performs Line-Of-Sight INTegration including ABSorption ; S. C. Solomon, 10/04 ; Assumes no horizontal dependence of emission function ; Uses rectangular integration at 20 km intervals along observation path ; Input: ; zs observation altitude, in cm, above center ; zr array of emission heights, in cm, above center ; eta array of emission rates, in phot/cm3/s ; den array of absorbing species densities, in cm-3 ; sigma absorption cross section, in cm2 ; Output: ; br array of limb brightness, in microRayleighs ; calculated at tangent distances equal to zr ; Brightness above zs is assumed to be zero PRO LOSINTABS, ZS, ZR, ETA, DEN, SIGMA, BR interval=20.*1.e5 n=n_elements(zr) br=fltarr(n) for i=0,n-1 do begin zm = zs < zr[n-1] if zm gt zr[i] then begin smax = 2. * sqrt(zm^2 - zr[i]^2) nint = fix(smax/interval) if nint gt 0 then begin s = findgen(nint)*interval z = sqrt((smax/2-s)^2 + zr[i]^2) e = interpol(eta,zr,z) > 0. d = interpol(den,zr,z) > 0. tau=fltarr(nint) for j=1,nint-1 do tau[j]=total(d[1:j]*interval*sigma) trans = exp(-tau) br(i) = interval*total(e*trans) endif else begin br[i]=0. endelse endif else begin br[i]=0. endelse endfor return end