| 1 | subroutine calc_rayleigh |
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| 2 | |
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| 3 | !================================================================== |
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| 4 | ! |
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| 5 | ! Purpose |
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| 6 | ! ------- |
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| 7 | ! Average the Rayleigh scattering in each band, weighting the |
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| 8 | ! average by the blackbody function at temperature tstellar. |
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| 9 | ! |
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| 10 | ! Authors |
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| 11 | ! ------- |
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| 12 | ! Robin Wordsworth (2010) |
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| 13 | ! Benjamin Charnay (2010) |
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| 14 | ! |
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| 15 | ! Called by |
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| 16 | ! --------- |
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| 17 | ! setspv.F |
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| 18 | ! |
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| 19 | ! Calls |
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| 20 | ! ----- |
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| 21 | ! none |
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| 22 | ! |
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| 23 | !================================================================== |
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| 24 | |
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| 25 | use radinc_h, only: L_NSPECTV |
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| 26 | use radcommon_h, only: WAVEV, BWNV, DWNV, tstellar, gastype, tauray, scalep |
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| 27 | |
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| 28 | implicit none |
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| 29 | |
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| 30 | #include "comcstfi.h" |
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| 31 | |
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| 32 | real*8 wl |
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| 33 | integer N,Nfine,ifine |
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| 34 | parameter(Nfine=500.0) |
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| 35 | real*8 :: P0 = 9.423D+6 ! Rayleigh scattering reference pressure in pascals. |
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| 36 | |
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| 37 | logical waverage |
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| 38 | real*8 tauconst,tauvar,tausum,tauwei,bwidth,bstart |
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| 39 | double precision df |
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| 40 | |
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| 41 | waverage=.true. ! do we perform a blackbody weighted average by band? |
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| 42 | |
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| 43 | if(waverage)then |
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| 44 | if(gastype(1).eq.'CO2')then |
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| 45 | print*,'Rayleigh scattering is for a CO2 atmosphere.' |
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| 46 | tauconst = (8.7/g)*1.527*scalep/P0 |
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| 47 | elseif(gastype(1).eq.'AIR')then ! AIR = Earth air |
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| 48 | print*,'Rayleigh scattering is for an Earth-like atmosphere.' |
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| 49 | tauconst = (9.81/g)*8.569E-3*scalep/(P0/93.0) |
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| 50 | else |
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| 51 | print*,'Rayleigh scattering not defined for gas type ',gastype(n) |
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| 52 | print*,'exiting.' |
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| 53 | call abort |
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| 54 | endif |
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| 55 | endif |
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| 56 | |
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| 57 | do N=1,L_NSPECTV |
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| 58 | |
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| 59 | if(waverage)then |
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| 60 | tausum = 0.0 |
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| 61 | tauwei = 0.0 |
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| 62 | bstart = 10000.0/BWNV(N+1) |
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| 63 | bwidth = (10000.0/BWNV(N)) - (10000.0/BWNV(N+1)) |
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| 64 | do ifine=1,Nfine |
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| 65 | wl=bstart+dble(ifine)*bwidth/Nfine |
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| 66 | |
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| 67 | if(gastype(1).eq.'CO2')then |
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| 68 | tauvar = (1.0+0.013/wl**2)/wl**4 |
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| 69 | elseif(gastype(1).eq.'AIR')then |
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| 70 | tauvar = (1.0+0.0113/wl**2+0.00013/wl**4)/wl**4 |
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| 71 | endif |
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| 72 | |
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| 73 | call blackl(dble(wl*1e-6),dble(tstellar),df) |
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| 74 | df=df*bwidth/Nfine |
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| 75 | tauwei=tauwei+df |
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| 76 | tausum=tausum+tauvar*df |
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| 77 | enddo |
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| 78 | TAURAY(N)=tauconst*tausum/tauwei |
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| 79 | else |
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| 80 | wl = WAVEV(N) |
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| 81 | if(gastype(1).eq.'CO2')then |
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| 82 | if(N.eq.1) print*,'Rayleigh scattering is for a CO2 atmosphere.' |
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| 83 | TAURAY(N) = (8.7/g)*(1.527*(1.0+0.013/wl**2)/wl**4)*scalep/P0 |
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| 84 | elseif(gastype(1).eq.'AIR')then ! AIR = Earth air |
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| 85 | if(N.eq.1) print*,'Rayleigh scattering is for an Earth-like atmosphere.' |
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| 86 | TAURAY(N) = (9.81/g)*(8.569E-3*(1.0+0.0113/wl**2+0.00013/wl**4)/wl**4)*scalep/(P0/93.0) |
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| 87 | else |
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| 88 | print*,'Rayleigh scattering not defined for gas type ',gastype(n) |
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| 89 | print*,'exiting.' |
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| 90 | call abort |
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| 91 | endif |
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| 92 | endif |
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| 93 | |
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| 94 | ! we multiply by scalep here (100) because plev, which is used in optcv, |
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| 95 | ! is in units of mBar, so we need to convert. |
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| 96 | end do |
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| 97 | |
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| 98 | end subroutine calc_rayleigh |
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