| 1 | SUBROUTINE GFLUXV(DTDEL,TDEL,TAUCUMIN,WDEL,CDEL,UBAR0,F0PI,RSF, |
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| 2 | * BTOP,BSURF,FMIDP,FMIDM,DIFFV,FLUXUP,FLUXDN) |
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| 3 | |
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| 4 | |
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| 5 | C THIS SUBROUTINE TAKES THE OPTICAL CONSTANTS AND BOUNDARY CONDITIONS |
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| 6 | C FOR THE VISIBLE FLUX AT ONE WAVELENGTH AND SOLVES FOR THE FLUXES AT |
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| 7 | C THE LEVELS. THIS VERSION IS SET UP TO WORK WITH LAYER OPTICAL DEPTHS |
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| 8 | C MEASURED FROM THE TOP OF EACH LAYER. (DTAU) TOP OF EACH LAYER HAS |
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| 9 | C OPTICAL DEPTH TAU(N).IN THIS SUB LEVEL N IS ABOVE LAYER N. THAT IS LAYER N |
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| 10 | C HAS LEVEL N ON TOP AND LEVEL N+1 ON BOTTOM. OPTICAL DEPTH INCREASES |
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| 11 | C FROM TOP TO BOTTOM. SEE C.P. MCKAY, TGM NOTES. |
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| 12 | C THIS SUBROUTINE DIFFERS FROM ITS IR COUNTERPART IN THAT HERE WE SOLVE FOR |
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| 13 | C THE FLUXES DIRECTLY USING THE GENERALIZED NOTATION OF MEADOR AND WEAVOR |
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| 14 | C J.A.S., 37, 630-642, 1980. |
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| 15 | C THE TRI-DIAGONAL MATRIX SOLVER IS DSOLVER AND IS DOUBLE PRECISION SO MANY |
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| 16 | C VARIABLES ARE PASSED AS SINGLE THEN BECOME DOUBLE IN DSOLVER |
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| 17 | C |
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| 18 | C NLL = NUMBER OF LEVELS (NAYER + 1) THAT WILL BE SOLVED |
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| 19 | C NAYER = NUMBER OF LAYERS (NOTE DIFFERENT SPELLING HERE) |
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| 20 | C WAVEN = WAVELENGTH FOR THE COMPUTATION |
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| 21 | C DTDEL(NLAYER) = ARRAY OPTICAL DEPTH OF THE LAYERS |
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| 22 | C TDEL(NLL) = ARRAY COLUMN OPTICAL DEPTH AT THE LEVELS |
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| 23 | C WDEL(NLEVEL) = SINGLE SCATTERING ALBEDO |
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| 24 | C CDEL(NLL) = ASYMMETRY FACTORS, 0=ISOTROPIC |
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| 25 | C UBARV = AVERAGE ANGLE, |
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| 26 | C UBAR0 = SOLAR ZENITH ANGLE |
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| 27 | C F0PI = INCIDENT SOLAR DIRECT BEAM FLUX |
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| 28 | C RSF = SURFACE REFLECTANCE |
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| 29 | C BTOP = UPPER BOUNDARY CONDITION ON DIFFUSE FLUX |
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| 30 | C BSURF = REFLECTED DIRECT BEAM = (1-RSFI)*F0PI*EDP-TAU/U |
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| 31 | C FP(NLEVEL) = UPWARD FLUX AT LEVELS |
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| 32 | C FM(NLEVEL) = DOWNWARD FLUX AT LEVELS |
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| 33 | C FMIDP(NLAYER) = UPWARD FLUX AT LAYER MIDPOINTS |
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| 34 | C FMIDM(NLAYER) = DOWNWARD FLUX AT LAYER MIDPOINTS |
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| 35 | C added Dec 2002 |
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| 36 | C DIFFV = downward diffuse solar flux at the surface |
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| 37 | C |
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| 38 | !======================================================================! |
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| 39 | |
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| 40 | use radinc_h |
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| 41 | |
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| 42 | implicit none |
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| 43 | |
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| 44 | ! INTEGER NLP |
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| 45 | ! PARAMETER (NLP=101) ! MUST BE LARGER THAN NLEVEL |
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| 46 | |
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| 47 | REAL*8 EM, EP |
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| 48 | REAL*8 W0(L_NLAYRAD), COSBAR(L_NLAYRAD), DTAU(L_NLAYRAD) |
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| 49 | REAL*8 TAU(L_NLEVRAD), WDEL(L_NLAYRAD), CDEL(L_NLAYRAD) |
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| 50 | REAL*8 DTDEL(L_NLAYRAD), TDEL(L_NLEVRAD) |
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| 51 | REAL*8 FMIDP(L_NLAYRAD), FMIDM(L_NLAYRAD) |
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| 52 | REAL*8 LAMDA(L_NLAYRAD), ALPHA(L_NLAYRAD), XK1(L_NLAYRAD) |
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| 53 | REAL*8 XK2(L_NLAYRAD),G1(L_NLAYRAD), G2(L_NLAYRAD) |
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| 54 | REAL*8 G3(L_NLAYRAD), GAMA(L_NLAYRAD),CP(L_NLAYRAD),CM(L_NLAYRAD) |
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| 55 | REAL*8 CPM1(L_NLAYRAD),CMM1(L_NLAYRAD), E1(L_NLAYRAD) |
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| 56 | REAL*8 E2(L_NLAYRAD),E3(L_NLAYRAD),E4(L_NLAYRAD),EXPTRM(L_NLAYRAD) |
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| 57 | REAL*8 FLUXUP, FLUXDN |
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| 58 | REAL*8 FACTOR, TAUCUMIN(L_LEVELS), TAUCUM(L_LEVELS) |
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| 59 | |
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| 60 | integer NAYER, L, K |
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| 61 | real*8 ubar0, f0pi, rsf, btop, bsurf, g4, denom, am, ap |
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| 62 | real*8 taumax, taumid, cpmid, cmmid |
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| 63 | real*8 diffv |
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| 64 | |
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| 65 | C======================================================================C |
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| 66 | |
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| 67 | |
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| 68 | |
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| 69 | |
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| 70 | NAYER = L_NLAYRAD |
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| 71 | TAUMAX = L_TAUMAX !Default is 35.0 |
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| 72 | |
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| 73 | ! Delta-Eddington Scaling |
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| 74 | |
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| 75 | |
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| 76 | FACTOR = 1.0D0 - WDEL(1)*CDEL(1)**2 |
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| 77 | |
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| 78 | TAU(1) = TDEL(1)*FACTOR |
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| 79 | TAUCUM(1) = 0.0D0 |
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| 80 | TAUCUM(2) = TAUCUMIN(2)*FACTOR |
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| 81 | TAUCUM(3) = TAUCUM(2) +(TAUCUMIN(3)-TAUCUMIN(2))*FACTOR |
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| 82 | |
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| 83 | !Print*, 'TBbug wdel= ',WDEL |
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| 84 | !Print*, 'TBbug cdel= ',CDEL |
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| 85 | |
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| 86 | DO L=1,L_NLAYRAD-1 |
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| 87 | FACTOR = 1.0D0 - WDEL(L)*CDEL(L)**2 |
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| 88 | W0(L) = WDEL(L)*(1.0D0-CDEL(L)**2)/FACTOR |
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| 89 | COSBAR(L) = CDEL(L)/(1.0D0+CDEL(L)) |
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| 90 | DTAU(L) = DTDEL(L)*FACTOR |
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| 91 | TAU(L+1) = TAU(L)+DTAU(L) |
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| 92 | K = 2*(L+1) |
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| 93 | TAUCUM(K) = TAU(L+1) |
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| 94 | TAUCUM(K+1) = TAUCUM(K) + (TAUCUMIN(K+1)-TAUCUMIN(K))*FACTOR |
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| 95 | END DO |
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| 96 | !write(*,*),'gfluxv : cosbar=',COSBAR |
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| 97 | !write(*,*),'gfluxv : w0, factor=',W0(1),FACTOR |
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| 98 | !write(*,*),'gfluxv : wdel, cdel',WDEL(1),CDEL(1) |
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| 99 | |
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| 100 | |
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| 101 | ! Bottom layer |
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| 102 | |
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| 103 | L = L_NLAYRAD |
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| 104 | FACTOR = 1.0D0 - WDEL(L)*CDEL(L)**2 |
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| 105 | W0(L) = WDEL(L)*(1.0D0-CDEL(L)**2)/FACTOR |
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| 106 | COSBAR(L) = CDEL(L)/(1.0D0+CDEL(L)) |
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| 107 | DTAU(L) = DTDEL(L)*FACTOR |
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| 108 | TAU(L+1) = TAU(L)+DTAU(L) |
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| 109 | TAUCUM(2*L+1) = TAU(L+1) |
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| 110 | |
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| 111 | |
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| 112 | C WE GO WITH THE QUADRATURE APPROACH HERE. THE "SQRT(3)" factors |
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| 113 | C ARE THE UBARV TERM. |
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| 114 | |
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| 115 | DO L=1,L_NLAYRAD |
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| 116 | |
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| 117 | |
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| 118 | ALPHA(L)=SQRT( (1.0-W0(L))/(1.0-W0(L)*COSBAR(L)) ) |
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| 119 | ! write(*,*),'gfluxv : alpha = ',ALPHA(L) |
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| 120 | |
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| 121 | |
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| 122 | C SET OF CONSTANTS DETERMINED BY DOM |
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| 123 | |
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| 124 | G1(L) = (SQRT(3.0)*0.5)*(2.0- W0(L)*(1.0+COSBAR(L))) |
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| 125 | G2(L) = (SQRT(3.0)*W0(L)*0.5)*(1.0-COSBAR(L)) |
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| 126 | G3(L) = 0.5*(1.0-SQRT(3.0)*COSBAR(L)*UBAR0) |
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| 127 | |
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| 128 | |
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| 129 | c this is Quadrature |
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| 130 | c but the scaling is Eddington? |
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| 131 | |
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| 132 | LAMDA(L) = SQRT(G1(L)**2 - G2(L)**2) |
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| 133 | GAMA(L) = (G1(L)-LAMDA(L))/G2(L) |
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| 134 | END DO |
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| 135 | |
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| 136 | DO L=1,L_NLAYRAD |
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| 137 | G4 = 1.0-G3(L) |
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| 138 | DENOM = LAMDA(L)**2 - 1./UBAR0**2 |
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| 139 | |
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| 140 | C THERE IS A POTENTIAL PROBLEM HERE IF W0=0 AND UBARV=UBAR0 |
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| 141 | C THEN DENOM WILL VANISH. THIS ONLY HAPPENS PHYSICALLY WHEN |
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| 142 | C THE SCATTERING GOES TO ZERO |
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| 143 | C PREVENT THIS WITH AN IF STATEMENT |
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| 144 | |
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| 145 | IF ( DENOM .EQ. 0.) THEN |
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| 146 | DENOM=1.E-10 |
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| 147 | END IF |
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| 148 | |
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| 149 | |
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| 150 | AM = F0PI*W0(L)*(G4 *(G1(L)+1./UBAR0) +G2(L)*G3(L) )/DENOM |
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| 151 | AP = F0PI*W0(L)*(G3(L)*(G1(L)-1./UBAR0) +G2(L)*G4 )/DENOM |
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| 152 | |
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| 153 | C CPM1 AND CMM1 ARE THE CPLUS AND CMINUS TERMS EVALUATED |
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| 154 | C AT THE TOP OF THE LAYER, THAT IS LOWER OPTICAL DEPTH TAU(L) |
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| 155 | |
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| 156 | CPM1(L) = AP*EXP(-TAU(L)/UBAR0) |
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| 157 | CMM1(L) = AM*EXP(-TAU(L)/UBAR0) |
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| 158 | |
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| 159 | C CP AND CM ARE THE CPLUS AND CMINUS TERMS EVALUATED AT THE |
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| 160 | C BOTTOM OF THE LAYER. THAT IS AT HIGHER OPTICAL DEPTH TAU(L+1) |
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| 161 | |
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| 162 | CP(L) = AP*EXP(-TAU(L+1)/UBAR0) |
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| 163 | CM(L) = AM*EXP(-TAU(L+1)/UBAR0) |
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| 164 | |
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| 165 | END DO |
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| 166 | |
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| 167 | |
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| 168 | |
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| 169 | C NOW CALCULATE THE EXPONENTIAL TERMS NEEDED |
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| 170 | C FOR THE TRIDIAGONAL ROTATED LAYERED METHOD |
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| 171 | |
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| 172 | DO L=1,L_NLAYRAD |
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| 173 | !print*, 'TBbug=',TAUMAX,LAMDA(L),DTAU(L) |
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| 174 | EXPTRM(L) = MIN(TAUMAX,LAMDA(L)*DTAU(L)) ! CLIPPED EXPONENTIAL |
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| 175 | EP = EXP(EXPTRM(L)) |
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| 176 | |
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| 177 | EM = 1.0/EP |
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| 178 | E1(L) = EP+GAMA(L)*EM |
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| 179 | E2(L) = EP-GAMA(L)*EM |
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| 180 | E3(L) = GAMA(L)*EP+EM |
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| 181 | E4(L) = GAMA(L)*EP-EM |
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| 182 | END DO |
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| 183 | |
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| 184 | CALL DSOLVER(NAYER,GAMA,CP,CM,CPM1,CMM1,E1,E2,E3,E4,BTOP, |
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| 185 | * BSURF,RSF,XK1,XK2) |
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| 186 | |
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| 187 | C NOW WE CALCULATE THE FLUXES AT THE MIDPOINTS OF THE LAYERS. |
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| 188 | |
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| 189 | DO L=1,L_NLAYRAD-1 |
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| 190 | EXPTRM(L) = MIN(TAUMAX,LAMDA(L)*(TAUCUM(2*L+1)-TAUCUM(2*L))) |
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| 191 | |
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| 192 | EP = EXP(EXPTRM(L)) |
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| 193 | |
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| 194 | EM = 1.0/EP |
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| 195 | G4 = 1.0-G3(L) |
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| 196 | DENOM = LAMDA(L)**2 - 1./UBAR0**2 |
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| 197 | |
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| 198 | C THERE IS A POTENTIAL PROBLEM HERE IF W0=0 AND UBARV=UBAR0 |
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| 199 | C THEN DENOM WILL VANISH. THIS ONLY HAPPENS PHYSICALLY WHEN |
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| 200 | C THE SCATTERING GOES TO ZERO |
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| 201 | C PREVENT THIS WITH A IF STATEMENT |
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| 202 | |
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| 203 | |
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| 204 | IF ( DENOM .EQ. 0.) THEN |
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| 205 | DENOM=1.E-10 |
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| 206 | END IF |
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| 207 | |
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| 208 | AM = F0PI*W0(L)*(G4 *(G1(L)+1./UBAR0) +G2(L)*G3(L) )/DENOM |
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| 209 | AP = F0PI*W0(L)*(G3(L)*(G1(L)-1./UBAR0) +G2(L)*G4 )/DENOM |
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| 210 | |
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| 211 | C CPMID AND CMMID ARE THE CPLUS AND CMINUS TERMS EVALUATED |
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| 212 | C AT THE MIDDLE OF THE LAYER. |
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| 213 | |
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| 214 | TAUMID = TAUCUM(2*L+1) |
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| 215 | |
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| 216 | CPMID = AP*EXP(-TAUMID/UBAR0) |
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| 217 | CMMID = AM*EXP(-TAUMID/UBAR0) |
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| 218 | |
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| 219 | FMIDP(L) = XK1(L)*EP + GAMA(L)*XK2(L)*EM + CPMID |
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| 220 | FMIDM(L) = XK1(L)*EP*GAMA(L) + XK2(L)*EM + CMMID |
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| 221 | |
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| 222 | C ADD THE DIRECT FLUX TO THE DOWNWELLING TERM |
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| 223 | |
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| 224 | FMIDM(L)= FMIDM(L)+UBAR0*F0PI*EXP(-MIN(TAUMID,TAUMAX)/UBAR0) |
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| 225 | |
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| 226 | END DO |
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| 227 | |
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| 228 | C FLUX AT THE Ptop layer |
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| 229 | |
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| 230 | EP = 1.0 |
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| 231 | EM = 1.0 |
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| 232 | G4 = 1.0-G3(1) |
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| 233 | DENOM = LAMDA(1)**2 - 1./UBAR0**2 |
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| 234 | |
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| 235 | C THERE IS A POTENTIAL PROBLEM HERE IF W0=0 AND UBARV=UBAR0 |
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| 236 | C THEN DENOM WILL VANISH. THIS ONLY HAPPENS PHYSICALLY WHEN |
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| 237 | C THE SCATTERING GOES TO ZERO |
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| 238 | C PREVENT THIS WITH A IF STATEMENT |
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| 239 | |
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| 240 | IF ( DENOM .EQ. 0.) THEN |
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| 241 | DENOM=1.E-10 |
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| 242 | END IF |
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| 243 | |
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| 244 | AM = F0PI*W0(1)*(G4 *(G1(1)+1./UBAR0) +G2(1)*G3(1) )/DENOM |
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| 245 | AP = F0PI*W0(1)*(G3(1)*(G1(1)-1./UBAR0) +G2(1)*G4 )/DENOM |
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| 246 | |
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| 247 | C CPMID AND CMMID ARE THE CPLUS AND CMINUS TERMS EVALUATED |
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| 248 | C AT THE MIDDLE OF THE LAYER. |
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| 249 | |
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| 250 | CPMID = AP |
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| 251 | CMMID = AM |
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| 252 | |
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| 253 | FLUXUP = XK1(1)*EP + GAMA(1)*XK2(1)*EM + CPMID |
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| 254 | FLUXDN = XK1(1)*EP*GAMA(1) + XK2(1)*EM + CMMID |
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| 255 | |
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| 256 | C ADD THE DIRECT FLUX TO THE DOWNWELLING TERM |
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| 257 | |
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| 258 | fluxdn = fluxdn+UBAR0*F0PI*EXP(-MIN(TAUCUM(1),TAUMAX)/UBAR0) |
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| 259 | |
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| 260 | C This is for the "special" bottom layer, where we take |
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| 261 | C DTAU instead of DTAU/2. |
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| 262 | |
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| 263 | L = L_NLAYRAD |
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| 264 | EXPTRM(L) = MIN(TAUMAX,LAMDA(L)*(TAUCUM(L_LEVELS)- |
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| 265 | * TAUCUM(L_LEVELS-1))) |
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| 266 | |
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| 267 | EP = EXP(EXPTRM(L)) |
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| 268 | EM = 1.0/EP |
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| 269 | G4 = 1.0-G3(L) |
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| 270 | DENOM = LAMDA(L)**2 - 1./UBAR0**2 |
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| 271 | |
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| 272 | |
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| 273 | |
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| 274 | C THERE IS A POTENTIAL PROBLEM HERE IF W0=0 AND UBARV=UBAR0 |
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| 275 | C THEN DENOM WILL VANISH. THIS ONLY HAPPENS PHYSICALLY WHEN |
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| 276 | C THE SCATTERING GOES TO ZERO |
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| 277 | C PREVENT THIS WITH A IF STATEMENT |
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| 278 | |
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| 279 | |
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| 280 | IF ( DENOM .EQ. 0.) THEN |
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| 281 | DENOM=1.E-10 |
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| 282 | END IF |
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| 283 | |
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| 284 | AM = F0PI*W0(L)*(G4 *(G1(L)+1./UBAR0) +G2(L)*G3(L) )/DENOM |
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| 285 | AP = F0PI*W0(L)*(G3(L)*(G1(L)-1./UBAR0) +G2(L)*G4 )/DENOM |
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| 286 | |
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| 287 | C CPMID AND CMMID ARE THE CPLUS AND CMINUS TERMS EVALUATED |
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| 288 | C AT THE MIDDLE OF THE LAYER. |
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| 289 | |
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| 290 | TAUMID = MIN(TAUCUM(L_LEVELS),TAUMAX) |
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| 291 | CPMID = AP*EXP(-MIN(TAUMID,TAUMAX)/UBAR0) |
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| 292 | CMMID = AM*EXP(-MIN(TAUMID,TAUMAX)/UBAR0) |
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| 293 | |
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| 294 | |
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| 295 | FMIDP(L) = XK1(L)*EP + GAMA(L)*XK2(L)*EM + CPMID |
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| 296 | FMIDM(L) = XK1(L)*EP*GAMA(L) + XK2(L)*EM + CMMID |
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| 297 | |
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| 298 | C Save the diffuse downward flux for TEMPGR calculations |
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| 299 | |
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| 300 | DIFFV = FMIDM(L) |
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| 301 | |
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| 302 | |
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| 303 | C ADD THE DIRECT FLUX TO THE DOWNWELLING TERM |
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| 304 | |
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| 305 | FMIDM(L)= FMIDM(L)+UBAR0*F0PI*EXP(-MIN(TAUMID,TAUMAX)/UBAR0) |
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| 306 | |
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| 307 | |
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| 308 | |
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| 309 | |
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| 310 | RETURN |
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| 311 | |
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| 312 | |
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| 313 | END |
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