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SUBROUTINE lwttm(pga, pgb, puu1, puu2, ptt) |
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USE dimens_m |
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USE dimphy |
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USE raddim |
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USE raddimlw |
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IMPLICIT NONE |
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|
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! ------------------------------------------------------------------ |
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! PURPOSE. |
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! -------- |
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! THIS ROUTINE COMPUTES THE TRANSMISSION FUNCTIONS FOR ALL THE |
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! ABSORBERS (H2O, UNIFORMLY MIXED GASES, AND O3) IN ALL SIX SPECTRAL |
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! INTERVALS. |
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|
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! METHOD. |
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! ------- |
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|
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! 1. TRANSMISSION FUNCTION BY H2O AND UNIFORMLY MIXED GASES ARE |
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! COMPUTED USING PADE APPROXIMANTS AND HORNER'S ALGORITHM. |
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! 2. TRANSMISSION BY O3 IS EVALUATED WITH MALKMUS'S BAND MODEL. |
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! 3. TRANSMISSION BY H2O CONTINUUM AND AEROSOLS FOLLOW AN |
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! A SIMPLE EXPONENTIAL DECREASE WITH ABSORBER AMOUNT. |
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|
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! REFERENCE. |
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! ---------- |
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|
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! SEE RADIATION'S PART OF THE MODEL'S DOCUMENTATION AND |
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! ECMWF RESEARCH DEPARTMENT DOCUMENTATION OF THE IFS |
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|
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! AUTHOR. |
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! ------- |
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! JEAN-JACQUES MORCRETTE *ECMWF* |
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|
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! MODIFICATIONS. |
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! -------------- |
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! ORIGINAL : 88-12-15 |
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|
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! ----------------------------------------------------------------------- |
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DOUBLE PRECISION o1h, o2h |
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PARAMETER (o1h=2230.) |
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PARAMETER (o2h=100.) |
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DOUBLE PRECISION rpialf0 |
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PARAMETER (rpialf0=2.0) |
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|
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! * ARGUMENTS: |
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|
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DOUBLE PRECISION pga(kdlon, 8, 2) ! PADE APPROXIMANTS |
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DOUBLE PRECISION pgb(kdlon, 8, 2) ! PADE APPROXIMANTS |
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DOUBLE PRECISION puu1(kdlon, nua) ! ABSORBER AMOUNTS FROM TOP TO LEVEL 1 |
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DOUBLE PRECISION puu2(kdlon, nua) ! ABSORBER AMOUNTS FROM TOP TO LEVEL 2 |
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DOUBLE PRECISION ptt(kdlon, ntra) ! TRANSMISSION FUNCTIONS |
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|
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! * LOCAL VARIABLES: |
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|
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INTEGER ja, jl |
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DOUBLE PRECISION zz, zxd, zxn |
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DOUBLE PRECISION zpu, zpu10, zpu11, zpu12, zpu13 |
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DOUBLE PRECISION zeu, zeu10, zeu11, zeu12, zeu13 |
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DOUBLE PRECISION zx, zy, zuxy, zsq1, zsq2, zvxy, zaercn, zto1 |
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DOUBLE PRECISION zto2 |
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DOUBLE PRECISION zxch4, zych4, zsqh41, zodh41 |
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DOUBLE PRECISION zxn2o, zyn2o, zsqn21, zodn21, zsqh42, zodh42 |
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DOUBLE PRECISION zsqn22, zodn22, za11, zttf11, za12, zttf12 |
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DOUBLE PRECISION zuu11, zuu12 |
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! ------------------------------------------------------------------ |
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|
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! * 1. HORNER'S ALGORITHM FOR H2O AND CO2 TRANSMISSION |
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! ----------------------------------------------- |
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|
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|
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|
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DO ja = 1, 8 |
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DO jl = 1, kdlon |
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zz = sqrt(puu1(jl,ja)-puu2(jl,ja)) |
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zxd = pgb(jl, ja, 1) + zz*(pgb(jl,ja,2)+zz) |
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zxn = pga(jl, ja, 1) + zz*(pga(jl,ja,2)) |
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ptt(jl, ja) = zxn/zxd |
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END DO |
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END DO |
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|
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! ------------------------------------------------------------------ |
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|
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! * 2. CONTINUUM, OZONE AND AEROSOL TRANSMISSION FUNCTIONS |
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! --------------------------------------------------- |
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|
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|
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DO jl = 1, kdlon |
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ptt(jl, 9) = ptt(jl, 8) |
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|
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! - CONTINUUM ABSORPTION: E- AND P-TYPE |
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|
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zpu = 0.002*(puu1(jl,10)-puu2(jl,10)) |
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zpu10 = 112.*zpu |
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zpu11 = 6.25*zpu |
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zpu12 = 5.00*zpu |
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zpu13 = 80.0*zpu |
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zeu = (puu1(jl,11)-puu2(jl,11)) |
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zeu10 = 12.*zeu |
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zeu11 = 6.25*zeu |
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zeu12 = 5.00*zeu |
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zeu13 = 80.0*zeu |
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|
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! - OZONE ABSORPTION |
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|
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zx = (puu1(jl,12)-puu2(jl,12)) |
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zy = (puu1(jl,13)-puu2(jl,13)) |
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zuxy = 4.*zx*zx/(rpialf0*zy) |
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zsq1 = sqrt(1.+o1h*zuxy) - 1. |
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zsq2 = sqrt(1.+o2h*zuxy) - 1. |
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zvxy = rpialf0*zy/(2.*zx) |
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zaercn = (puu1(jl,17)-puu2(jl,17)) + zeu12 + zpu12 |
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zto1 = exp(-zvxy*zsq1-zaercn) |
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zto2 = exp(-zvxy*zsq2-zaercn) |
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|
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! -- TRACE GASES (CH4, N2O, CFC-11, CFC-12) |
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|
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! * CH4 IN INTERVAL 800-970 + 1110-1250 CM-1 |
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|
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zxch4 = (puu1(jl,19)-puu2(jl,19)) |
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zych4 = (puu1(jl,20)-puu2(jl,20)) |
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zuxy = 4.*zxch4*zxch4/(0.103*zych4) |
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zsqh41 = sqrt(1.+33.7*zuxy) - 1. |
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zvxy = 0.103*zych4/(2.*zxch4) |
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zodh41 = zvxy*zsqh41 |
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|
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! * N2O IN INTERVAL 800-970 + 1110-1250 CM-1 |
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|
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zxn2o = (puu1(jl,21)-puu2(jl,21)) |
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zyn2o = (puu1(jl,22)-puu2(jl,22)) |
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zuxy = 4.*zxn2o*zxn2o/(0.416*zyn2o) |
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zsqn21 = sqrt(1.+21.3*zuxy) - 1. |
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zvxy = 0.416*zyn2o/(2.*zxn2o) |
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zodn21 = zvxy*zsqn21 |
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|
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! * CH4 IN INTERVAL 1250-1450 + 1880-2820 CM-1 |
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|
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zuxy = 4.*zxch4*zxch4/(0.113*zych4) |
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zsqh42 = sqrt(1.+400.*zuxy) - 1. |
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zvxy = 0.113*zych4/(2.*zxch4) |
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zodh42 = zvxy*zsqh42 |
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|
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! * N2O IN INTERVAL 1250-1450 + 1880-2820 CM-1 |
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|
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zuxy = 4.*zxn2o*zxn2o/(0.197*zyn2o) |
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zsqn22 = sqrt(1.+2000.*zuxy) - 1. |
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zvxy = 0.197*zyn2o/(2.*zxn2o) |
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zodn22 = zvxy*zsqn22 |
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|
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! * CFC-11 IN INTERVAL 800-970 + 1110-1250 CM-1 |
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|
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za11 = (puu1(jl,23)-puu2(jl,23))*4.404E+05 |
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zttf11 = 1. - za11*0.003225 |
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|
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! * CFC-12 IN INTERVAL 800-970 + 1110-1250 CM-1 |
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|
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za12 = (puu1(jl,24)-puu2(jl,24))*6.7435E+05 |
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zttf12 = 1. - za12*0.003225 |
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|
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zuu11 = -(puu1(jl,15)-puu2(jl,15)) - zeu10 - zpu10 |
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zuu12 = -(puu1(jl,16)-puu2(jl,16)) - zeu11 - zpu11 - zodh41 - zodn21 |
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ptt(jl, 10) = exp(-(puu1(jl,14)-puu2(jl,14))) |
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ptt(jl, 11) = exp(zuu11) |
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ptt(jl, 12) = exp(zuu12)*zttf11*zttf12 |
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ptt(jl, 13) = 0.7554*zto1 + 0.2446*zto2 |
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ptt(jl, 14) = ptt(jl, 10)*exp(-zeu13-zpu13) |
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ptt(jl, 15) = exp(-(puu1(jl,14)-puu2(jl,14))-zodh42-zodn22) |
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END DO |
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|
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RETURN |
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END SUBROUTINE lwttm |
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