| 1 | SUBROUTINE SWTT ( KIDIA, KFDIA, KLON, KNU, KA , PU, PTR) |
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| 2 | |
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| 3 | !**** *SWTT* - COMPUTES THE SHORTWAVE TRANSMISSION FUNCTIONS |
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| 4 | |
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| 5 | ! PURPOSE. |
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| 6 | ! -------- |
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| 7 | ! THIS ROUTINE COMPUTES THE TRANSMISSION FUNCTIONS FOR ALL THE |
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| 8 | ! ABSORBERS (H2O, UNIFORMLY MIXED GASES, AND O3) IN THE TWO SPECTRAL |
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| 9 | ! INTERVALS. |
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| 10 | |
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| 11 | !** INTERFACE. |
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| 12 | ! ---------- |
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| 13 | ! *SWTT* IS CALLED FROM *SW1S*, *SWNI*. |
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| 14 | |
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| 15 | |
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| 16 | ! EXPLICIT ARGUMENTS : |
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| 17 | ! -------------------- |
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| 18 | ! KNU : ; INDEX OF THE SPECTRAL INTERVAL |
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| 19 | ! KA : ; INDEX OF THE ABSORBER |
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| 20 | ! PU : (KLON) ; ABSORBER AMOUNT |
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| 21 | ! ==== OUTPUTS === |
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| 22 | ! PTR : (KLON) ; TRANSMISSION FUNCTION |
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| 23 | |
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| 24 | ! IMPLICIT ARGUMENTS : NONE |
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| 25 | ! -------------------- |
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| 26 | |
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| 27 | ! METHOD. |
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| 28 | ! ------- |
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| 29 | |
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| 30 | ! TRANSMISSION FUNCTION ARE COMPUTED USING PADE APPROXIMANTS |
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| 31 | ! AND HORNER'S ALGORITHM. |
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| 32 | |
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| 33 | ! EXTERNALS. |
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| 34 | ! ---------- |
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| 35 | |
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| 36 | ! NONE |
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| 37 | |
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| 38 | ! REFERENCE. |
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| 39 | ! ---------- |
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| 40 | |
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| 41 | ! SEE RADIATION'S PART OF THE MODEL'S DOCUMENTATION AND |
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| 42 | ! ECMWF RESEARCH DEPARTMENT DOCUMENTATION OF THE IFS |
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| 43 | |
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| 44 | ! AUTHOR. |
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| 45 | ! ------- |
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| 46 | ! JEAN-JACQUES MORCRETTE *ECMWF* |
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| 47 | |
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| 48 | ! MODIFICATIONS. |
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| 49 | ! -------------- |
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| 50 | ! ORIGINAL : 88-12-15 |
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| 51 | |
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| 52 | !----------------------------------------------------------------------- |
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| 53 | |
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| 54 | #include "tsmbkind.h" |
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| 55 | |
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| 56 | USE YOESW , ONLY : APAD ,BPAD ,D |
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| 57 | |
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| 58 | |
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| 59 | IMPLICIT NONE |
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| 60 | |
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| 61 | |
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| 62 | ! DUMMY INTEGER SCALARS |
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| 63 | INTEGER_M :: KA |
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| 64 | INTEGER_M :: KFDIA |
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| 65 | INTEGER_M :: KIDIA |
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| 66 | INTEGER_M :: KLON |
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| 67 | INTEGER_M :: KNU |
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| 68 | |
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| 69 | |
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| 70 | |
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| 71 | !----------------------------------------------------------------------- |
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| 72 | |
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| 73 | !* 0.1 ARGUMENTS |
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| 74 | ! --------- |
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| 75 | |
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| 76 | REAL_B :: PU(KLON), PTR(KLON) |
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| 77 | |
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| 78 | !----------------------------------------------------------------------- |
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| 79 | |
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| 80 | !* 0.2 LOCAL ARRAYS |
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| 81 | ! ------------ |
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| 82 | |
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| 83 | REAL_B :: ZR1(KLON), ZR2(KLON) |
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| 84 | |
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| 85 | ! LOCAL INTEGER SCALARS |
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| 86 | INTEGER_M :: JL |
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| 87 | |
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| 88 | |
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| 89 | !----------------------------------------------------------------------- |
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| 90 | |
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| 91 | !* 1. HORNER'S ALGORITHM TO COMPUTE TRANSMISSION FUNCTION |
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| 92 | |
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| 93 | |
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| 94 | DO JL = KIDIA,KFDIA |
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| 95 | ZR1(JL) = APAD(KNU,KA,1) + PU(JL) * (APAD(KNU,KA,2) + PU(JL)& |
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| 96 | &* ( APAD(KNU,KA,3) + PU(JL) * (APAD(KNU,KA,4) + PU(JL)& |
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| 97 | &* ( APAD(KNU,KA,5) + PU(JL) * (APAD(KNU,KA,6) + PU(JL)& |
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| 98 | &* ( APAD(KNU,KA,7) )))))) |
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| 99 | |
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| 100 | ZR2(JL) = BPAD(KNU,KA,1) + PU(JL) * (BPAD(KNU,KA,2) + PU(JL)& |
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| 101 | &* ( BPAD(KNU,KA,3) + PU(JL) * (BPAD(KNU,KA,4) + PU(JL)& |
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| 102 | &* ( BPAD(KNU,KA,5) + PU(JL) * (BPAD(KNU,KA,6) + PU(JL)& |
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| 103 | &* ( BPAD(KNU,KA,7) )))))) |
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| 104 | |
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| 105 | |
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| 106 | !* 2. ADD THE BACKGROUND TRANSMISSION |
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| 107 | |
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| 108 | |
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| 109 | |
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| 110 | PTR(JL) = (ZR1(JL) / ZR2(JL)) * (_ONE_ - D(KNU,KA)) + D(KNU,KA) |
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| 111 | ENDDO |
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| 112 | |
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| 113 | RETURN |
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| 114 | END SUBROUTINE SWTT |
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