[4728] | 1 | SUBROUTINE ICE_EFFECTIVE_RADIUS & |
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| 2 | & (YDERAD,KIDIA, KFDIA, KLON, KLEV, & |
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| 3 | & PPRESSURE, PTEMPERATURE, PCLOUD_FRAC, PQ_ICE, PQ_SNOW, PGEMU, & |
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| 4 | & PRE_UM) !, PPERT) |
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| 5 | |
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| 6 | ! ICE_EFFECTIVE_RADIUS |
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| 7 | ! |
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| 8 | ! (C) Copyright 2016- ECMWF. |
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| 9 | ! |
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| 10 | ! This software is licensed under the terms of the Apache Licence Version 2.0 |
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| 11 | ! which can be obtained at http://www.apache.org/licenses/LICENSE-2.0. |
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| 12 | ! |
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| 13 | ! In applying this licence, ECMWF does not waive the privileges and immunities |
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| 14 | ! granted to it by virtue of its status as an intergovernmental organisation |
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| 15 | ! nor does it submit to any jurisdiction. |
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| 16 | ! |
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| 17 | ! PURPOSE |
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| 18 | ! ------- |
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| 19 | ! Calculate effective radius of ice clouds |
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| 20 | ! |
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| 21 | ! AUTHOR |
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| 22 | ! ------ |
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| 23 | ! Robin Hogan, ECMWF (using code extracted from radlswr.F90) |
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| 24 | ! Original: 2016-02-24 |
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| 25 | ! |
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| 26 | ! MODIFICATIONS |
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| 27 | ! ------------- |
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| 28 | ! |
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| 29 | ! |
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| 30 | ! ------------------------------------------------------------------- |
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| 31 | |
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| 32 | USE PARKIND1 , ONLY : JPIM, JPRB |
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| 33 | USE YOMHOOK , ONLY : LHOOK, DR_HOOK, JPHOOK |
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| 34 | USE YOERAD , ONLY : TERAD |
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| 35 | USE YOMLUN , ONLY : NULERR |
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| 36 | USE YOMCST , ONLY : RD, RTT |
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| 37 | |
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| 38 | ! ------------------------------------------------------------------- |
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| 39 | |
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| 40 | IMPLICIT NONE |
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| 41 | |
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| 42 | ! INPUT ARGUMENTS |
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| 43 | |
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| 44 | ! *** Array dimensions and ranges |
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| 45 | TYPE(TERAD) ,INTENT(IN) :: YDERAD |
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| 46 | INTEGER(KIND=JPIM),INTENT(IN) :: KIDIA ! Start column to process |
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| 47 | INTEGER(KIND=JPIM),INTENT(IN) :: KFDIA ! End column to process |
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| 48 | INTEGER(KIND=JPIM),INTENT(IN) :: KLON ! Number of columns |
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| 49 | INTEGER(KIND=JPIM),INTENT(IN) :: KLEV ! Number of levels |
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| 50 | |
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| 51 | ! *** Variables on model levels |
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| 52 | REAL(KIND=JPRB), INTENT(IN) :: PPRESSURE(KLON,KLEV) ! (Pa) |
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| 53 | REAL(KIND=JPRB), INTENT(IN) :: PTEMPERATURE(KLON,KLEV) ! (K) |
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| 54 | REAL(KIND=JPRB), INTENT(IN) :: PCLOUD_FRAC(KLON,KLEV) ! (kg/kg) |
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| 55 | REAL(KIND=JPRB), INTENT(IN) :: PQ_ICE(KLON,KLEV) ! (kg/kg) |
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| 56 | REAL(KIND=JPRB), INTENT(IN) :: PQ_SNOW(KLON,KLEV) ! (kg/kg) |
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| 57 | |
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| 58 | ! *** Single level variable |
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| 59 | REAL(KIND=JPRB), INTENT(IN) :: PGEMU(KLON) ! Sine of latitude |
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| 60 | |
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| 61 | ! OUTPUT ARGUMENT |
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| 62 | ! Effective radius |
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| 63 | REAL(KIND=JPRB), INTENT(OUT) :: PRE_UM(KLON,KLEV) ! (microns) |
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| 64 | |
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| 65 | ! OPTIONAL INPUT ARGUMENT |
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| 66 | ! SPP perturbation pattern |
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| 67 | ! REAL(KIND=JPRB), INTENT(IN), OPTIONAL :: PPERT(KLON,YSPP%N2DRAD) |
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| 68 | |
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| 69 | ! LOCAL VARIABLES |
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| 70 | |
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| 71 | REAL(KIND=JPRB) :: ZIWC_INCLOUD_GM3 ! In-cloud ice+snow water content in g m-3 |
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| 72 | REAL(KIND=JPRB) :: ZAIR_DENSITY_GM3 ! Air density in g m-3 |
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| 73 | |
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| 74 | REAL(KIND=JPRB) :: ZTEMPERATURE_C ! Temperature, degrees Celcius |
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| 75 | REAL(KIND=JPRB) :: ZAIWC, ZBIWC ! Factors in empirical relationship |
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| 76 | REAL(KIND=JPRB) :: ZDEFAULT_RE_UM ! Default effective radius in microns |
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| 77 | REAL(KIND=JPRB) :: ZDIAMETER_UM ! Effective diameter in microns |
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| 78 | |
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| 79 | ! Min effective diameter in microns; may vary with latitude |
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| 80 | REAL(KIND=JPRB) :: ZMIN_DIAMETER_UM(KLON) |
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| 81 | |
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| 82 | INTEGER(KIND=JPIM) :: JL, JK |
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| 83 | |
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| 84 | REAL(KIND=JPHOOK) :: ZHOOK_HANDLE |
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| 85 | |
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| 86 | ! ------------------------------------------------------------------- |
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| 87 | |
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| 88 | #include "abor1.intfb.h" |
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| 89 | |
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| 90 | ! ------------------------------------------------------------------- |
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| 91 | |
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| 92 | IF (LHOOK) CALL DR_HOOK('ICE_EFFECTIVE_RADIUS',0,ZHOOK_HANDLE) |
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| 93 | |
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| 94 | ! ------------------------------------------------------------------- |
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| 95 | |
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| 96 | SELECT CASE(YDERAD%NRADIP) |
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| 97 | CASE(0) |
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| 98 | ! Ice effective radius fixed at 40 microns |
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| 99 | PRE_UM(KIDIA:KFDIA,:) = 40.0_JPRB |
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| 100 | |
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| 101 | CASE(1,2) |
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| 102 | ! Ice effective radius from Liou and Ou (1994) |
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| 103 | DO JK = 1,KLEV |
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| 104 | DO JL = KIDIA,KFDIA |
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| 105 | ! Convert Kelvin to Celcius, preventing positive numbers |
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| 106 | ZTEMPERATURE_C = MIN(PTEMPERATURE(JL,JK) - RTT, -0.1_JPRB) |
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| 107 | ! Liou and Ou's empirical formula |
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| 108 | PRE_UM(JL,JK) = 326.3_JPRB + ZTEMPERATURE_C * (12.42_JPRB& |
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| 109 | & + ZTEMPERATURE_C * (0.197_JPRB + ZTEMPERATURE_C * 0.0012_JPRB)) |
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| 110 | IF (YDERAD%NRADIP == 1) THEN |
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| 111 | ! Original Liou and Ou (1994) bounds of 40-130 microns |
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| 112 | PRE_UM(JL,JK) = MAX(PRE_UM(JL,JK), 40.0_JPRB) |
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| 113 | PRE_UM(JL,JK) = MIN(PRE_UM(JL,JK),130.0_JPRB) |
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| 114 | ELSE |
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| 115 | ! Formulation following Jakob, Klein modifications to ice |
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| 116 | ! content |
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| 117 | PRE_UM(JL,JK) = MAX(PRE_UM(JL,JK), 30.0_JPRB) |
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| 118 | PRE_UM(JL,JK) = MIN(PRE_UM(JL,JK), 60.0_JPRB) |
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| 119 | ENDIF |
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| 120 | ENDDO |
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| 121 | ENDDO |
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| 122 | |
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| 123 | CASE(3) |
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| 124 | ! Ice effective radius = f(T,IWC) from Sun and Rikus (1999), revised |
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| 125 | ! by Sun (2001) |
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| 126 | |
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| 127 | ! Default effective radius is computed from an effective diameter of |
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| 128 | ! 80 microns; note that multiplying by re2de actually converts from |
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| 129 | ! effective diameter to effective radius. |
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| 130 | ZDEFAULT_RE_UM = 80.0_JPRB * YDERAD%RRE2DE |
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| 131 | |
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| 132 | ! Minimum effective diameter may vary with latitude |
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| 133 | IF (YDERAD%NMINICE == 0) THEN |
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| 134 | ! Constant effective diameter |
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| 135 | ZMIN_DIAMETER_UM(KIDIA:KFDIA) = YDERAD%RMINICE |
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| 136 | ELSE |
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| 137 | ! Ice effective radius varies with latitude, smaller at poles |
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| 138 | DO JL = KIDIA,KFDIA |
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| 139 | ZMIN_DIAMETER_UM(JL) = 20.0_JPRB + (YDERAD%RMINICE - 20.0_JPRB)& |
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| 140 | & * COS(ASIN(PGEMU(JL))) |
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| 141 | ENDDO |
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| 142 | ENDIF |
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| 143 | |
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| 144 | DO JK = 1,KLEV |
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| 145 | DO JL = KIDIA,KFDIA |
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| 146 | IF (PCLOUD_FRAC(JL,JK) > 0.001_JPRB& |
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| 147 | & .AND. (PQ_ICE(JL,JK)+PQ_SNOW(JL,JK)) > 0.0_JPRB) THEN |
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| 148 | ZAIR_DENSITY_GM3 = 1000.0_JPRB * PPRESSURE(JL,JK) / (RD*PTEMPERATURE(JL,JK)) |
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| 149 | ZIWC_INCLOUD_GM3 = ZAIR_DENSITY_GM3 * (PQ_ICE(JL,JK) + PQ_SNOW(JL,JK))& |
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| 150 | & / PCLOUD_FRAC(JL,JK) |
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| 151 | ZTEMPERATURE_C = PTEMPERATURE(JL,JK) - RTT |
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| 152 | ! Sun, 2001 (corrected from Sun & Rikus, 1999) |
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| 153 | ZAIWC = 45.8966_JPRB * ZIWC_INCLOUD_GM3**0.2214_JPRB |
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| 154 | ZBIWC = 0.7957_JPRB * ZIWC_INCLOUD_GM3**0.2535_JPRB |
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| 155 | ZDIAMETER_UM = (1.2351_JPRB + 0.0105_JPRB * ZTEMPERATURE_C)& |
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| 156 | & * (ZAIWC + ZBIWC*(PTEMPERATURE(JL,JK) - 83.15_JPRB)) |
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| 157 | |
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| 158 | ZDIAMETER_UM = MIN ( MAX( ZDIAMETER_UM, ZMIN_DIAMETER_UM(JL)), 155.0_JPRB) |
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| 159 | PRE_UM(JL,JK) = ZDIAMETER_UM * YDERAD%RRE2DE |
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| 160 | ELSE |
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| 161 | PRE_UM(JL,JK) = ZDEFAULT_RE_UM |
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| 162 | ENDIF |
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| 163 | ENDDO |
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| 164 | ENDDO |
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| 165 | |
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| 166 | CASE DEFAULT |
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| 167 | WRITE(NULERR,'(A,I0,A)') 'ICE EFFECTIVE RADIUS OPTION NRADLP=',YDERAD%NRADIP,' NOT AVAILABLE' |
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| 168 | CALL ABOR1('ERROR IN ICE_EFFECTIVE_RADIUS') |
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| 169 | |
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| 170 | END SELECT |
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| 171 | |
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| 172 | ! ------------------------------------------------------------------- |
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| 173 | |
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| 174 | IF (LHOOK) CALL DR_HOOK('ICE_EFFECTIVE_RADIUS',1,ZHOOK_HANDLE) |
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| 175 | |
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| 176 | END SUBROUTINE ICE_EFFECTIVE_RADIUS |
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