[4728] | 1 | SUBROUTINE LIQUID_EFFECTIVE_RADIUS & |
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| 2 | & (YDERAD,KIDIA, KFDIA, KLON, KLEV, & |
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| 3 | & PPRESSURE, PTEMPERATURE, PCLOUD_FRAC, PQ_LIQ, PQ_RAIN, & |
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| 4 | & PLAND_FRAC, PCCN_LAND, PCCN_SEA, & |
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| 5 | & PRE_UM) !, PPERT) |
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| 6 | |
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| 7 | ! LIQUID_EFFECTIVE_RADIUS |
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| 8 | ! |
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| 9 | ! (C) Copyright 2015- ECMWF. |
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| 10 | ! |
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| 11 | ! This software is licensed under the terms of the Apache Licence Version 2.0 |
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| 12 | ! which can be obtained at http://www.apache.org/licenses/LICENSE-2.0. |
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| 13 | ! |
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| 14 | ! In applying this licence, ECMWF does not waive the privileges and immunities |
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| 15 | ! granted to it by virtue of its status as an intergovernmental organisation |
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| 16 | ! nor does it submit to any jurisdiction. |
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| 17 | ! |
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| 18 | ! PURPOSE |
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| 19 | ! ------- |
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| 20 | ! Calculate effective radius of liquid clouds |
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| 21 | ! |
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| 22 | ! AUTHOR |
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| 23 | ! ------ |
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| 24 | ! Robin Hogan, ECMWF (using code extracted from radlswr.F90) |
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| 25 | ! Original: 2015-09-24 |
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| 26 | ! |
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| 27 | ! MODIFICATIONS |
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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 | |
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| 33 | USE PARKIND1 , ONLY : JPIM, JPRB |
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| 34 | USE YOMHOOK , ONLY : LHOOK, DR_HOOK, JPHOOK |
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| 35 | USE YOERAD , ONLY : TERAD |
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| 36 | USE YOERDU , ONLY : REPLOG, REPSCW |
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| 37 | USE YOMLUN , ONLY : NULERR |
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| 38 | USE YOMCST , ONLY : RD, RPI |
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| 39 | |
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| 40 | ! ------------------------------------------------------------------- |
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| 41 | |
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| 42 | IMPLICIT NONE |
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| 43 | |
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| 44 | ! INPUT ARGUMENTS |
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| 45 | |
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| 46 | ! *** Array dimensions and ranges |
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| 47 | TYPE(TERAD) ,INTENT(IN) :: YDERAD |
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| 48 | INTEGER(KIND=JPIM),INTENT(IN) :: KIDIA ! Start column to process |
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| 49 | INTEGER(KIND=JPIM),INTENT(IN) :: KFDIA ! End column to process |
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| 50 | INTEGER(KIND=JPIM),INTENT(IN) :: KLON ! Number of columns |
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| 51 | INTEGER(KIND=JPIM),INTENT(IN) :: KLEV ! Number of levels |
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| 52 | |
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| 53 | ! *** Variables on model levels |
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| 54 | REAL(KIND=JPRB), INTENT(IN) :: PPRESSURE(KLON,KLEV) ! (Pa) |
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| 55 | REAL(KIND=JPRB), INTENT(IN) :: PTEMPERATURE(KLON,KLEV) ! (K) |
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| 56 | REAL(KIND=JPRB), INTENT(IN) :: PCLOUD_FRAC(KLON,KLEV) |
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| 57 | REAL(KIND=JPRB), INTENT(IN) :: PQ_LIQ(KLON,KLEV) ! (kg/kg) |
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| 58 | REAL(KIND=JPRB), INTENT(IN) :: PQ_RAIN(KLON,KLEV) ! (kg/kg) |
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| 59 | |
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| 60 | ! *** Single-level variables |
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| 61 | REAL(KIND=JPRB), INTENT(IN) :: PLAND_FRAC(KLON) ! 1=land, 0=sea |
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| 62 | REAL(KIND=JPRB), INTENT(IN) :: PCCN_LAND(KLON) |
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| 63 | REAL(KIND=JPRB), INTENT(IN) :: PCCN_SEA(KLON) |
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| 64 | |
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| 65 | ! OUTPUT ARGUMENT |
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| 66 | ! Effective radius |
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| 67 | REAL(KIND=JPRB), INTENT(OUT) :: PRE_UM(KLON,KLEV) ! (microns) |
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| 68 | |
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| 69 | ! PARAMETERS |
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| 70 | |
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| 71 | ! Minimum and maximum effective radius, in microns |
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| 72 | REAL(KIND=JPRB), PARAMETER :: PP_MIN_RE_UM = 4.0_JPRB |
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| 73 | REAL(KIND=JPRB), PARAMETER :: PP_MAX_RE_UM = 30.0_JPRB |
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| 74 | |
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| 75 | ! LOCAL VARIABLES |
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| 76 | INTEGER(KIND=JPIM) :: IRADLP ! ID of effective radius scheme to use |
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| 77 | REAL(KIND=JPRB) :: ZCCN ! CCN concentration (units?) |
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| 78 | |
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| 79 | REAL(KIND=JPRB) :: ZSPECTRAL_DISPERSION |
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| 80 | REAL(KIND=JPRB) :: ZNTOT_CM3 ! Number conc in cm-3 |
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| 81 | REAL(KIND=JPRB) :: ZRE_CUBED |
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| 82 | REAL(KIND=JPRB) :: ZLWC_GM3, ZRWC_GM3 ! In-cloud liquid, rain content in g m-3 |
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| 83 | REAL(KIND=JPRB) :: ZAIR_DENSITY_GM3 ! Air density in g m-3 |
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| 84 | REAL(KIND=JPRB) :: ZRAIN_RATIO ! Ratio of rain to liquid water content |
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| 85 | REAL(KIND=JPRB) :: ZWOOD_FACTOR, ZRATIO |
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| 86 | |
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| 87 | INTEGER(KIND=JPIM) :: JL, JK |
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| 88 | |
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| 89 | REAL(KIND=JPHOOK) :: ZHOOK_HANDLE |
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| 90 | |
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| 91 | ! ------------------------------------------------------------------- |
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| 92 | |
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| 93 | #include "abor1.intfb.h" |
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| 94 | |
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| 95 | ! ------------------------------------------------------------------- |
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| 96 | |
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| 97 | IF (LHOOK) CALL DR_HOOK('LIQUID_EFFECTIVE_RADIUS',0,ZHOOK_HANDLE) |
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| 98 | |
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| 99 | ! ------------------------------------------------------------------- |
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| 100 | |
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| 101 | IRADLP=YDERAD%NRADLP |
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| 102 | |
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| 103 | SELECT CASE(IRADLP) |
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| 104 | CASE(0) |
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| 105 | ! Very old parameterization as a function of pressure, used in ERA-15 |
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| 106 | PRE_UM(KIDIA:KFDIA,:) = 10.0_JPRB& |
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| 107 | & + (100000.0_JPRB-PPRESSURE(KIDIA:KFDIA,:))*3.5_JPRB |
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| 108 | |
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| 109 | CASE(1) |
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| 110 | ! Simple distinction between land (10um) and ocean (13um) by Zhang |
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| 111 | ! and Rossow |
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| 112 | DO JL = KIDIA,KFDIA |
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| 113 | IF (PLAND_FRAC(JL) < 0.5_JPRB) THEN |
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| 114 | PRE_UM(JL,:) = 13.0_JPRB |
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| 115 | ELSE |
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| 116 | PRE_UM(JL,:) = 10.0_JPRB |
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| 117 | ENDIF |
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| 118 | ENDDO |
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| 119 | |
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| 120 | CASE(2) |
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| 121 | ! Martin et al. (JAS 1994) |
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| 122 | DO JL = KIDIA,KFDIA |
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| 123 | ! First compute the cloud droplet concentration |
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| 124 | IF (PLAND_FRAC(JL) < 0.5_JPRB) THEN |
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| 125 | ! Sea case |
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| 126 | IF (YDERAD%LCCNO) THEN |
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| 127 | ZCCN = PCCN_SEA(JL) |
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| 128 | ELSE |
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| 129 | ZCCN = YDERAD%RCCNSEA |
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| 130 | ENDIF |
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| 131 | ZSPECTRAL_DISPERSION = 0.77_JPRB |
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| 132 | ! Cloud droplet concentration in cm-3 (activated CCN) over |
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| 133 | ! ocean |
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| 134 | ZNTOT_CM3 = -1.15E-03_JPRB*ZCCN*ZCCN + 0.963_JPRB*ZCCN + 5.30_JPRB |
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| 135 | ELSE |
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| 136 | ! Land case |
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| 137 | IF (YDERAD%LCCNL) THEN |
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| 138 | ZCCN=PCCN_LAND(JL) |
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| 139 | ELSE |
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| 140 | ZCCN=YDERAD%RCCNLND |
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| 141 | ENDIF |
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| 142 | ZSPECTRAL_DISPERSION = 0.69_JPRB |
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| 143 | ! Cloud droplet concentration in cm-3 (activated CCN) over |
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| 144 | ! land |
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| 145 | ZNTOT_CM3 = -2.10E-04_JPRB*ZCCN*ZCCN + 0.568_JPRB*ZCCN - 27.9_JPRB |
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| 146 | ENDIF |
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| 147 | |
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| 148 | ZRATIO = (0.222_JPRB/ZSPECTRAL_DISPERSION)**0.333_JPRB |
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| 149 | |
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| 150 | DO JK = 1,KLEV |
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| 151 | |
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| 152 | ! Only consider cloudy regions |
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| 153 | IF (PCLOUD_FRAC(JL,JK) >= 0.001_JPRB& |
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| 154 | & .AND. (PQ_LIQ(JL,JK)+PQ_RAIN(JL,JK)) > 0.0_JPRB) THEN |
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| 155 | |
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| 156 | ! Compute liquid and rain water contents |
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| 157 | ZAIR_DENSITY_GM3 = 1000.0_JPRB * PPRESSURE(JL,JK)& |
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| 158 | & / (RD*PTEMPERATURE(JL,JK)) |
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| 159 | ! In-cloud mean water contents found by dividing by cloud |
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| 160 | ! fraction |
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| 161 | ZLWC_GM3 = ZAIR_DENSITY_GM3 * PQ_LIQ(JL,JK) / PCLOUD_FRAC(JL,JK) |
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| 162 | ZRWC_GM3 = ZAIR_DENSITY_GM3 * PQ_RAIN(JL,JK) / PCLOUD_FRAC(JL,JK) |
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| 163 | |
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| 164 | ! Wood's (2000, eq. 19) adjustment to Martin et al's |
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| 165 | ! parameterization |
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| 166 | IF (ZLWC_GM3 > REPSCW) THEN |
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| 167 | ZRAIN_RATIO = ZRWC_GM3 / ZLWC_GM3 |
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| 168 | ZWOOD_FACTOR = ((1.0_JPRB + ZRAIN_RATIO)**0.666_JPRB)& |
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| 169 | & / (1.0_JPRB + 0.2_JPRB * ZRATIO*ZRAIN_RATIO) |
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| 170 | ELSE |
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| 171 | ZWOOD_FACTOR = 1.0_JPRB |
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| 172 | ENDIF |
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| 173 | |
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| 174 | ! g m-3 and cm-3 units cancel out with density of water |
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| 175 | ! 10^6/(1000*1000); need a factor of 10^6 to convert to |
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| 176 | ! microns and cubed root is factor of 100 which appears in |
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| 177 | ! equation below |
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| 178 | ZRE_CUBED = (3.0_JPRB * (ZLWC_GM3 + ZRWC_GM3))& |
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| 179 | & / (4.0_JPRB*RPI*ZNTOT_CM3*ZSPECTRAL_DISPERSION) |
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| 180 | IF (ZRE_CUBED > REPLOG) THEN |
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| 181 | PRE_UM(JL,JK) = ZWOOD_FACTOR*100.0_JPRB*EXP(0.333_JPRB*LOG(ZRE_CUBED)) |
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| 182 | ! Make sure effective radius is bounded in range 4-30 microns |
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| 183 | PRE_UM(JL,JK) = MAX(PP_MIN_RE_UM, MIN(PRE_UM(JL,JK), PP_MAX_RE_UM)) |
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| 184 | ELSE |
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| 185 | PRE_UM(JL,JK) = PP_MIN_RE_UM |
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| 186 | ENDIF |
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| 187 | |
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| 188 | ELSE |
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| 189 | ! Cloud fraction or liquid+rain water content too low to |
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| 190 | ! consider this a cloud |
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| 191 | PRE_UM(JL,JK) = PP_MIN_RE_UM |
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| 192 | |
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| 193 | ENDIF |
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| 194 | |
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| 195 | ENDDO |
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| 196 | |
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| 197 | ENDDO |
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| 198 | |
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| 199 | CASE DEFAULT |
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| 200 | WRITE(NULERR,'(A,I0,A)') 'LIQUID EFFECTIVE RADIUS OPTION IRADLP=',IRADLP,' NOT AVAILABLE' |
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| 201 | CALL ABOR1('ERROR IN LIQUID_EFFECTIVE_RADIUS') |
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| 202 | END SELECT |
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| 203 | |
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| 204 | ! ------------------------------------------------------------------- |
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| 205 | |
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| 206 | IF (LHOOK) CALL DR_HOOK('LIQUID_EFFECTIVE_RADIUS',1,ZHOOK_HANDLE) |
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| 207 | |
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| 208 | END SUBROUTINE LIQUID_EFFECTIVE_RADIUS |
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