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SURFEX v7.3
General documentation of Surfex
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SURFEX v7.3
General documentation of Surfex
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00001 ! ######### 00002 SUBROUTINE HYDRO_VEG(HRAIN, PTSTEP, PMUF, PRR, PLEV, PLETR, & 00003 PVEG, PPSNV, PWR, PWRMAX, PPG, PDRIP, & 00004 PRRVEG ) 00005 ! ##################################################################### 00006 ! 00007 !!**** *HYDRO_VEG* 00008 !! 00009 !! PURPOSE 00010 !! ------- 00011 ! 00012 ! Calculates the evolution of the liquid water retained in the vegetation 00013 ! canopy (Wr). Also determine the runoff from the canopy that reaches the 00014 ! ground (Mahfouf et al. 1995). This routine take into account the spatially 00015 ! exponential distribution of precip introduced by Entekhabi and Eagleson (1989). 00016 ! 00017 ! 00018 !!** METHOD 00019 !! ------ 00020 ! 00021 !! EXTERNAL 00022 !! -------- 00023 !! 00024 !! none 00025 !! 00026 !! IMPLICIT ARGUMENTS 00027 !! ------------------ 00028 !! 00029 !! USE MODD_CST 00030 !! 00031 !! REFERENCE 00032 !! --------- 00033 !! 00034 !! Noilhan and Planton (1989) 00035 !! Belair (1995) 00036 !! Mahfouf et al. 1995 00037 !! Decharme and Douville (2006) 00038 !! 00039 !! AUTHOR 00040 !! ------ 00041 !! 00042 !! S. Belair * Meteo-France * 00043 !! 00044 !! MODIFICATIONS 00045 !! ------------- 00046 !! 00047 !! Original 14/03/95 00048 !! 31/08/98 (V. Masson and F. Habets) add Dumenil et Todini 00049 !! runoff scheme 00050 !! 31/08/98 (V. Masson and A. Boone) add the third soil-water 00051 !! reservoir (WG3,D3) 00052 !! 31/05/04 (B. Decharme) add the rainfall spatial distribution 00053 !! 2008 (B. Decharme) add the dripping rate as new diag 00054 !! 11/2009 (S.Senesi) returns precipitation intercepted by 00055 ! the vegetation 00056 !! 07/2011 (B. Decharme) delete SGH for very fine precipitation 00057 !! 09/2012 (B. Decharme) Computation efficiency for HRAIN=='SGH' 00058 !! 10/2012 (B. Decharme) PPG intent(out) 00059 ! 00060 !------------------------------------------------------------------------------- 00061 ! 00062 !* 0. DECLARATIONS 00063 ! ------------ 00064 ! 00065 USE MODD_CSTS,ONLY : XLVTT 00066 ! 00067 USE MODD_SGH_PAR, ONLY : X001 00068 ! 00069 USE YOMHOOK ,ONLY : LHOOK, DR_HOOK 00070 USE PARKIND1 ,ONLY : JPRB 00071 ! 00072 IMPLICIT NONE 00073 ! 00074 !* 0.1 declarations of arguments 00075 ! 00076 CHARACTER(LEN=*), INTENT(IN) :: HRAIN ! Rainfall spatial distribution 00077 ! 'DEF' = No rainfall spatial distribution 00078 ! 'SGH' = Rainfall exponential spatial distribution 00079 ! 00080 ! 00081 REAL, INTENT(IN) :: PTSTEP 00082 ! timestep of the integration 00083 ! 00084 REAL, DIMENSION(:), INTENT(IN) :: PRR, PLEV, PLETR, PMUF 00085 ! PRR = rain rate 00086 ! PLEV = latent heat of evaporation over vegetation 00087 ! PLETR = evapotranspiration of the vegetation 00088 ! PMUF = fraction of the grid cell reached by the precipitation 00089 ! 00090 REAL, DIMENSION(:), INTENT(IN) :: PVEG, PWRMAX 00091 ! PVEG = fraction of vegetation 00092 ! PWRMAX = maximum equivalent water content 00093 ! in the vegetation canopy 00094 ! 00095 REAL, DIMENSION(:), INTENT(IN) :: PPSNV 00096 ! PPSNV = vegetation covered by snow 00097 ! 00098 REAL, DIMENSION(:), INTENT(INOUT) :: PWR 00099 ! PWR = liquid water retained on the foliage 00100 ! of the vegetation at time 't+dt' 00101 ! 00102 REAL, DIMENSION(:), INTENT(OUT) :: PPG,PDRIP 00103 ! PPG = total water reaching the ground 00104 ! PDRIP = Dripping from the vegetation 00105 REAL, DIMENSION(:), INTENT(OUT) :: PRRVEG 00106 ! PRRVEG = Precip. intercepted by vegetation (kg/m2/s) 00107 ! 00108 ! 00109 !* 0.2 declarations of local variables 00110 ! 00111 REAL, DIMENSION(SIZE(PVEG)) :: ZER 00112 ! ZER = evaporation rate from the canopy 00113 ! 00114 REAL, DIMENSION(SIZE(PVEG)) :: ZWR ! for time stability scheme 00115 ! 00116 REAL, DIMENSION(SIZE(PVEG)) :: ZRUIR, ZRUIR2 ! dripping from the vegetation 00117 ! 00118 REAL :: ZLIM 00119 ! 00120 REAL(KIND=JPRB) :: ZHOOK_HANDLE 00121 ! 00122 !------------------------------------------------------------------------------- 00123 ! 00124 IF (LHOOK) CALL DR_HOOK('HYDRO_VEG',0,ZHOOK_HANDLE) 00125 ZRUIR (:) = 0. 00126 ZRUIR2(:) = 0. 00127 PDRIP (:) = 0. 00128 ZWR (:) = 0. 00129 ! 00130 !* 1. EVOLUTION OF THE EQUIVALENT WATER CONTENT Wr 00131 ! -------------------------------------------- 00132 ! 00133 !evaporation rates 00134 ! 00135 ZER(:) = (PLEV(:)-PLETR(:)) / XLVTT 00136 ! 00137 !intercepted rainfall rate 00138 ! 00139 PRRVEG(:) = PVEG(:) * (1.-PPSNV(:)) * PRR(:) 00140 ! 00141 !evolution of the intercepted water 00142 !(if we don't consider the runoff) 00143 ! 00144 PWR(:) = PWR(:) - PTSTEP * (ZER(:) - PRRVEG(:)) 00145 ! 00146 !When Wr < 0, the direct evaporation 00147 !(i.e., EV-ETR) removes too much 00148 !liquid water from the vegetation 00149 !reservoir. This is considered as 00150 !negative runoff, and it is stocked 00151 !in ZRUIR2. 00152 ! 00153 ZRUIR2(:) = MIN(0.,PWR(:)/PTSTEP) 00154 ! 00155 !Wr must be positive 00156 ! 00157 PWR(:) = MAX(0., PWR(:)) 00158 ! 00159 IF(HRAIN=='SGH')THEN 00160 ! 00161 !* 2. SPATIALLY EXPONENTIAL DISTRIBUTION OF PRECIPITATION 00162 ! --------------------------------------------------- 00163 ! 00164 ! 00165 ! Subgrid dripping from Wr 00166 ! 00167 ZLIM=X001/PTSTEP 00168 ! 00169 WHERE(PRRVEG(:)>ZLIM.AND.PWR(:)>0.0) 00170 ZRUIR(:) = PRRVEG(:)*EXP(PMUF(:)*(PWR(:)-PWRMAX(:))/(PRRVEG(:)*PTSTEP)) 00171 ZRUIR(:) = MIN(ZRUIR(:),PWR(:)/PTSTEP) 00172 ENDWHERE 00173 ! 00174 IF(PTSTEP>300.)THEN 00175 ! 00176 ! if the isba time step is coarser than 5min, the "prediction/correction" method is applied 00177 ! to Wr using the predicted Wr* at the end of the time step for time numerical stability 00178 ! 00179 ZWR(:) = PWR(:)-PTSTEP*ZRUIR(:) 00180 ZRUIR(:) = 0.0 00181 ! 00182 ! if the dripping is too big, the "prediction/correction" method is applied to Wr using 00183 ! the predicted Wr* at the midle of the time step for time numerical stability 00184 ! (<=> Runge-Kutta order 1 rang 1) 00185 ! 00186 WHERE(PRRVEG(:)>ZLIM.AND.ZWR(:)<=0.0) 00187 ZRUIR(:) = PRRVEG(:)*EXP(PMUF(:)*(PWR(:)-PWRMAX(:))/(PRRVEG(:)*PTSTEP/2.)) 00188 ZRUIR(:) = MIN(ZRUIR(:),PWR(:)/(PTSTEP/2.)) 00189 ZWR (:) = PWR(:)-PTSTEP*ZRUIR(:)/2. 00190 ZRUIR(:) = 0.0 00191 ENDWHERE 00192 ! 00193 ! Calculate the corrected dripping from the predicted Wr* 00194 ! 00195 WHERE(PRRVEG(:)>ZLIM.AND.ZWR(:)>0.0) 00196 ZRUIR(:) = PRRVEG(:)*EXP(PMUF(:)*(ZWR(:)-PWRMAX(:))/(PRRVEG(:)*PTSTEP)) 00197 ZRUIR(:) = MIN(ZRUIR(:),PWR(:)/PTSTEP) 00198 ENDWHERE 00199 ! 00200 ENDIF 00201 ! 00202 PWR(:) = PWR(:)-PTSTEP*ZRUIR(:) 00203 ! 00204 ! As previously Wr must be positive (numerical artefact) 00205 ! 00206 ZRUIR2(:) = ZRUIR2(:) + MIN(0.,PWR(:)/PTSTEP) 00207 PWR(:) = MAX( 0., PWR(:) ) 00208 ! 00209 ! Wr must be smaller then Wrmax 00210 ! Then if Wr remain > Wrmax, there is runoff 00211 ! 00212 ZRUIR(:) = ZRUIR(:) + MAX(0., (PWR(:) - PWRMAX(:)) / PTSTEP ) 00213 ! 00214 ELSE 00215 ! 00216 ! if Wr > Wrmax, there is runoff 00217 ! 00218 ZRUIR(:) = MAX(0., (PWR(:) - PWRMAX(:)) / PTSTEP ) 00219 ! 00220 ENDIF 00221 ! 00222 !Wr must be smaller then Wrmax 00223 ! 00224 PWR(:) = MIN(PWR(:), PWRMAX(:)) 00225 ! 00226 ! 00227 !* 3. LIQUID WATER REACHING THE GROUND Pg 00228 ! ----------------------------------- 00229 ! 00230 !Thus, the rate of liquid water reaching the ground is the 00231 !precipitation plus the vegetation runoff (we also consider the 00232 !negative runoff). 00233 ! 00234 PPG(:) = (1.-PVEG(:)*(1-PPSNV(:))) * PRR(:) + ZRUIR(:) + ZRUIR2(:) 00235 ! 00236 PDRIP(:) = ZRUIR(:) + ZRUIR2(:) 00237 IF (LHOOK) CALL DR_HOOK('HYDRO_VEG',1,ZHOOK_HANDLE) 00238 00239 ! 00240 !------------------------------------------------------------------------------- 00241 ! 00242 END SUBROUTINE HYDRO_VEG
1.8.0
