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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 LAILOSS(PVEG, PSEFOLD, PANMAX, PANDAY, PANFM, PBIOMASS) 00003 ! ############################################################### 00004 !!**** *LAILOSS* 00005 !! 00006 !! PURPOSE 00007 !! ------- 00008 ! 00009 ! Calculates the time change in LAI due to senesence 00010 ! and cutting: ie losses/decreases to LAI. This in turn 00011 ! reduces the dry biomass of the canopy. 00012 ! 00013 !!** METHOD 00014 !! ------ 00015 ! Calvet at al (1997) [from model of Jacobs(1994)] 00016 !! 00017 !! EXTERNAL 00018 !! -------- 00019 !! none 00020 !! 00021 !! IMPLICIT ARGUMENTS 00022 !! ------------------ 00023 !! 00024 !! none 00025 !! 00026 !! REFERENCE 00027 !! --------- 00028 !! 00029 !! Calvet et al. (1997) 00030 !! 00031 !! AUTHOR 00032 !! ------ 00033 !! 00034 !! A. Boone * Meteo-France * 00035 !! (following Belair) 00036 !! 00037 !! MODIFICATIONS 00038 !! ------------- 00039 !! Original 27/10/97 00040 !! Modified 12/03/04 by P LeMoigne: ZXSEFOLD in days 00041 !! L. Jarlan 27/10/04 add RHOA as input to express PANMAX in 00042 !! kgCO2 m-2s-1 instead of kgCO2 kgAir-1 m s-1 00043 !! P Le Moigne 09/2005 AGS modifs of L. Jarlan 00044 !! S. Lafont 03/2011 modification for consistency with nitro_decline 00045 !! 00046 !------------------------------------------------------------------------------- 00047 ! 00048 USE MODD_CSTS, ONLY : XDAY 00049 USE MODD_CO2V_PAR, ONLY: XMC, XMCO2, XPCCO2 00050 ! 00051 !* 0. DECLARATIONS 00052 ! ------------ 00053 ! 00054 ! 00055 ! 00056 USE YOMHOOK ,ONLY : LHOOK, DR_HOOK 00057 USE PARKIND1 ,ONLY : JPRB 00058 ! 00059 IMPLICIT NONE 00060 ! 00061 !* 0.1 declarations of arguments 00062 ! 00063 ! 00064 REAL, DIMENSION(:),INTENT(IN) :: PVEG ! vegetation fraction 00065 REAL, DIMENSION(:), INTENT(IN) :: PSEFOLD ! e-folding time for senescence (s) 00066 REAL, DIMENSION(:), INTENT(IN) :: PANMAX ! maximum photosynthesis rate 00067 REAL, DIMENSION(:), INTENT(IN) :: PANDAY ! daily net CO2 accumulation 00068 ! 00069 REAL, DIMENSION(:), INTENT(INOUT) :: PANFM ! maximum leaf assimilation 00070 REAL, DIMENSION(:), INTENT(INOUT) :: PBIOMASS ! total dry canopy biomass 00071 ! 00072 !* 0.2 declarations of local variables 00073 ! 00074 REAL, DIMENSION(SIZE(PSEFOLD)) :: ZXSEFOLD, ZXM 00075 REAL :: ZBMCOEF 00076 REAL(KIND=JPRB) :: ZHOOK_HANDLE 00077 ! 00078 !----------------------------------------------------------------- 00079 IF (LHOOK) CALL DR_HOOK('LAILOSS',0,ZHOOK_HANDLE) 00080 ! 00081 ZBMCOEF = XMC/(XMCO2*XPCCO2) 00082 ! 00083 ! Once a day (at midnight), adjust biomass: 00084 ! ---------------------------------------- 00085 ! 00086 WHERE((PVEG(:)>0) ) 00087 ! 00088 ! leaf life expectancy 00089 ! 00090 ZXSEFOLD(:) = PSEFOLD(:)*MIN(1.0, PANFM(:)/PANMAX(:))/XDAY 00091 ! 00092 ! avoid possible but unlikely division by zero 00093 ! 00094 ZXSEFOLD(:) = MAX(1.0E-8,ZXSEFOLD(:)) 00095 ! 00096 ! limitation of leaf life expectancy 00097 ! 00098 ZXSEFOLD(:) = MAX(5.,ZXSEFOLD(:)) 00099 ! 00100 ! senesence of active biomass 00101 ! 00102 ZXM(:) = PBIOMASS(:)*(1.0-EXP(-1.0/ZXSEFOLD(:))) 00103 ! 00104 ! decrease biomass: 00105 ! 00106 PBIOMASS(:) = PBIOMASS(:) - ZXM(:) 00107 ! 00108 ! same modification than nitro_decline.f90 00109 ! now the assimilation is added here 00110 ! in that way laigain.f90 is consistant between the different carbon options. 00111 PBIOMASS(:) = PBIOMASS(:) + PANDAY(:)*ZBMCOEF 00112 ! 00113 ! maximum leaf assimilation (kgCO2 kgAir-1 m s-1): 00114 ! 00115 PANFM(:) = 0.0 00116 ! 00117 END WHERE 00118 ! 00119 IF (LHOOK) CALL DR_HOOK('LAILOSS',1,ZHOOK_HANDLE) 00120 ! 00121 END SUBROUTINE LAILOSS
1.8.0
