phycon_module.f90

来自「CLM集合卡曼滤波数据同化算法」· F90 代码 · 共 57 行

 MODULE phycon_module

!=======================================================================
! Physical and model constants 
!
!      Source file: phycon_module.f90
! Original version: Yongjiu Dai, Yongjiu Dai, September 15, 1999
!
!=======================================================================
      IMPLICIT NONE
! physical constants
      real, parameter :: dice   = 917.     ! density of ice [kg/m3]
      real, parameter :: rhowat = 1000.    ! density of liquid water [kg/m3]
      real, parameter :: cl     = 4188.    ! Specific heat of water [J/kg-K]
      real, parameter :: ci     = 2117.27  ! Specific heat of ice [J/kg-K]
      real, parameter :: cp     = 1004.64  ! specific heat of dry air [J/kg/K]
      real, parameter :: dlm    = 0.3336e6 ! Latent heat of fusion for ice [J/kg]
      real, parameter :: dlv    = 2.5104e6 ! Latent heat of evap for water [J/kg]
      real, parameter :: dls    = 2.8440e6 ! Latent heat of sublimation [J/kg]
      real, parameter :: tkair  = 0.023    ! thermal conductivity of air [W/m/k]
      real, parameter :: tkice  = 2.290    ! thermal conductivity of ice [W/m/k]
      real, parameter :: tkwat  = 0.6      ! thermal conductivity of water [W/m/k]
      real, parameter :: tfrz   = 273.16   ! freezing temperature [K]
      real, parameter :: rgas   = 287.04   ! gas constant for dry air [J/kg/K]
      real, parameter :: roverg = 4.71047e4! Rw/g = (8.3144/0.018)/(9.80616)*1000. mm/K
      real, parameter :: rw     = 461.296  ! gas constant for water vapor [J/(kg K)]
      real, parameter :: grv    = 9.80616  ! gravity constant [m/s2]
      real, parameter :: vonkar = 0.4      ! von Karman constant [-]
      real, parameter :: stefnc = 5.67e-8  ! stefans constant  [W/m2/K4]

! Leaf constants
      real, parameter :: dewmx  = 0.1      ! maximum allowed dew [mm]

! Roughness lengths
      real, parameter :: zlnd   = 0.01     ! roughness length for soil [m]
      real, parameter :: zsno   = 0.0024   ! roughness length for snow [m]
      real, parameter :: csoilc = 0.004    ! drag coefficient for soil under canopy [-]

! Hydraulic constants of soil
      real, parameter :: basefl = 1.e-5    ! base flow rate (mm/s)
      real, parameter :: wtfact = 0.3      ! fraction of model area with high water table
      real, parameter :: trsmx0 = 2.e-4    ! max transpiration for moist soil+100% veg. [mm/s]
      real, parameter :: swt    = 0.90     ! value of soil wetness above which considered saturated

! Numerical finite-difference
      real, parameter :: capr   = 0.34     ! tuning factor to turn first layer T into surface T
      real, parameter :: cn     = 0.5      ! Crank Nicholson factor between 0 and 1

!*SOME ARE TUNABLE
      real, parameter :: tcrit  = 0.       !2.5      ! critical temp. to determine rain or snow 
      real, parameter :: smpmin = -1.e8    ! restriction for min of soil poten. (mm)
      real, parameter :: ssi    = 0.033    ! irreducible water saturation of snow
      real, parameter :: wimp   = 0.001    ! water impremeable if porosity < wimp
      real, parameter :: pondmx = 10.      ! ponding depth (mm)

 END MODULE phycon_module