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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! |
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!! !! |
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!! GNU General Public License !! |
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!! !! |
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!! This file is part of the Flexible Modeling System (FMS). !! |
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!! !! |
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!! FMS is free software; you can redistribute it and/or modify !! |
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!! it and are expected to follow the terms of the GNU General Public !! |
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!! License as published by the Free Software Foundation. !! |
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!! !! |
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!! FMS is distributed in the hope that it will be useful, !! |
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!! but WITHOUT ANY WARRANTY; without even the implied warranty of !! |
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!! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the !! |
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!! GNU General Public License for more details. !! |
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!! !! |
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!! You should have received a copy of the GNU General Public License !! |
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!! along with FMS; if not, write to: !! |
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!! Free Software Foundation, Inc. !! |
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!! 59 Temple Place, Suite 330 !! |
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!! Boston, MA 02111-1307 USA !! |
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!! or see: !! |
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!! http://www.gnu.org/licenses/gpl.txt !! |
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!! !! |
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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! |
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|
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module constants_mod |
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|
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! <CONTACT EMAIL="Bruce.Wyman@noaa.gov"> |
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! Bruce Wyman |
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! </CONTACT> |
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|
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! <HISTORY SRC="http://www.gfdl.noaa.gov/fms-cgi-bin/cvsweb.cgi/FMS/"/> |
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|
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! <OVERVIEW> |
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! Defines useful constants for Earth. |
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! </OVERVIEW> |
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|
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! <DESCRIPTION> |
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! Constants are defined as real parameters, |
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! except for PI and RADIAN, which are calculated in constants_init to promote |
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! consistency and accuracy among various compilers. |
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! |
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! Constants are accessed through the "use" statement. |
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! </DESCRIPTION> |
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|
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!use fms_mod, only: write_version_number |
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|
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implicit none |
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private |
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|
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character(len=128) :: version='$Id: constants_mod.F90,v 1.1 2012/09/11 03:53:04 jmc Exp $' |
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character(len=128) :: tagname='$Name: $' |
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logical :: do_log = .true. |
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logical :: module_is_initialized = .FALSE. |
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!dummy variable to use in HUGE initializations |
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real :: realnumber |
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|
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!------------ physical constants --------------- |
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! <DATA NAME="RADIUS" UNITS="m" TYPE="real" DEFAULT="6371.e3"> |
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! radius of the earth |
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! </DATA> |
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! <DATA NAME="OMEGA" UNITS="1/s" TYPE="real" DEFAULT="7.292e-5"> |
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! rotation rate of the planet (earth) |
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! </DATA> |
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! <DATA NAME="GRAV" UNITS="m/s^2" TYPE="real" DEFAULT="9.80"> |
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! acceleration due to gravity |
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! </DATA> |
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! <DATA NAME="RDGAS" UNITS="J/kg/deg" TYPE="real" DEFAULT="287.04"> |
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! gas constant for dry air |
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! </DATA> |
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! <DATA NAME="KAPPA" TYPE="real" DEFAULT="2./7."> |
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! RDGAS / CP_AIR |
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! </DATA> |
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! <DATA NAME="CP_AIR" UNITS="J/kg/deg" TYPE="real" DEFAULT="RDGAS/KAPPA"> |
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! specific heat capacity of dry air at constant pressure |
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! </DATA> |
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! <DATA NAME="CP_OCEAN" UNITS="J/kg/deg" TYPE="real" DEFAULT="3989.24495292815"> |
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! specific heat capacity taken from McDougall (2002) "Potential Enthalpy ..." |
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! </DATA> |
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! <DATA NAME="RHO0" UNITS="kg/m^3" TYPE="real" DEFAULT="1.035e3"> |
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! average density of sea water |
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! </DATA> |
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! <DATA NAME="RHO0R" UNITS="m^3/kg" TYPE="real" DEFAULT="1.0/RHO0"> |
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! reciprocal of average density of sea water |
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! </DATA> |
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! <DATA NAME="RHO_CP" UNITS="J/m^3/deg" TYPE="real" DEFAULT="RHO0*CP_OCEAN"> |
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! (kg/m^3)*(cal/kg/deg C)(joules/cal) = (joules/m^3/deg C) |
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! </DATA> |
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|
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real, public, parameter :: RADIUS = 6371.0e3 |
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real, public, parameter :: OMEGA = 7.292e-5 |
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real, public, parameter :: GRAV = 9.80 |
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real, public, parameter :: RDGAS = 287.04 |
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real, public, parameter :: KAPPA = 2./7. |
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real, public, parameter :: CP_AIR = RDGAS/KAPPA |
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real, public, parameter :: CP_OCEAN = 3989.24495292815 |
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real, public, parameter :: RHO0 = 1.035e3 |
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real, public, parameter :: RHO0R = 1.0/RHO0 |
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real, public, parameter :: RHO_CP = RHO0*CP_OCEAN |
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|
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!------------ water vapor constants --------------- |
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! <DATA NAME="RVGAS" UNITS="J/kg/deg" TYPE="real" DEFAULT="461.50"> |
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! gas constant for water vapor |
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! </DATA> |
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! <DATA NAME="DENS_H2O" UNITS="kg/m^3" TYPE="real" DEFAULT="1000."> |
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! density of liquid water |
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! </DATA> |
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! <DATA NAME="HLV" UNITS="J/kg" TYPE="real" DEFAULT="2.500e6"> |
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! latent heat of evaporation |
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! </DATA> |
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! <DATA NAME="HLF" UNITS="J/kg" TYPE="real" DEFAULT="3.34e5"> |
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! latent heat of fusion |
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! </DATA> |
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! <DATA NAME="HLS" UNITS="J/kg" TYPE="real" DEFAULT="2.834e6"> |
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! latent heat of sublimation |
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! </DATA> |
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! <DATA NAME="TFREEZE" UNITS="degK" TYPE="real" DEFAULT="273.16"> |
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! temp where fresh water freezes |
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! </DATA> |
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|
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real, public, parameter :: RVGAS = 461.50 |
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real, public, parameter :: DENS_H2O = 1000. |
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real, public, parameter :: HLV = 2.500e6 |
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real, public, parameter :: HLF = 3.34e5 |
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real, public, parameter :: HLS = 2.834e6 |
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real, public, parameter :: TFREEZE = 273.16 |
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|
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!-------------- radiation constants ----------------- |
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|
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! <DATA NAME="WTMAIR" UNITS="AMU" TYPE="real" DEFAULT="2.896440E+01"> |
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! molecular weight of air |
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! </DATA> |
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! <DATA NAME="WTMH2O" UNITS="AMU" TYPE="real" DEFAULT="1.801534E+01"> |
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! molecular weight of water |
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! </DATA> |
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! <DATA NAME="WTMO3" UNITS="AMU" TYPE="real" DEFAULT="47.99820E+01"> |
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! molecular weight of ozone |
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! </DATA> |
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! <DATA NAME="DIFFAC" TYPE="real" DEFAULT="1.660000E+00"> |
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! diffusivity factor |
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! </DATA> |
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! <DATA NAME="SECONDS_PER_DAY" UNITS="seconds" TYPE="real" DEFAULT="8.640000E+04"> |
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! seconds in a day |
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! </DATA> |
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! <DATA NAME="AVOGNO" UNITS="atoms/mole" TYPE="real" DEFAULT="6.023000E+23"> |
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! Avogadro's number |
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! </DATA> |
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! <DATA NAME="PSTD" UNITS="dynes/cm^2" TYPE="real" DEFAULT="1.013250E+06"> |
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! mean sea level pressure |
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! </DATA> |
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! <DATA NAME="PSTD_MKS" UNITS="Newtons/m^2" TYPE="real" DEFAULT="101325.0"> |
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! mean sea level pressure |
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! </DATA> |
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! <DATA NAME="REARTH" UNITS="cm" TYPE="real" DEFAULT="6.356766E+08"> |
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! radius of the earth |
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! </DATA> |
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|
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real, public, parameter :: WTMAIR = 2.896440E+01 |
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real, public, parameter :: WTMH2O = 1.801534E+01 |
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real, public, parameter :: WTMO3 = 47.99820E+01 |
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real, public, parameter :: DIFFAC = 1.660000E+00 |
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real, public, parameter :: SECONDS_PER_DAY = 8.640000E+04 |
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real, public, parameter :: AVOGNO = 6.023000E+23 |
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real, public, parameter :: PSTD = 1.013250E+06 |
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real, public, parameter :: PSTD_MKS = 101325.0 |
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real, public, parameter :: REARTH = 6.356766E+08 |
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|
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! <DATA NAME="RADCON" UNITS="deg sec/(cm day)" TYPE="real" DEFAULT="((1.0E+02*GRAV)/(1.0E+04*CP_AIR))*SECONDS_PER_DAY"> |
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! factor used to convert flux divergence to heating rate in degrees per day |
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! </DATA> |
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! <DATA NAME="RADCON_MKS" UNITS="deg sec/(m day)" TYPE="real" DEFAULT="(GRAV/CP_AIR)*SECONDS_PER_DAY"> |
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! factor used to convert flux divergence to heating rate in degrees per day |
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! </DATA> |
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! <DATA NAME="O2MIXRAT" TYPE="real" DEFAULT="2.0953E-01"> |
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! mixing ratio of molecular oxygen in air |
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! </DATA> |
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! <DATA NAME="RHOAIR" UNITS="kg/m^3" TYPE="real" DEFAULT="1.292269"> |
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! reference atmospheric density |
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! </DATA> |
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! <DATA NAME="ALOGMIN" TYPE="real" DEFAULT="-50.0"> |
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! minimum value allowed as argument to log function |
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! </DATA> |
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! <DATA NAME="FREZDK" UNITS="deg K" TYPE="real" DEFAULT="273.16"> |
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! melting point of water |
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! </DATA> |
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|
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real, public, parameter :: RADCON = ((1.0E+02*GRAV)/(1.0E+04*CP_AIR))*SECONDS_PER_DAY |
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real, public, parameter :: RADCON_MKS = (GRAV/CP_AIR)*SECONDS_PER_DAY |
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real, public, parameter :: O2MIXRAT = 2.0953E-01 |
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real, public, parameter :: RHOAIR = 1.292269 |
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real, public, parameter :: ALOGMIN = -50.0 |
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real, public, parameter :: FREZDK = 273.16 |
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|
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!------------ miscellaneous constants --------------- |
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! <DATA NAME="STEFAN" UNITS="W/m^2/deg^4" TYPE="real" DEFAULT="5.6734e-8"> |
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! Stefan-Boltzmann constant |
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! </DATA> |
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! <DATA NAME="VONKARM" TYPE="real" DEFAULT="0.40"> |
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! Von Karman constant |
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! </DATA> |
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! <DATA NAME="PI" TYPE="real" DEFAULT="4.0*ATAN(1.0)"> |
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! ratio of circle circumference to diameter |
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! </DATA> |
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! <DATA NAME="RADIAN" TYPE="real" DEFAULT="180.0/PI"> |
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! degrees per radian |
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! </DATA> |
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! <DATA NAME="C2DBARS" UNITS="dbars" TYPE="real" DEFAULT="1.e-4"> |
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! converts rho*g*z (in mks) to dbars: 1dbar = 10^4 (kg/m^3)(m/s^2)m |
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! </DATA> |
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! <DATA NAME="KELVIN" TYPE="real" DEFAULT="273.15"> |
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! degrees Kelvin at zero Celsius |
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! </DATA> |
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! <DATA NAME="EPSLN" TYPE="real" DEFAULT="1.0e-40"> |
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! a small number to prevent divide by zero exceptions |
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! </DATA> |
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|
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real, public, parameter :: STEFAN = 5.6734e-8 |
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real, public, parameter :: VONKARM = 0.40 |
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real, public :: PI = HUGE(realnumber) |
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real, public :: RADIAN = HUGE(realnumber) |
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real, public, parameter :: C2DBARS = 1.e-4 |
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real, public, parameter :: KELVIN = 273.15 |
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real, public, parameter :: EPSLN = 1.0e-40 |
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!----------------------------------------------------------------------- |
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|
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public constants_init |
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|
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contains |
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|
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! <SUBROUTINE NAME="constants_init"> |
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|
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! <OVERVIEW> |
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! Initialization routine. The purpose of this routine |
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! is initialize the value of PI and RADIAN, and to write the |
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! version and tag name information to the log file. |
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! </OVERVIEW> |
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! <DESCRIPTION> |
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! If this routine is called more than once or called |
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! from other than the root PE it will return silently. |
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! There are no arguments. |
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! </DESCRIPTION> |
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! <TEMPLATE> |
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! call constants_init |
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! </TEMPLATE> |
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|
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subroutine constants_init |
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|
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if (module_is_initialized) return |
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module_is_initialized = .TRUE. |
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|
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if (.not.do_log) return |
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! call write_version_number (version,tagname) |
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do_log = .false. |
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|
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PI = 4.0*ATAN(1.0) |
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RADIAN = 180.0/PI |
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|
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end subroutine constants_init |
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! </SUBROUTINE> |
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|
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!----------------------------------------------------------------------- |
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|
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end module constants_mod |
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|
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! <INFO> |
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|
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! <FUTURE> |
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! 1. Renaming of constants. |
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! </FUTURE> |
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! <FUTURE> |
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! 2. Additional constants. |
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! </FUTURE> |
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! <NOTE> |
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! Constants have been declared as type REAL, PARAMETER. |
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! |
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! The value a constant can not be changed in a users program. |
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! New constants can be defined in terms of values from the |
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! constants module using a parameter statement.<br><br> |
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! |
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! The name given to a particular constant may be changed.<br><br> |
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! |
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! Constants can be used on the right side on an assignment statement |
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! (their value can not be reassigned). |
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! |
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! As PI is calculated, it cannot be a parameter variable. |
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! Do not assign a new value to PI. |
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! |
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!<TESTPROGRAM NAME="EXAMPLE"> |
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!<PRE> |
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! use constants_mod, only: TFREEZE, grav_new => GRAV |
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! real, parameter :: grav_inv = 1.0 / grav_new |
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! tempc(:,:,:) = tempk(:,:,:) - TFREEZE |
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! geopotential(:,:) = height(:,:) * grav_new |
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!</PRE> |
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!</TESTPROGRAM> |
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! </NOTE> |
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|
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! </INFO> |
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