ERF_Constants.H

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#ifndef ERF_CONSTANTS_H_
#define ERF_CONSTANTS_H_
 
#include <AMReX_REAL.H>
 
constexpr amrex::Real PI           = 3.14159265358979323846264338327950288;
constexpr amrex::Real PIoTwo       = PI/2.0;
 
// Physical Constants
constexpr amrex::Real R_d          = 287.0;    // dry air constant for dry air [J/(kg-K)]
constexpr amrex::Real R_v          = 461.505;  // water vapor constant for water vapor [J/(kg-K)]
constexpr amrex::Real Cp_d         = 1004.5;   // We have set this so that with qv=0 we get identically gamma = 1.4
constexpr amrex::Real Cp_v         = 1859.0;
constexpr amrex::Real Cp_l         = 4200.0;
 
constexpr amrex::Real L_v          = 2.5e6;    // latent heat of vaporization (J / kg)
 
constexpr amrex::Real p_0          = 1.0e5;    // reference surface pressure [Pa]
constexpr amrex::Real Gamma        = 1.4;      // c_p / c_v [-]
constexpr amrex::Real KAPPA        = 0.41;     // von Karman constant
constexpr amrex::Real CONST_GRAV   = 9.81;
 
// Derived Constants
constexpr amrex::Real ip_0         = 1./p_0;
constexpr amrex::Real iR_d         = 1./R_d;
constexpr amrex::Real iGamma       = 1./Gamma;
 
constexpr amrex::Real rhor         = 1000.; // Density of water, kg/m3
constexpr amrex::Real rhos         = 100.;  // Density of snow, kg/m3
constexpr amrex::Real rhog         = 400.;  // Density of graupel, kg/m3
constexpr amrex::Real tbgmin       = 253.16;    // Minimum temperature for cloud water., K
constexpr amrex::Real tbgmax       = 273.16;    // Maximum temperature for cloud ice, K
constexpr amrex::Real tprmin       = 268.16;    // Minimum temperature for rain, K
constexpr amrex::Real tprmax       = 283.16;    // Maximum temperature for snow+graupel, K
constexpr amrex::Real tgrmin       = 223.16;    // Minimum temperature for graupel, K
constexpr amrex::Real tgrmax       = 283.16;    // Maximum temperature for graupel, K
 
constexpr amrex::Real a_rain       = 842.;   // Coeff.for rain term vel
constexpr amrex::Real b_rain       = 0.8;    // Fall speed exponent for rain
constexpr amrex::Real a_snow       = 4.84;   // Coeff.for snow term vel
constexpr amrex::Real b_snow       = 0.25;   // Fall speed exponent for snow
constexpr amrex::Real a_grau       = 94.5;   // Lin (1983) (rhog=400)
constexpr amrex::Real b_grau       = 0.5;    // Fall speed exponent for graupel
 
// Autoconversion
constexpr amrex::Real qcw0         = 1.e-3;  // Threshold for water autoconversion, g/g
constexpr amrex::Real qci0         = 1.e-4;  // Threshold for ice autoconversion, g/g
constexpr amrex::Real alphaelq     = 1.e-3;  // autoconversion of cloud water rate coef
constexpr amrex::Real betaelq      = 1.e-3;  // autoconversion of cloud ice rate coef
 
constexpr amrex::Real erccoef      = 1.0;    // Rain/Cloud water collection efficiency
constexpr amrex::Real esccoef      = 1.0;    // Snow/Cloud water collection efficiency
constexpr amrex::Real esicoef      = 0.1;    // Snow/cloud ice collection efficiency
constexpr amrex::Real egccoef      = 1.0;    // Graupel/Cloud water collection efficiency
constexpr amrex::Real egicoef      = 0.1;    // Graupel/Cloud ice collection efficiency
 
constexpr amrex::Real nzeror       = 8.e6;   // Intercept coeff. for rain
constexpr amrex::Real nzeros       = 3.e6;   // Intersept coeff. for snow
constexpr amrex::Real nzerog       = 4.e6;   // Intersept coeff. for graupel
constexpr amrex::Real qp_threshold = 1.e-8;  // minimal rain/snow water content
 
constexpr amrex::Real boltz    = 1.38065e-23;
constexpr amrex::Real avogadro = 6.02214e26;
constexpr amrex::Real mwdair   = 28.966;
constexpr amrex::Real mwwv     = 18.016;
constexpr amrex::Real lcond    = 2.501e6;
constexpr amrex::Real lfus     = 2.11727e3;
constexpr amrex::Real lsub     = lcond+lfus;
constexpr amrex::Real rair     = boltz*avogadro/mwdair;
constexpr amrex::Real rh20     = rair/mwwv;
constexpr amrex::Real rga      = 1.0/CONST_GRAV;
 
constexpr amrex::Real diffelq = 2.21e-05;     // Diffusivity of water vapor, m2/s
constexpr amrex::Real therco  = 2.40e-02;     // Thermal conductivity of air, J/m/s/K
constexpr amrex::Real muelq   = 1.717e-05;    // Dynamic viscosity of air
 
constexpr amrex::Real a_bg = 1.0/(tbgmax-tbgmin);
constexpr amrex::Real a_pr = 1.0/(tprmax-tprmin);
constexpr amrex::Real a_gr = 1.0/(tgrmax-tgrmin);
 
constexpr amrex::Real crain = b_rain / 4.0;
constexpr amrex::Real csnow = b_snow / 4.0;
constexpr amrex::Real cgrau = b_grau / 4.0;
 
constexpr amrex::Real lat_vap  = 2.5e6;     // Latent heat of vaporization (J/kg)
constexpr amrex::Real lat_ice  = 3.337e5;   // latent heat of fusion (J/kg)
constexpr amrex::Real Rd_on_Rv = R_d/R_v;
constexpr amrex::Real tmelt    = 273.15;  // melting temp.
constexpr amrex::Real h2otrip  = 273.15;  // Triple point temperature of water (K)
constexpr amrex::Real tboil    = 373.16;  // Boiling point of water at 1 atm (K)
constexpr amrex::Real ttrice   = 20.00;   // transition range from es over H2O to es over ice
constexpr amrex::Real epsilo   = Rd_on_Rv;
constexpr amrex::Real omeps    = 1. - epsilo;
constexpr amrex::Real rhoh2o   = 1.000e3;  // density of liquid water
#endif