SNOWPACK 20230601.f8ec41a
Constants.h File Reference
#include <cstddef>

Go to the source code of this file.


namespace  Constants


#define STR1(x)   #x
 _VERSION is given as a compilation flag to tell us what is the version number
Please only use SN_VERSION in the code More...
#define STR2(x)   STR1(x)
#define INIT_STABILITY   999.
 Initial value for stability parameter. More...


const double Constants::undefined = -999.
 This is the snowpack undefined value. More...
const int Constants::iundefined = -999
 This is the snowpack undefined value. More...
const size_t Constants::stundefined = static_cast<size_t>(-999)
const double Constants::min_percent_values = 0.9
const double Constants::pi = 3.14159265358979323846
const double Constants::g = 9.80665
const double Constants::stefan_boltzmann = 5.67051e-8
const double Constants::solcon = 1366.1
 Total Solar Irradiance (W m-2) (Froehlich, 2006) More...
const double Constants::gas_constant = 461.9
 (J kg-1 K-1) More...
const double Constants::gas_constant_air = 287.0
 for air (J kg-1 K-1) More...
const double Constants::gas_constant_mol = 8.31
 (J mol-1 K-1) More...
const double Constants::karman = 0.4
 Karman constant. More...
Albedo (1)
const double Constants::min_albedo = 0.3
const double Constants::max_albedo = 0.9
const double Constants::glacier_albedo = 0.3
Emissivity (1)
const double Constants::emissivity_snow = 0.98
const double Constants::emissivity_soil = 0.95
Density (kg m-3)
const double Constants::density_air = 1.1
 Approximation: use ideal gas law. More...
const double Constants::density_ice = 917.0
 At T = 0 degC. More...
const double Constants::density_water = 1000.0
 At T = 0 degC. More...
const double Constants::density_vapor = 1.0
 Approximation: use ideal gas law. More...
Specific heat (J kg-1 K-1)
const double Constants::specific_heat_ice = 2100.0
 at T = 0 degC More...
const double Constants::specific_heat_water = 4190.0
 at T = 0 degC More...
const double Constants::specific_heat_air = 1004.67
 see Stull "Meteorology for scientists and engineers" p44 More...
Thermal conductivity of snow components ice, water and air (W m-1 K-1)
const double Constants::conductivity_ice = 2.2
 (W m-1 K-1) More...
const double Constants::conductivity_water = 0.598
 (W m-1 K-1) More...
const double Constants::conductivity_air = 0.026
 (W m-1 K-1) More...
Vapor Diffusion in Air and Snow (m2 s-1)
const double Constants::diffusion_coefficient_in_air = 22.0e-6
 This value was taken from: Colbeck, S.C., 1993. The vapor diffusion coefficient for snow, Water Resources Research, 29(1) More...
const double Constants::diffusion_coefficient_in_snow = 85.0e-6
 It is larger (see Colbeck) according to work prior to 2008! More...
Phase change constants
const double Constants::meltfreeze_tk = 273.15
 (K) More...
const double Constants::triple_point_t = 273.16
 (K) More...
const double Constants::triple_point_p = 611.73
 (Pa) More...
const double Constants::lh_sublimation = 2.838e6
 (J kg-1) (solid to vapor) More...
const double Constants::lh_vaporization = 2.504e6
 (J kg-1) (liquid to vapor) More...
const double Constants::lh_fusion = 3.34e5
 (J kg-1) (solid to liquid) More...
Numerical Constants
const double Constants::min_slope_angle = 3.
 Smallest angle a flat field may show (deg) More...
const double Constants::eps = 1.e-6
 Small numbers for comparisons and to avoid divisions by zero. More...
const double Constants::eps2 = eps*eps
const double Constants::big = 1.0e200
 used for Dirichlet boundary conditions More...

Detailed Description

10.02 This module defines constants needed for the 1d snowpack model

Macro Definition Documentation


#define INIT_STABILITY   999.

Initial value for stability parameter.



◆ STR1

#define STR1 (   x)    #x

_VERSION is given as a compilation flag to tell us what is the version number
Please only use SN_VERSION in the code

◆ STR2

#define STR2 (   x)    STR1(x)