Constants.h File Reference

#include <cstddef>

Go to the source code of this file.

Namespaces
namespace	Constants

Macros
#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	SN_VERSION   STR2( _VERSION )

Variables
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

Version

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

Macro Definition Documentation

SN_VERSION

#define SN_VERSION   STR2( _VERSION )

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)