metpy.constants¶
This is a collection of meteorologically significant constants.
Earth¶
| Name | Abbr. | Units | Description |
| earth_avg_radius | Re | m | Avg. radius of the Earth |
| earth_gravity | g | m s^-2 | Avg. gravity acceleration on Earth |
| earth_avg_angular_vel | omega | rad s^-1 | Avg. angular velocity of Earth |
| earth_sfc_avg_dist_sun | d | m | Avg. distance of the Earth from the Sun |
| earth_solar_irradiance | S | W m^-2 | Avg. solar irradiance of Earth |
| earth_max_declination | delta | degrees | Max. solar declination angle of Earth |
| earth_orbit_eccentricity | None | Avg. eccentricity of Earth’s orbit |
Water¶
| Name | Abbr. | Units | Description |
| water_molecular_weight | Mw | g mol^-1 | Molecular weight of water |
| water_gas_constant | Rv | J (K kg)^-1 | Gas constant for water vapor |
| density_water | rho_l | kg m^-3 | Nominal density of liquid water at 0C |
| wv_specific_heat_press | Cp_v | J (K kg)^-1 | Specific heat at constant pressure for water vapor |
| wv_specific_heat_vol | Cv_v | J (K kg)^-1 | Specific heat at constant volume for water vapor |
| water_specific_heat | Cp_l | J (K kg)^-1 | Specific heat of liquid water at 0C |
| water_heat_vaporization | Lv | J kg^-1 | Latent heat of vaporization for liquid water at 0C |
| water_heat_fusion | Lf | J kg^-1 | Latent heat of fusion for liquid water at 0C |
| ice_specific_heat | Cp_i | J (K kg)^-1 | Specific heat of ice at 0C |
| density_ice | rho_i | kg m^-3 | Density of ice at 0C |
Dry Air¶
| Name | Abbr. | Units | Description |
| dry_air_molecular_weight | Md | g / mol | Nominal molecular weight of dry air at the surface of th Earth |
| dry_air_gas_constant | Rd | J (K kg)^-1 | Gas constant for dry air at the surface of the Earth |
| dry_air_spec_heat_press | Cp_d | J (K kg)^-1 | Specific heat at constant pressure for dry air |
| dry_air_spec_heat_vol | Cv_d | J (K kg)^-1 | Specific heat at constant volume for dry air |
| dry_air_density_stp | rho_d | kg m^-3 | Density of dry air at 0C and 1000mb |
General Meteorology Constants¶
| Name | Abbr. | Units | Description |
| pot_temp_ref_press | P0 | Pa | Reference pressure for potential temperature |
| poisson_exponent | kappa | None | Exponent in Poisson’s equation (Rd/Cp_d) |
| dry_adiabatic_lapse_rate | gamma_d | K km^-1 | The dry adiabatic lapse rate |
| molecular_weight_ratio | epsilon | None | Ratio of molecular weight of water to that of dry air |