122 lines
8.2 KiB
Python
122 lines
8.2 KiB
Python
# Copyright (c) 2008,2015,2016,2018 MetPy Developers.
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# Distributed under the terms of the BSD 3-Clause License.
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# SPDX-License-Identifier: BSD-3-Clause
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r"""A collection of meteorologically significant constant and thermophysical property values.
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Earth
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-----
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======================== =============== =========== ======================================= ===============================================================
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Name Symbol Short Name Units Description
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------------------------ --------------- ----------- --------------------------------------- ---------------------------------------------------------------
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earth_avg_radius :math:`R_e` Re :math:`\text{m}` Avg. radius of the Earth [1]_
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earth_gravity :math:`g` g :math:`\text{m s}^{-2}` Avg. gravity acceleration on Earth [2]_
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gravitational_constant :math:`G` G :math:`\text{m}^{3} {kg}^{-1} {s}^{-2}` Gravitational constant [2]_
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earth_avg_angular_vel :math:`\Omega` omega :math:`\text{rad s}^{-1}` Avg. angular velocity of Earth [1]_
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earth_sfc_avg_dist_sun :math:`d` d :math:`\text{m}` Avg. distance of the Earth from the Sun [3]_
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earth_solar_irradiance :math:`S` S :math:`\text{W m}^{-2}` Avg. solar irradiance of Earth [4]_
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earth_max_declination :math:`\delta` delta :math:`\text{degrees}` Max. solar declination angle of Earth
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earth_orbit_eccentricity :math:`e` :math:`\text{None}` Avg. eccentricity of Earth's orbit
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earth_mass :math:`m_e` me :math:`\text{kg}` Total mass of the Earth (approx) [1]_ [2]_
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======================== =============== =========== ======================================= ===============================================================
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Water
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-----
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======================= ================ ========== ============================ ====================================================
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Name Symbol Short Name Units Description
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----------------------- ---------------- ---------- ---------------------------- ----------------------------------------------------
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water_molecular_weight :math:`M_w` Mw :math:`\text{g mol}^{-1}` Molecular weight of water [5]_
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water_gas_constant :math:`R_v` Rv :math:`\text{J (K kg)}^{-1}` Gas constant for water vapor [2]_ [5]_
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density_water :math:`\rho_l` rho_l :math:`\text{kg m}^{-3}` Maximum recommended density of liquid water, 0-40C [5]_
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wv_specific_heat_press :math:`C_{pv}` Cp_v :math:`\text{J (K kg)}^{-1}` Specific heat at constant pressure for water vapor
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wv_specific_heat_vol :math:`C_{vv}` Cv_v :math:`\text{J (K kg)}^{-1}` Specific heat at constant volume for water vapor
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water_specific_heat :math:`Cp_l` Cp_l :math:`\text{J (K kg)}^{-1}` Specific heat of liquid water at 0C [6]_
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water_heat_vaporization :math:`L_v` Lv :math:`\text{J kg}^{-1}` Latent heat of vaporization for liquid water at 0C [7]_
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water_heat_fusion :math:`L_f` Lf :math:`\text{J kg}^{-1}` Latent heat of fusion for liquid water at 0C [7]_
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ice_specific_heat :math:`C_{pi}` Cp_i :math:`\text{J (K kg)}^{-1}` Specific heat of ice at 0C [7]_
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density_ice :math:`\rho_i` rho_i :math:`\text{kg m}^{-3}` Density of ice at 0C
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======================= ================ ========== ============================ ====================================================
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Dry Air
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-------
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======================== ================ ============= ============================ ====================================================================
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Name Symbol Short Name Units Description
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------------------------ ---------------- ------------- ---------------------------- --------------------------------------------------------------------
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dry_air_molecular_weight :math:`M_d` Md :math:`\text{g / mol}` Nominal molecular weight of dry air at the surface of th Earth [8]_
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dry_air_gas_constant :math:`R_d` Rd :math:`\text{J (K kg)}^{-1}` Gas constant for dry air at the surface of the Earth
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dry_air_spec_heat_press :math:`C_{pd}` Cp_d :math:`\text{J (K kg)}^{-1}` Specific heat at constant pressure for dry air
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dry_air_spec_heat_vol :math:`C_{vd}` Cv_d :math:`\text{J (K kg)}^{-1}` Specific heat at constant volume for dry air
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dry_air_density_stp :math:`\rho_d` rho_d :math:`\text{kg m}^{-3}` Density of dry air at 0C and 1000mb
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======================== ================ ============= ============================ ====================================================================
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General Meteorology Constants
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-----------------------------
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======================== ================= =========== ========================= =======================================================
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Name Symbol Short Name Units Description
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------------------------ ----------------- ----------- ------------------------- -------------------------------------------------------
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pot_temp_ref_press :math:`P_0` P0 :math:`\text{Pa}` Reference pressure for potential temperature
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poisson_exponent :math:`\kappa` kappa :math:`\text{None}` Exponent in Poisson's equation (Rd/Cp_d)
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dry_adiabatic_lapse_rate :math:`\gamma_d` gamma_d :math:`\text{K km}^{-1}` The dry adiabatic lapse rate
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molecular_weight_ratio :math:`\epsilon` epsilon :math:`\text{None}` Ratio of molecular weight of water to that of dry air
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======================== ================= =========== ========================= =======================================================
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.. [1] [Moritz2000]_
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.. [2] [CODATA2018]_
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.. [3] [IAU2012]_
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.. [4] [Kopp2011]_
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.. [5] [IAPWS2001]_
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.. [6] [IAPWS1995]_
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.. [7] [WMO1966]_
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.. [8] [Picard2008]_
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""" # noqa: E501
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# Earth
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earth_gravity = g = 9.80665 # 'm / s^2'
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Re = earth_avg_radius = 6371008.7714 # 'm'
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G = gravitational_constant = 6.67430e-11 # 'm^3 / kg / s^2'
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GM = geocentric_gravitational_constant = 3986005e8 # 'm^3 / s^2'
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omega = earth_avg_angular_vel = 7292115e-11 # 'rad / s'
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d = earth_sfc_avg_dist_sun = 149597870700. # 'm'
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S = earth_solar_irradiance = 1360.8 # 'W / m^2'
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delta = earth_max_declination = 23.45 # 'degrees'
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earth_orbit_eccentricity = 0.0167 # 'dimensionless'
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earth_mass = me = geocentric_gravitational_constant / gravitational_constant
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# molar gas constant
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R = 8.314462618 # 'J / mol / K'
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# Water
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Mw = water_molecular_weight = 18.015268 # 'g / mol'
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Rv = water_gas_constant = R / Mw
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rho_l = density_water = 999.97495 # 'kg / m^3'
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wv_specific_heat_ratio = 1.330 # 'dimensionless'
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Cp_v = wv_specific_heat_press = (
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wv_specific_heat_ratio * Rv / (wv_specific_heat_ratio - 1)
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)
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Cv_v = wv_specific_heat_vol = Cp_v / wv_specific_heat_ratio
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Cp_l = water_specific_heat = 4.2194 # 'kJ / kg / K'
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Lv = water_heat_vaporization = 2.50084e6 # 'J / kg'
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Lf = water_heat_fusion = 3.337e5 # 'J / kg'
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Cp_i = ice_specific_heat = 2090 # 'J / kg / K'
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rho_i = density_ice = 917 # 'kg / m^3'
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# Dry air
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Md = dry_air_molecular_weight = 28.96546e-3 # 'kg / mol'
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Rd = dry_air_gas_constant = R / Md
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dry_air_spec_heat_ratio = 1.4 # 'dimensionless'
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Cp_d = dry_air_spec_heat_press = (
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dry_air_spec_heat_ratio * Rd / (dry_air_spec_heat_ratio - 1)
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)
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Cv_d = dry_air_spec_heat_vol = Cp_d / dry_air_spec_heat_ratio
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#TODO : check unit conversion
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rho_d = dry_air_density_stp = (1000., 'mbar') / (Rd * 273.15, 'K'))
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).to('kg / m^3')
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# General meteorology constants
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P0 = pot_temp_ref_press = 1000. # 'mbar'
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#TODO : check unit conversion
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kappa = poisson_exponent = (Rd / Cp_d).to('dimensionless')
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gamma_d = dry_adiabatic_lapse_rate = g / Cp_d
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#TODO : check unit conversion
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epsilon = molecular_weight_ratio = (Mw / Md).to('dimensionless')
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