a = 6.373E6 % Radius of Earth (m)
Lhvap = 2.5E6 % Latent heat of vaporization (J / kg)
Lhsub = 2.834E6 % Latent heat of sublimation (J / kg)
Lhfus = Lhsub - Lhvap % Latent heat of fusion (J / kg)
cp = 1004.07 % specific heat at constant pressure for dry air (J / kg / K)
Rd = 287. % gas constant for dry air (J / kg / K)
kappa = Rd / cp
Rv = 461.5 % gas constant for water vapor (J / kg / K)
cpv = 1875. % specific heat at constant pressure for water vapor (J / kg / K)
Omega = 2 * pi / 24. / 3600. % Earth's rotation rate, (s.^(-1))
g = 9.8 % gravitational acceleration (m / s.^2)
kBoltzmann = 1.3806488E-23 % the Boltzmann constant (J / K)
c_light = 2.99792458E8 % speed of light (m/s)
hPlanck = 6.62606957E-34 % Planck's constant (J s)
% sigma = 5.67E-8 % Stefan-Boltzmann constant (W / m.^2 / K.^4)
% sigma derived from fundamental constants
sigma = (2*pi.^5 * kBoltzmann.^4) / (15 * c_light.^2 * hPlanck.^3)
S0 = 1365.2 % solar constant (W / m.^2)
% value is consistent with Trenberth and Fasullo, Surveys of Geophysics 2012
ps = 1000. % approximate surface pressure (mb or hPa)
rho_w = 1000. % density of water (kg / m.^3)
cw = 4181.3 % specific heat of liquid water (J / kg / K)
tempCtoK = 273.15 % 0degC in Kelvin
tempKtoC = -tempCtoK % 0 K in degC
mb_to_Pa = 100. % conversion factor from mb to Pa
% Some useful time conversion factors
seconds_per_minute = 60.
minutes_per_hour = 60.
hours_per_day = 24.
% the length of the "tropical year" -- time between vernal equinoxes
% This value is consistent with Berger (1978)
% "Long-Term Variations of Daily Insolation and Quaternary Climatic Changes"
days_per_year = 365.2422
seconds_per_hour = minutes_per_hour * seconds_per_minute
minutes_per_day = hours_per_day * minutes_per_hour
seconds_per_day = hours_per_day * seconds_per_hour
seconds_per_year = seconds_per_day * days_per_year
minutes_per_year = seconds_per_year / seconds_per_minute
hours_per_year = seconds_per_year / seconds_per_hour
% average lenghts of months based on dividing the year into 12 equal parts
months_per_year = 12.
seconds_per_month = seconds_per_year / months_per_year
minutes_per_month = minutes_per_year / months_per_year
hours_per_month = hours_per_year / months_per_year
days_per_month = days_per_year / months_per_year
area_earth = 4 * pi * a.^2
save constants
