R_d = 287.058 # Gas constant for dry air.
c_p = 1006 # Specific heat capacity of dry air at constant pressure at 273 K.
epsilon = 0.622 # Conversion factor for water vapour mixing ratio.
l_v = 2.501e6 # Latent heat of vaporization at 0 C (J.kg-1).
g0 = 9.80665 # Globally averaged acceleration of gravity at sea level.

