Equivalent potential temperature

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equivalent potential temperature

(Also called wet-equivalent potential temperature.) A thermodynamic quantity, with its natural logarithm proportional to the entropy of moist air, that is conserved in a reversible moist adiabatic process.

It is given most accurately as
ams2001glos-Ee56
where θe is the equivalent potential temperature, cpd is the heat capacity at constant pressure of dry air, rt is the total water mixing ratio, c is the heat capacity of liquid water, T is the temperature, Rd is the gas constant for dry air, pd is the partial pressure of dry air, p0 is a reference pressure (usually 100 kPa), Lv is the latent heat of vaporization, rv is the vapor mixing ratio, Rv is the gas constant for water vapor, and Η is the relative humidity. Neglect of the quantity rtc, where it appears, yields a simpler expression with good accuracy.

Paluch, I. 1979. J. Atmos. Sci.. 36. 2467–2478.

Emanuel, K. A. 1994. Atmospheric Convection. Oxford University Press, . 580 pp.

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