Equivalent temperature

From Glossary of Meteorology

equivalent temperature

  1. Isobaric equivalent temperature: The temperature that an air parcel would have if all water vapor were condensed at constant pressure and the enthalpy released from the vapor used to heat the air:

    where Tie is the isobaric equivalent temperature, T the temperature, w the mixing ratio, L the latent heat, and cp the specific heat of air at constant pressure. This process is physically impossible in the atmosphere.

  2. Adiabatic equivalent temperature (also known as pseudoequivalent temperature): The temperature that an air parcel would have after undergoing the following process: dry-adiabatic expansion until saturated; pseudoadiabatic expansion until all moisture is precipitated out; dry- adiabatic compression to the initial pressure.

    This is the equivalent temperature as read from a thermodynamic chart and is always greater than the isobaric equivalent temperature:
    where Tae is the adiabatic equivalent temperature.

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