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Question: Definition of Saturation Wet-bulb Potential Temperature


I am looking for a formal definition of Saturation Wet-bulb Potential Temperature and how it is calculated. Originally I assumed the obvious and considered a saturated parcel (Tair =Twb) brought moist-adiabatically to the 1000mb reference pressure to get the saturation wet-bulb potential temperature.

After using this for a while I am not sure I am correct, as the results I am getting just seem off. (The gory details of how I am using it won't be especially helpful--either I am using the correct definition and my intuition is faulty, or I am wrong and need to keep looking for the correct definition.)

Before posting, I started doing a lot of checking, and in the literature the term "saturation wet-bulb potential temperature" is generally used without definition, which suggests the term is obvious to the intended audience and needs no formal definition. Even as far back as 1962, Browning & Ludlam used it without definition in Airflow in Convective Storms (Quart. J. Royal Met. Soc.)

So in short: is the definition of "saturation wet-bulb potential temperature" I am using (posted above) correct? Thanks for any help.
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