Evaporative available potential energy

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evaporative available potential energy

(Abbreviated EAPE.) Analogous to convective available potential energy, except that it is related to the negative buoyancy associated with evaporative cooling of liquid water within a sinking cloudy air parcel.

On a thermodynamic diagram, if a line is drawn corresponding to a sinking cloudy air parcel (follow a moist adiabat downward while the parcel is cloudy, and then after all liquid water has evaporated, continue below cloud base by following a dry adiabat), the EAPE is the area between this air-parcel line and a line corresponding to the environmental sounding. The resulting EAPE can be related to the kinetic energy associated with a negatively buoyant, sinking air parcel, and is useful for determining attributes of downdrafts and downbursts from thunderstorms.

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