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Free keywords:
available potential energy; atmospheric thermodynamics; cloud physics
Abstract:
Atmospheric potential energy is typically divided into an available and a nonavailable part. In this article a hypothetical utilization of a fraction of the nonavailable potential energy is described. This part stems from the water vapor that can be converted into the liquid phase. An energy gain results when the potential energy of the condensate relative to a reference height exceeds the energy necessary to condensate the water vapor. It is shown that this can be the case in a saturated atmosphere without convective available potential energy. Finally, simulations with the numerical cloud model HURMOD are performed to estimate the usability of the device in practice. Indeed, a positive energy output results in a simulation with immediate gathering of the condensate. On the contrary, potential energy gained falls significantly short of the necessary energy for forming the condensate when a realistic cloud microphysical scheme allowing re-evaporation of condensate is applied. Taken together it can be concluded that, a utilization of atmospheric potential energy is hypothetically possible but the practical realization is probably not feasible.