2019/01/23 by Pascal Marquet, Marquet, Pascal
Earth and Planetary Sciences · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Atmospheric and Oceanic Physics (physics.ao-ph) #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Geophysics (physics.geo-ph) #Meteorological Phenomena and Simulations #Statistical Mechanics and Entropy #physics.ao-ph #physics.flu-dyn #physics.geo-ph
paper · pdf · doi:10.48550/arxiv.1901.08108
Paper with 14 pages, 6 Figures and 2 Tables. Paper submitted to the Monthly Weather Review on the 3rd of March, 2019. Revised version sent on the 19th of May, 2019. Revised version 2: enlarged Figures 5 and 6 and issues fixed in Eqs.(34)-(36)
openalex publication_date 2019/01/23 · arxiv created 2019/05/27 · arxiv updated 2019/05/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
It is important to be able to calculate the moist-air entropy of the atmosphere with precision. A potential temperature has already been defined from the third law of thermodynamics for this purpose. However, a doubt remains as to whether this entropy potential temperature can be represented with simple but accurate first- or second-order approximate formulas. These approximations are rigorously defined in this paper using mathematical arguments and numerical adjustments to some datasets. The differentials of these approximations lead to simple but accurate formulations for tendencies, gradients and turbulent fluxes of the moist-air entropy. Several physical consequences based on these approximations are described and can serve to better understand moist-air processes (like turbulence or diabatic forcing) or properties of certain moist-air quantities (like the static energies).