Comments on "Isentropic Analysis of a Simulated Hurricane"

Abstract: This paper describes Comments to the paper of Mrowiec et al. published in the J. Atmos. Sci. in May 2016 (Vol 73, Issue 5, pages 1857-1870) and entitled "Isentropic analysis of a simulated hurricane". It is explained that the plotting of isentropic surfaces (namely the isentropes) requires a precise definition of the specific moist-air entropy, and that most of existing "equivalent potential temperatures" lead to inaccurate definitions of isentropes. It is shown that the use of the third law of thermodynamics leads to a definition of the specific moist-air entropy (and of a corresponding potential temperature) which allow the plotting of unambigous moist-air isentropes. Numerical applications are shown by using a numerical simulation of the hurricane DUMILE.