Entropy and Potential Temperature

Hauf, T.; Höller, H.

doi:10.1175/1520-0469(1987)044<2887:eapt>2.0.co;2

Cited by 63 publications

(92 citation statements)

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“…It is shown in the following sections that it is impossible to compute all the terms forming the entropy budget equation. Nevertheless, it is possible to use the Third Law of thermodynamics to compute the moist air entropy in an absolute way, as explained in Hauf and Höller (1987) and Marquet (2011). This is done by setting the zero of entropies for the most stable crystalline form of all atmospheric species at 0 K. This paper explores new possibilities for computing and analyzing isenthalpic or isentropic processes in open systems, defined by h = Constant or s = Constant.…”

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confidence: 99%

On the computation of moist‐air specific thermal enthalpy

Marquet

2014

Quart J Royal Meteoro Soc

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The specific thermal enthalpy of a moist-air parcel is defined analytically following a method in which specific moist entropy is derived from the Third Law of thermodynamics. Specific thermal enthalpy is computed by integrating specific heat content with respect to absolute temperature and including the impacts of various latent heats (i.e., solid condensation, sublimation, melting, and evaporation). It is assumed that thermal enthalpies can be set to zero at 0 K for the solid form of the main chemically inactive components of the atmosphere (solid-α oxygen and nitrogen, hexagonal ice). The moist thermal enthalpy is compared to already existing formulations of moist static energy (MSE). It is shown that the differences between thermal enthalpy and the thermal part of MSE may be quite large. This prevents the use of MSE to evaluate the enthalpy budget of a moist atmosphere accurately, a situation that is particularly true when dry-air and cloud parcels mix because of entrainment/detrainment processes along the edges of cloud. Other differences are observed when MSE or moist-air thermal enthalpy is plotted on a psychrometric diagram or when vertical profiles of surface deficit are plotted.

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confidence: 99%

On the computation of moist‐air specific thermal enthalpy

Marquet

2014

Quart J Royal Meteoro Soc

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“…Schumann et al, 1987). As noted by Hauf and Höller (1987) however, entropy is conserved and so may have special advantages only in models of reversible rather than simply adiabatic processes, as often assumed. The stricter former condition implies the absence of irreversible composition changes due to phase transitions, chemical production, or mixing.…”

Section: Discussionmentioning

confidence: 99%

“…The stricter former condition implies the absence of irreversible composition changes due to phase transitions, chemical production, or mixing. This follows from the entropy balance equation, which contains entropy production and flux terms related to tracer tendencies dq i /dt (de Groot and Mazur, 1962;Hauf and Höller, 1987;Zdunkowski and Bott, 2004).…”

Section: Discussionmentioning

confidence: 99%

“…The physical reason for this is not just the compositional dependence of the gas constant or heat capacities via Equations (7)- (9), but also the fundamental fact that partial entropy of mixture components is greater than entropy of individual pure tracers as formally represented by the so-called mixing terms (de Groot and Mazur, 1962;Hauf and Höller, 1987;Zdunkowski and Bott, 2004). In addition to a complicated balance equation, the mixing terms make the diagnostics of temperature from entropy cumbersome.…”

Section: Discussionmentioning

confidence: 99%

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Using enthalpy as a prognostic variable in atmospheric modelling with variable composition

Akmaev

Juang

2008

Quart J Royal Meteoro Soc

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Specific enthalpy emerges from a general form of the internal energy equation as a convenient prognostic thermodynamic variable for atmospheric modelling with variable composition, including models of moist air. This choice presents a general and flexible alternative to the common formalism of virtual temperature employed in most numerical weather prediction and climate models to account for the presence of water vapour and other constituents. The new approach eliminates the need for additional terms in the energy equation, resulting from composition variations along the air-parcel trajectories and routinely neglected in models. This note presents a derivation of relevant equations from first principles and outlines the changes to existing model codes necessary to accommodate the new formulation. Published in

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“…Scientists in China and abroad have made efforts to solve this problem for quite a long time. To clarify the different influences from different condensation nuclei on adiabatic heating, several specific forms of potential temperature have appeared (Betts, 1973;Xie, 1978;Wang and Luo, 1980;Tripoli and Cotton, 1981;Pointin, 1984;Hauf and Holler, 1987;Wang et al, 1990;Wu et al, 1995;Rivas Soriano and García Díez, 1997;Ooyama, 2000). Schubert and Hausman (2001) presented the potential vorticity principle in nonhydrostatic and Corresponding author: CAO Jie, iamcaojie@gmail.com moist atmosphere in which precipitation can occur; Bannon (2002) proposed a set of dynamic and thermodynamic equations for cloudy air.…”

Section: Introductionmentioning

confidence: 99%

A Brief Report of Graphic Explanations for Generalized Potential Temperature in the Non-Uniformly Saturated Atmosphere

Cao

Zhou

Gao

2011

Atmospheric and Oceanic Science Letters

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Compared to potential temperature () in the dry atmosphere and equivalent potential temperature ( e ) in the saturated atmosphere, generalized potential temperature ( * ) has already proven a better thermodynamic parameter in describing the non-uniformly saturated real atmosphere. To add otherwise absent graphic explanations, this paper first presents the physical definition of  * through a tephigram. Then, the utility of the measurement in identifying and forecasting the locations of precipitation maxima and heat wave areas with diagnostic comparison studies and traditionally used thermodynamic parameters is shown.  Keywords: generalized potential temperature, physical graph, thermodynamic parameters Citation: Cao, J., Y.-S. Zhou, and S.-T. Gao, 2011: A brief report of graphic explanations for generalized potential temperature in the non-uniformly saturated atmosphere, Atmos. Oceanic Sci. Lett., 4, 162-167.

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Entropy and Potential Temperature

Cited by 63 publications

References 0 publications

On the computation of moist‐air specific thermal enthalpy

On the computation of moist‐air specific thermal enthalpy

Using enthalpy as a prognostic variable in atmospheric modelling with variable composition

A Brief Report of Graphic Explanations for Generalized Potential Temperature in the Non-Uniformly Saturated Atmosphere

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