Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 5.509 IF 5.509
  • IF 5-year value: 5.689 IF 5-year 5.689
  • CiteScore value: 5.44 CiteScore 5.44
  • SNIP value: 1.519 SNIP 1.519
  • SJR value: 3.032 SJR 3.032
  • IPP value: 5.37 IPP 5.37
  • h5-index value: 86 h5-index 86
  • Scimago H index value: 161 Scimago H index 161
Volume 17, issue 24 | Copyright
Atmos. Chem. Phys., 17, 15037-15043, 2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.

Technical note 19 Dec 2017

Technical note | 19 Dec 2017

Technical note: A noniterative approach to modelling moist thermodynamics

Nadya Moisseeva and Roland Stull Nadya Moisseeva and Roland Stull
  • Dept. of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2020-2207 Main Mall Vancouver, BC, V6T 1Z4, Canada

Abstract. Formulation of noniterative mathematical expressions for moist thermodynamics presents a challenge for both numerical and theoretical modellers. This technical note offers a simple and efficient tool for approximating two common thermodynamic relationships: temperature, T, at a given pressure, P, along a saturated adiabat, T(P, θw), as well as its corresponding inverse form θw(P, T), where θw is wet-bulb potential temperature. Our method allows direct calculation of T(P, θw) and θw(P, T) on a thermodynamic domain bounded by −70 ≤ θw < 40°C, P > 1kPa and −100 ≤ T < 40°C, P > 1kPa, respectively. The proposed parameterizations offer high accuracy (mean absolute errors of 0.016 and 0.002°C for T(P, θw) and θw(P, T), respectively) on a notably larger thermodynamic region than previously studied. The paper includes a method summary and a ready-to-use tool to aid atmospheric physicists in their practical applications.

Download & links
Publications Copernicus
Short summary
This technical note presents simple noniterative approximations for two common thermodynamic relationships used for moist convection. The method offers roughly 2 orders of magnitude improvement in accuracy over the only existing noniterative solution. The proposed approach alleviates the need for costly numerical integration of saturated thermodynamic equations within numerical weather prediction models and in theoretical studies.
This technical note presents simple noniterative approximations for two common thermodynamic...