Buoyancy statistics in moist turbulent Rayleigh-Benard convection

TL;DR

This paper investigates how phase changes in moist turbulent Rayleigh-Benard convection influence buoyancy fluctuations and transfer, providing insights relevant for atmospheric convection modeling.

Contribution

It introduces a numerical framework for analyzing moist convection with phase change effects, highlighting their impact on buoyancy and cloud formation.

Findings

Phase changes enhance buoyancy flux compared to dry convection.

Buoyancy transfer varies with Rayleigh number and moisture content.

The study offers a basis for improved atmospheric convection parametrizations.

Abstract

We study shallow moist Rayleigh-Benard convection in the Boussinesq approximation in three-dimensional direct numerical simulations. The thermodynamics of phase changes is approximated by a piecewise linear equation of state close to the phase boundary. The impact of phase changes on the turbulent fluctuations and the transfer of buoyancy through the layer is discussed as a function of the Rayleigh number and the ability to form liquid water. The enhanced buoyancy flux due to phase changes is compared with dry convection reference cases and related to the cloud cover in the convection layer. This study indicates that the moist Rayleigh-Benard problem offers a practical framework for the development and evaluation of parametrizations for atmospheric convection.