A New Cloud Microphysics Parameterization Including the Effects of Turbulence and Drop-size Distribution Based on the Lagrangian Cloud Model and its Application to the Large Eddy Simulation of Warm Clouds
Abstract
A microphysics parameterization of warm clouds are developed by analyzing the Lagrangian cloud model (LCM) (Noh et al. 2018). The basic formulae of autoconversion and accretion in the new parameterization follows Tripoli and Cotton (1980), but the proportional coefficients and threshold radius vary depending on the dissipation rate ɛ and the standard deviation of DSD σ. The parameterization is applied to the large eddy simulation (LES) of two different type of clouds; shallow cumulus clouds and stratocumulus clouds. For the application of the parameterization a novel method is developed to predict the variations of ɛ and σ within the cloud, while considering the dependence on the cloud type. The LES results with the LCM and with the new microphysics parameterization are compared, focusing on the precipitation process. The empirical coefficients in the parameterization are optimized based on the comparison with the LCM results. Furthermore, the sensitivity to ɛ and σ in the parameterization is investigated. The LES with several other cloud microphysics schemes are also compared to examine the performance of the parameterization.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A13L2610O
- Keywords:
-
- 3310 Clouds and cloud feedbacks;
- ATMOSPHERIC PROCESSESDE: 3311 Clouds and aerosols;
- ATMOSPHERIC PROCESSESDE: 3337 Global climate models;
- ATMOSPHERIC PROCESSESDE: 3354 Precipitation;
- ATMOSPHERIC PROCESSES