CLUBB (Cloud Layers Unified By Binormals) is a parameterization of turbulence and cloud processes in the Earth’s atmosphere.  It is a 1D model that predicts the evolution of fields as a function of altitude but not horizontal position.  It may be run as a standalone single-column model, or it may be implemented as a subgrid parameterization in a large-scale weather forecast or general circulation model. 

CLUBB is a unified parameterization.  It uses a single algorithm to model many cloud types, such as cumulus, stratocumulus, cumulus-rising-into-stratocumulus, and Arctic clouds.  In addition, it models clear convective boundary layers and stably stratified boundary layers, and it is being generalized to handle altostratocumulus clouds and deep convective clouds.

CLUBB is based on the assumed PDF method.  It strives to predict the subgrid-scale probability density function (PDF) of moisture, heat content, and turbulence within each grid box and for each model timestep.  This PDF can be used to diagnose useful quantities such as cloud fraction and liquid water content.  

CLUBB is being co-developed by researchers at University of Wisconsin — Milwaukee and researchers elsewhere.  CLUBB’s source code is available for download at

References:  Golaz et al. (2002); Larson et al. (2002); Larson and Golaz (2005)