GEWEX Cloud System Study - Working Group 4

This is the old WG4 web page. The last update was in January 2004. The new WG4 web page is at http://www.convection.info/

The current WG4 Chair is Jon Petch from UK MetOffice.

 

---- former Chair, Wojtek Grabowski

 

The goal of GCSS (GEWEX Cloud System Study) Working Group 4 (WG 4) is to improve the parameterization of precipitating convective cloud systems in global climate models (GCMs) and numerical weather prediction models through an improved physical understanding of cloud system processes. The main tool of GCSS WG 4 is the cloud-resolving model (CRM), which is a numerical model that resolves cloud-scale (and mesoscale) circulations in either two or three spatial dimensions. In contrast, a GCM cannot resolve the individual convective cells or even the accompanying mesoscale circulations. Therefore, in a GCM the collective effects of these sub-grid scale processes must be parameterized. A CRM is able to determine these collective effects directly, to the extent that its representation of grid-scale dynamics and the parameterizations of its own sub-grid processes are accurate.

GCSS Working Group 4 organizes model intercomparison projects. The results from these intercomparisons are presented at annual meetings and in publications. An e-mail list is maintained to disseminate information of interest to WG 4.

The model intercomparison activities are coordinated by a steering committee which selects specific studies and observational data with which to initialize and evaluate the CRMs, sets out strategies for analyzing the CRM results, organizes meetings, and is responsible for publishing scientific conclusions and key recommendations.

The 2002 WG4 Report describes GCSS WG 4 in more detail, and is available in PDF or HTML format.