GEWEX Cloud System Study (GCSS)

MEETING ANNOUNCEMENT
4TH PAN-GCSS MEETING -- 2-6 June 2008 -- Toulouse, France

The 4th Pan-GCSS Meeting on "Advances on Modelling and Observing Clouds and Convection" will be held 2-6 June 2008 at Meteo-France, Toulouse France. Further information on topics and a list of confirmed key-note speakers can be found on the meeting web site at: http://www.knmi.nl/~siebesma/PAN-GCSS/

The Call for Papers and subscription to the meeting is open now (see website: http://www.knmi.nl/~siebesma/PAN-GCSS/ ) and will be closed 1 March 2008.

GCSS Background

There are a variety of cloud processes that affect the large-scale behavior of the climate system, but occur on scales too small to be represented explicity in global numerical models used for climate and weather prediction. Scientists develop numerical representations or parameterizations to represent the behavior of these processes. It is generally recognized that inadequate parameterization of clouds is one of the greatest sources of uncertainty in the prediction of weather and climate.

GCSS is developing better parameterizations of cloud systems for climate models by improving our understanding of the physical processes at work within the following types of cloud systems: (1) boundary layer, (2) cirrus, (3) extra tropical layer, (4) precipitating convective, and (5) polar.  There are five GCSS working groups, one for each type of cloud system. Each of these working groups has adopted single-column modeling as a key research strategy, and each is also making use of cloud ensemble models.

The GCSS working groups are performing the following activities:

• Identifing and developing cloud-resolving and mesoscale models appropriate for each cloud system type.
• Specifing blueprints of minimum observational requirements for the development and validation of these models.
• Assembling, for particular cloud types, case-study data sets accessible to the community of (a) matched observations from satellites, surface and aircraft, and (b) mode-derived synthetic data sets.
• Conducting workshops, including model intercomparisions using the above case study data sets.
• Using the data sets to derive a better understanding of the coupled processes within different types of cloud systems and to derive improved parameterization schemes for large-scale models.

GCSS Objectives

• Develop the scientific basis for the parameterization of cloud processes.
• Highlight key issues and encourage other relevant programs to address them.
• Promote the evaluation and intercomparision of parameterization schemes for cloud processes.

Data Integration for Model Evaluation (DIME)

An Ad Hoc activitity called DIME has the goal to provide "test kits" for model evaluation based on the GCSS Model Intercomparison Projects, including detailed results from the participating Cloud Resolving Models.  William Rossow, NASA, GISS, is the chairperson.

Chair, GCSS

Dr. Pier Siebesma
Royal Netherlands Meteorological Institute
The Netherlands

GCSS Documents

3RD PAN-GCSS Meeting on Clouds, Climate and Models, Athens, Greece, 16-20 May 2005. Click here for the meeting report

The Second Science and Implementation Plan for the GEWEX Cloud System Study (GCSS) is available in PDF format.