This is the main project site of the GEO Air Quality Community of Practice Community WCS server (public access) and the Jülich WCS interface (restricted access). WCS is a standard for geospatial information exchange defined by the Open Geospatial Consortium ( WCS enables web applications to share time-varying geospatial data sets across different sites without having to keep local copies of these data. The GEO AQ CoP Community WCS server is a python tool that has been jointly developed by Washington University, Louisiana, USA (Rudy Husar and Kari Hoijvari) and Forschungszentrum Jülich (Michael Decker and Martin Schultz). It has been successfully implemented at a number of sites worldwide to deliver data from atmospheric composition measurement stations, satellites and numerical models (see the section on the “Air quality data network” on The Jülich WCS interface allows for easy access to data that are delivered from WCS servers and includes options to select geographic regions, variables, time ranges, and to visualize the data in various ways. It is for example employed in the European MACC project (Monitoring Atmospheric Composition and Climate) as a boundary condition server for regional air quality models (see , or as a front-end to the TFHTAP multi-model experiment database hosted at IEK-8 of Forschungszentrum Jülich (see