The GAW Quality Assurance/Scientific Activity Centre (QA/SAC Switzerland) was established at Empa in 2000 and is one of four such facilities worldwide. It is funded by MeteoSwiss and Empa to focus on surface ozone, carbon monoxide, methane and carbon dioxide measurements, but tries to be as broad in scope as possible.

The main tasks of QA/SAC Switzerland are

• To support and audit the quality control system at global GAW sites,
• To assist GAW sites with data quality issues and questions of data submission,
• To promote the use of GAW data,
• To support capacity building through training and workshops, to assist the GAW Secretariat with general operational issues.

Achievements
A continuous concern of QA/SAC Switzerland is the data quality of surface ozone, carbon monoxide and methane measurements at global GAW stations. Based on GAW Report No. 97 and international standards such as the Guide for the Expression of Uncertainty in Measurement (GUM), QA/SAC Switzerland has issued a report on Traceability, uncertainty and assessment criteria of surface ozone measurements.

QA/SAC Switzerland was involved in the preparation of various GAW reports such as GAW Report No. 142 (Strategy for the Implementation of the Global Atmosphere Watch Programme, 2001-2007), GAW Report No. 143 (Global Atmosphere Watch Measurements Guide), GAW Activity Report for WMO RA VI (1998-2002), as well as GAW Report No. 192 (Guidelines for the Measurement of Atmospheric Carbon Monoxide).

A major on-going activity is the development and operation of GAWSIS (GAW Station Information System), an interactive data base application to integrate information on the GAW measurement program. GAWSIS is designed to be both, an information pool for the entire GAW community as well as a management tool for the GAW Secretariat. Station characteristics, extensive meta data on available measurement dat and contact information are collected.

A big event for QA/SAC Switzerland was the Workshop on Status and Trends of GAW in WMO RA VI (Europe) that took place in Riga, Latvia, May 27-30, 2002. Some 75 participants gathered to discuss achievements, challenges and future directions of GAW activities in this area.

Further Information
Please direct questions and/or comments about EMPA’s GAW activities to Brigitte Buchmann (Head of section), Martin Steinbacher (QA/SAC Switzerland), or Christoph Zellweger (WCC-EMPA).