SAGE III was successfully launched on 10. Dec. 2001 on a Russian M3 rocket. It provides accurate data of aerosols, water vapour, ozone, and other key parameters of the earth's atmosphere. The science team of the SAGE III experiment at NASA has nominated the Koldewey-Station as an anchor site to contribute within the Data Validation Plan as part of the Operational Surface Networks. Data directly relevant to the SAGE III validation are aerosol measurements by photometers and lidar, as well as temperature measurements and ozone profiling by balloon borne sondes, lidar and microwave radiometer. Data will be provided quasi online for immediate validation tasks.