BASE-LINE SURFACE RADIATION NETWORK (BSRN WCRP) - NEW PRECISION RADIOMETRY FOR CLIMATE RESEARCH/

To support climate research, the World Climate Research Programme (WCR P) initiated a new radiometric network, the Baseline Surface Radiation Network (BSRN). The network aims at providing validation material for satellite radiometry and climate models. It further aims at detecting long-term variations in irradiances at the earth's surface, which are believed to play an important role in climate change. The network and its instrumentation are designed 1) to cover major climate zones, 2) to provide the accuracy required to meet the objectives, and 3) to ens ure homogenized standards for a long period in the future. The limits of the accuracy are defined to reach these goals. The suitable instrum ents and instrumentations have been determined and the methods for obs ervations and data management have been agreed on at all stations. Mea surements of irradiances are at 1 Hz, and the 1-min statistics (mean, standard deviation, and extreme values) with quality flags are stored at a centralized data archive at the WCRP's World Radiation Monitoring Center (WRMC) in Zurich, Switzerland. The data are quality controlled both at stations and at the WRMC. The original 1-min irradiance stati stics will be stored at the WRMC for 10 years, while hourly mean value s will be transferred to the World Radiation Data Center in St. Peters burg, Russia. The BSRN, consisting of 15 stations, covers the earth's surface from 80 degrees N to 90 degrees S, and will soon be joined by seven more stations. The data are available to scientific communities in various ways depending on the communication environment of the user s. The present article discusses the scientific base, organizational a nd technical aspects of the network, and data retrieval methods; shows various application possibilities; and presents the future tasks to b e accomplished.