Siberian observing system for climate-change research as it has been formed by the moment and how it might be extended in the future

The carbon cycle of Siberia is a growing field of scientific research. The number of researchers focusing attention to this region has been constantly increasing during the last decade. This is a stable tendency stemming from the imbalance between the importance of this region for the climate system and the amount of relevant information available at the international level. The Siberian Observing System for Climate Change Research (SOS) has been designed to provide systematic, spatially and temporally detailed information on the gas fluxes from this remote, huge, and very important part of the Earth System. It started with an aircraft campaign in 1992 and over the next 10 years developed into a complex system of continuous observations. For promoting and ensuring sustained systematic observations, SOS must work closely with interested international organizations, regional and global research programs, and related research projects. The objective of this paper is to provide information about the key components of the SOS and call for joint efforts on completing their geographic and thematic coverage.