Greenhouse gas budget at Japanese rice paddy as an AsiaFlux Network site

Observed data on greenhouse gases exchange between terrestrial ecosystems and the atmosphere are strongly demanded to conclude inter-governmental agreements on greenhouse gases emission in COP6 and further negotiations of draw up the concrete amounts. Agricultural fields are thought to be sources of CO2 as the annual budget and rice paddy is major CH4 source, but the actual budget have been measured at a few vegetation. We established AsiaFlux network sites in Japan, Korea and some other southeastern Asian countries to reveal the greenhouse gas and energy budgets at each ecosystem under the eastern Asian monsoon climate. The rice paddy is major agricultural ecosystem adapted to eastern Asia. We had tower flux observation at a rice paddy from 1993 to 1996 but were only during the rice growing seasons, however, the greenhouse gases budgets at agricultural ecosystem are strongly affected by the management manners of fields. Therefore we started continuous flux observational study as an activity of AsiaFlux network from 1999. In the paper, we introduce the outline of the AsiaFlux Network and some results from rice paddy site in central part of Japan with previous results.