Net water vapour exchange over a mixed needle and broad-leaved forest in Changbai Mountain during autumn

Water vapour and CO2fluxes were measured by the eddy-covariance technique above amixed needle and broad-leaved forest with affiliated meteorological measurements in ChangbaiMountain as part of China’s FLUX projects since late August in 2002. Net water vapour exchangeand environmental control over the forest were examined from September 1 to October 31 in 2002.To quantify the seasonal dynamics, the transition period was separated into leafed, leaf falling andleafless stages according to the development of leaf area. The results showed that(a) seasonalvariation of water vapour exchange was mainly controlled by net radiation (Rn) which could account