The impacts of climate change on agrlcultural production in Tibet during the recent thirty years

Results from analysis of the dynamics of climatic resources during the recent 30 years in the main agricultural regions in Tibet showed that climatic warming mainly ocurred in winter and summer,especially in June．Accumulated temperature was increasing，and frostt-free period was shortening．Rainfall along the river and in Changdu was decreasing at the rate of 4～30mm per year，while in the south-east Tibet，annual rainfall gradually increased．Potential light-temperature productivity in 1980s was higher than those in 1960s and 1970s at increasing rate of 11～62kg／hm² annually during the recent thtee decades．For the potential climatic productivity，the higheat appeared in 1970s，and the lowest in 1980s．