VARIATIONAL FEATURES OF PRECIPITATION DELTA-O-18 IN NORTHEAST QINGHAI-TIBET PLATEAU

There is a marked positive correlation between delta(18)O in atmospheric precipitation and temperature in the Northeast Qinghai-Tibet Plateau. The amount effect in Tuotuohe station is notable as the temperature is greater than or equal to 7.3 degrees C, so is in Xining as 8.3 degrees C. The analytic results show that the synoptic and climatic significant of different time scales is different, and their degrees are also different. Moreover, the relations between the weather systems in the Northeast Qinghai-Tibet Plateau and delta(18)O in precipitation are analyzed. Under the influence of continental air mass the delta(18)O change in the Plateau is synchronous with that of temperature and under the oceanic air mass originated from the Bengal Bay and the Arabian Sea there is a marked negative correlation between delta(18)O and precipitation amount or temperature in the monsoon region of the Plateau and also positive one between delta(18)O and temperature in the non-monsoon region.