10Be/7Be implies the contribution of stratosphere-troposphere transport to the winter-spring surface O3 variation observed on the Tibetan Plateau

10Be/7Be is a stratospheric sensitive tracer. In this paper, measurements of 10Be/7Be and surface O3 from October 2005 to May 2006 at Mt. Waliguan (hereafter WLG, 100.898°E, 39.287°N, 3810 m, a.s.l.), China global atmospheric watch (GAW) observatory, are introduced and used to investigate the stratosphere-troposphere transport (STT) and its impact on surface O3 on the Tibetan Plateau. The results show that the magnitude of STT is weak in winter, followed by strengthening from the end of winter to the middle of spring (from mid February to mid April) with large increases in 10Be,7Be,10Be/7Be and surface O3. At the end of spring (from the end of April to mid May in this paper), the STT weakened, and the continuous increase of surface O3 at WLG is produced by tropospheric photochemistry reactions.