HR: 0800h
AN: A51D-0090    [Abstracts]
TI: Influence of Stratosphere-to-Troposphere Exchange on the Seasonal Cycle of Surface Ozone at Mt Waliguan in Western China
AU: * Ding, A
EM: cedingaj@polyu.edu.hk
AF: The Hong Kong Polytechnic University, Department of Civil & Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China, Hong Kong, China
AU: Wang, T
EM: cetwang@polyu.edu.hk
AF: The Hong Kong Polytechnic University, Department of Civil & Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China, Hong Kong, China
AB: Surface ozone over the Qinghai-Tibetan Plateau exhibits a maximum in summer contrasting to a spring peak observed in many remote locations of the Northern Hemisphere. In this study we performed mesoscale meteorological simulations for April-August 2003, when intensive measurement of trace gases was carried out at remote Mt Waliguan, in order to elucidate the influence of atmospheric dynamics on the high ozone events observed during the study and on the seasonal cycle. Examinations of potential vorticity, ozone (both surface and total column), and CO suggests that most of the synoptic-scale ozone enhancements, determined by using a scale separation technique, were due to intrusion of stratospheric air, as opposed to long-range transport of anthropogenic pollution. Case studies show that the existence of jet stream is the main dynamical cause for the downward transport of stratospheric air. Further analysis of upper-level mean zonal winds suggests that in Central Asia stronger subtropical jet streams in summertime (June-July) lead to more frequent stratospheric intrusions in summer compared to spring (March-April), which has contributed to higher surface ozone in summer at Mt Waliguan and other parts of Central Asia.
DE: 0368 Troposphere: constituent transport and chemistry
DE: 3329 Mesoscale meteorology
DE: 3362 Stratosphere/troposphere interactions
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005