Vertical Transportation Impact Studies, Shangri-la, And When The Male Near-surface Ozone

Ozone(O3) is one of the most important trace gases in the atmosphere. The main distribution of ozone is in stratosphere. Downward transport of stratospheric ozone through the stratosphere-troposphere exchange (STE) activity is one of inputs for tropospheric ozone. With the enhancement of anthropogenic activities, amount of ozone in the troposphere has been increasing since the 20th century. So it is significant to understand the contributions to surface ozone budget both from the transport process including the long range advections and downward vertical transport and tropospheric photochemical reactions.In this thesis, seasonal,monthly,and diurnal variations of surface ozone and their relationship with precursors(CO,NOx) from December,2007 to Novemeber,2009 at Shangri-La (SL), a regional GAW site which is located in Yunnan province, is analyzed. Meteorological data (wind, water vapor,etc) and empirically calculated height of boundary mixing layer along with backward trajectory model are applied to assess ozone behavior and the impact of downward vertical transports. A preliminary analysis of surface ozone observed at Dang Xiong (DX), the remote Tibet Province is also given out.Surface ozone at SL reaches the annual maximum in spring (especially in April),and the secondary maximum in winter. The minimum ozone concentration is in summer. CO and NOx at Shangri-La reach annual maximum in spring too, and the secondary maximum in summer. The minimum concentrations of CO and NOx are in winter and fall. Backward trajectories indicate that more frequency of air parcel transports from northwest and northeast directions and they have obviously influenced the higher ozone concentrations at SL both winter and spring.An index, Y, is designed and evaluated for identifying the downward vertical transport processes at SL.The index,Y positively correlates with the height of the backward trajectories air. A case of high Y values from July 5th to 10th,2008 is carefully analyzed,and the result suggests that very high ozone concentration is obviously attributed to the vertical transport triggred by a passage of west cold trough in the upper atmosphere which is associated with the STE.The total times of estimated downward vertical transports is 43 at SL including of 18 times in winter, and 5 times in summer. The maximal frequency of downward vertical transports may be a significant source of surface ozone in winter.Surface Ozone concentration at DX is 15-20 ppb lower than that at SL. Surface Ozone concentration also displays its high and low values respectively in winter-spring and summer. The relatively higher amount of 7Be,7Be/210Pb and ozone shows that the impact of downward vertical transports is more obvious during winter-spring here. A case of high surface ozone and CO during October 15th-20th,2009 is speculated to be associated with long range pollution transport which has passed over the Indian continent and the local convective upward transport aroused by the continuous sunshine weather conditions, although a high ridge in the upper atmosphere over the Tibet was not favorable for the occurance of STE downward transport.