HR: 0800h
AN: A51C-0783    [Abstracts]
TI: The characteristics for the seasonal variation of tropospheric ozone from ozonesounding measurements over Pohang, Korea
AU: * Lee, H
EM: hyunjin@pusan.ac.kr
AF: Pusan National University, Pusan National University 30 Jangjeon-dong, Geumjeong-gu, Busan, 609-735 Korea, Republic of
AU: Kim, J
EM: jaekim@pusan.ac.kr
AF: Pusan National University, Pusan National University 30 Jangjeon-dong, Geumjeong-gu, Busan, 609-735 Korea, Republic of
AB: This study presents the first analysis of vertical ozone sounding measurements over Pohang, Korea. The main focus is to analyze the seasonal variation of vertical ozone profiles and find what controls the ozone seasonality. The maximum ozone at surface and in the free troposphere is observed in May and June, respectively. In comparison with ozone seasonality at Oki (near sea level) and Happo (altitude of 1840m) in Japan, which are located at the same latitude as of Pohang, we have found that the month occurring ozone maximum at Japanese sites is always a month earlier than that at Pohang. The analysis of wind flow at surface shows wind shift from westerly to southerly in May over Japan, but in June over Pohang. However, this wind shifts above boundary layer occurs a month later. This wind shift results in decreasing significant amounts of ozone because southerly wind brings clean wet tropical air. It has been suggested that spring ozone maximum in the low troposphere is due to polluted air transporting from China. However, enhance ozone amounts over free troposphere in June appears to have different origin. The feature of tongue-like structure in time-height cross-section of ozone concentrations, which starts from the stratosphere and extends to the middle troposphere, suggests that the ozone enhancement occurs due to gradually migration of ozone from the stratosphere. High frequency of dry air with elevated ozone concentrations in the upper troposphere in June suggests that the air is transported from the stratosphere. The HYSPLIT trajectory analysis supports that enhanced ozone in the free troposphere is not likely due to transport from the source of anthropogenic activity.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting