Abstract
Analysis of total ozone data measured at Taipei and Chengkung in Taiwan, suggests that the spatial variation of column ozone over Taiwan is negligible. Further analysis of the ozone sonding data over Taipei indicates that the seasonal variation of total ozone is strongly correlated to the change of stratospheric ozone and has a typical pattern of spring maximum and winter minimum. The tropospheric ozone occupies about 16% of the total column ozone, and has maximum levels in spring and summer. Intrusions of stratospheric ozone and meridional ozone transport by the Hadley circulation have resulted in higher ozone levels in the upper and mid-troposphere in spring. Photochemical ozone production in the boundary layer is crucial to the summer maximum. Column ozone below 2km height occupies about 3% of the total column and 18.6% of the troposphere ozone, which can be enhanced to 36% in July. Comparing this study's data with estimates from satellite data by Fishman et al. (1990), we note that there were changes of –3.3 %, -8.2 % and 34 % in the total, stratospheric and tropospheric ozone, respectively, from 1979-1987 to 1994 –1999. The tropospheric ozone-increasing trend is most noteworthy.
Highlights
Three factors are important to the distribution of tropospheric ozone (London and Liu 1992): downward transport of stratospheric ozone through tropopause folding (Roelofs and Lelieveld 1997), surface deposition and the photochemical production and loss. Levy et al (1997) use a Global Chemical Transport Model to reveal that two largest components in the Taiwan University, #1, section 4, Roosevelt Road, Taipei, TaiwanTAO, Vol 12, No 2, June 2001 global ozone budget are the stratospheric ozone injection and the surface dry deposition
Since Taipei and Chengkung are nearly along the same meridional line, but about 200km apart, the analysis suggests that total ozone over Taiwan region has a negligible spatial variation
Our analyses indicate that the mean total, stratospheric and tropospheric ozone is about 268, 225 and 43 D.U., respectively, during 1994-1999
Summary
Three factors are important to the distribution of tropospheric ozone (London and Liu 1992): downward transport of stratospheric ozone through tropopause folding (Roelofs and Lelieveld 1997), surface deposition and the photochemical production and loss. Levy et al (1997) use a Global Chemical Transport Model to reveal that two largest components in the. Chan et al (1998) analyze ozone sanding data at Hong Kong and reveal tropospheric ozone maximum in spring and minimum in summer They have attrib uted the later phenomenon to summer monsoon, which carries tropical clean air mass to this region. In Taiwan, monitoring of total ozone can be traced back to the 1960s, but it was not until 1992, when two Brewer Spectrometers were set up at two separate sites, that the inter-com pared datasets started to provide reliable information about local column ozone (Liu et al 1995). These sites are at Taipei (25°N, 121.3°E, 20m) and Chengkung (23.1°N, 12 1.4°E, 22m), approximately 200km apart along the same meridional line. Sparse temporal coverage of ozone sondings prevents us from doing any trend analysis; but still a composite analysis of daily variation is useful to enhance our understanding about the ozone behavior over East Asian region
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
