 |
| Titel |
Influence of air mass downward transport on the variability of surface ozone at Xianggelila Regional Atmosphere Background Station, southwest China |
| VerfasserIn |
J. Ma, W. L. Lin, X. D. Zheng, X. B. Xu, Z. Li, L. L. Yang |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 11 ; Nr. 14, no. 11 (2014-06-02), S.5311-5325 |
| Datensatznummer |
250118761
|
| Publikation (Nr.) |
 copernicus.org/acp-14-5311-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| In situ measurements of ozone (O3), carbon monoxide (CO) and
meteorological parameters were made from December 2007 to November 2009 at
the Xianggelila Regional Atmosphere Background Station (28.006° N,
99.726° E; 3580 m a.s.l.), southwest China. It was found that
both O3 and CO peaked in spring while the minima of O3 and CO
occurred in summer and winter, respectively. A normalized indicator (marked
as "Y") on the basis of the monthly normalized O3, CO and water vapor,
is proposed to evaluate the occurrence of O3 downward transport from
the upper, O3-rich atmosphere. This composite indicator has the
advantage of being less influenced by the seasonal or occasional variations
of individual factors. It is shown that the most frequent and effective
transport occurred in winter (accounting for 39% of the cases on the basis of
a threshold of the Y value larger than 4) and they can make a significant
contribution to surface O3 at Xianggelila. A 9.6 ppb increase
(21.0%) of surface ozone is estimated based on the impact of deep
downward transport events in winter. A case of strong O3 downward
transport event under the synoptic condition of a deep westerly trough is
studied by the combination of the Y indicator, potential vorticity, total
column ozone and trajectory analysis. Asian monsoon plays an important role
in suppressing O3 accumulation in summer and fall. The seasonal
variation of O3 downward transport, as suggested by the Y indicator at
Xianggelila, is consistent with the seasonality of
stratosphere-to-troposphere transport and the subtropical jet stream over
the Tibetan Plateau. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|