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| Titel |
\textbf{Detailed Characteristics of Weekend Effects in Chinese Cities } Yong-Sang Choi, and Bo-Ram Kim Department of Environmental Science and Engineering, Ewha Womans University, Seoul 120-750 Korea |
| VerfasserIn |
Yong-Sang Choi, Bo-Ram Kim |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250045995
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| Zusammenfassung |
| In China, the weekend effects in climate variables and air pollutants have been found, and
many researchers studied characteristics of the weekend effect in various respects:
seasonality (Gong et al., 2006), regional variation (Choi et al., 2008), and long-term
change in its phase (Ho et al., 2009), etc. However, it is still equivocal that the
occurrence of the weekend effect is attributed to whether boundary anthropogenic
aerosol processes or semi-weekly synoptic weather system. This study investigates
the weekend effect in PM10 (aerosol particulate matter with a diameter < 10 μm)
mass concentrations, and its relationship with synoptic-scale weather variability in
Beijing and Tianjin. It was previously reported that Tianjin has stronger weekend
effect than Beijing (Choi et al., 2008), though their geolocations are very close so
that the cities are affected by the same atmospheric waves. Both cities have large
industrial complexes that emit large amount of air pollutants. For the analysis, we have
newly complied the air pollution index data from 2000 to 2009, obtained from the
State Environmental Protection Administration of China. We converted the row
values into the mass concentration anomalies from the 7-day mean. Any weeks with
missing data were removed. Using the anomalies can naturally remove seasonal cycle
and long-term trend of PM10 mass concentration. Our analysis is done for each
year and season due to transient phases of Chinese weekend effects. Fast Fourier
Transform is also used to extract 7-day frequency and amplitude of the anomalies
and its random orders. As a result, Beijing and Tianjin have a similar pattern of
weekend effects in summer, while it is not true in other seasons. Especially, the
characterized weekly pattern is most obvious in summer, 2002. We cannot show a
peak of spectrum nearby 0.14 (1/7day) operating FFT with artificial random orders,
implying that the weekend effect in the Chinese cities cannot occur by chance. This
study also shows the coupled weekly variations between PM10 concentrations
and the meteorological conditions: cloud, precipitation, surface wind, pressure,
etc. The significant coupling was observed in the boundary layer, but not in free
atmosphere. The results indicate that the generation of weekend effect is grounded on
boundary aerosol processes, but hardly on synoptic-scale weather variability. Therefore,
human activities more likely influence the weekend effects in some Chinese cities.
This study will present the abovementioned research results, together with detailed
characteristics of Chinese weekend effects that we have pursued since last few
years.
References
Choi, Y.-S., Ho, C.-H., Chen, D., Noh, Y.-H., Song, C.-K., 2008a. Spectral analysis of
weekly variation in PM10 mass concentration and meteorological conditions over China.
Atmospheric Environment 42,
655–666.
Gong. D.-Y., Guo, O., Ho, C.-H., 2006. Weekend effect in diurnal temperature range in
China : opposite signals between winter and summer. Journal of Geophysical Research 111,
D18113, doi:10.1029/2006JD007068.
Ho, C.-H., Y.-S., Choi, S.-K., Hur, 2009. Long-term changes in summer weekend effect
over northeastern China and the connection with regional warming. Geophys. Res. Lett., 36,
L15706, doi:10.1029/2009GL039509 |
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