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| Titel |
Impact of the East Asian summer monsoon on long-term variations in the acidity of summer precipitation in Central China |
| VerfasserIn |
B. Z. Ge, Z. F. Wang, X. B. Xu, J. Tang, Y. J. He, I. Uno, T. Ohara |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 4 ; Nr. 11, no. 4 (2011-02-21), S.1671-1684 |
| Datensatznummer |
250009370
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| Publikation (Nr.) |
 copernicus.org/acp-11-1671-2011.pdf |
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| Zusammenfassung |
| The acidity of precipitation has been observed at
stations of the Acid Rain Monitoring Network run by the China Meteorological
Administration (CMA-ARMN) since 1992. Previous studies have shown that
different long-term trends exist in different regions but detailed analysis
of the causes of these is lacking. In this paper, we analyze summertime
precipitation acidity data from the CMA-ARMN during 1992–2006 using EOFs and
show that the summertime pH in China had different trends before and after
2000. The most significant decrease of pH is found in Central China. To
investigate the causes of this decrease of pH in summer, we explore the
relationship between changes in the pH value, the East Asian summer monsoon
index, rainfall data, and pollutants emissions. We find that the East Asian
summer monsoon can significantly affect the acidity of summer precipitation
in Central China. In strong monsoon years, the pH in Central China is about
0.33 lower than that in weak monsoon years. Chemical transport model
simulations using fixed emissions indicate that about 65% of the pH value
difference (i.e., 0.22) is related to the summer monsoon, and constitutes
18–36% of the observed pH change (0.6∼1.2) in Central China during
1992–2006. Further studies reveal a relationship between the pH in Central
China and the rainfall in the middle and lower reaches of the Yangtze River
(MLYR), which can explain about 24% of the variance of pH in Central
China. Simulations using an annually varying emission inventory show that at
least 60% of the variation in precipitation acidity in Central China can
be attributed to changes in pollutant emissions. Therefore, the increase in
emissions of acidic species is the most important cause for the observed
decrease of pH in Central China, and changes in meteorological factors, such
as rainfall and other parameters related to the East Asian summer monsoon,
play a less important but still significant role. |
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