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| Titel |
Atmospheric boundary layer characteristics over the Pearl River Delta, China, during the summer of 2006: measurement and model results |
| VerfasserIn |
S. J. Fan, Q. Fan, W. Yu, X. Y. Luo, B. M. Wang, L. L. Song, K. L. Leong |
| 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. 13 ; Nr. 11, no. 13 (2011-07-04), S.6297-6310 |
| Datensatznummer |
250009887
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| Publikation (Nr.) |
 copernicus.org/acp-11-6297-2011.pdf |
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| Zusammenfassung |
| As part of the PRIDE-PRD2006 intensive campaign, atmospheric boundary layer
(ABL) measurements were performed in Qingyuan, Panyu, and Xinken over the
Pearl River Delta (PRD) on 1–30 July 2006. During the summer, the surface
winds over the PRD are generally controlled by the south, usually with
vertical wind shear at a height of approximately 800 m. Subsidence and
precipitation from a tropical cyclone affects the air quality of the PRD.
Under subsidence, wind speed in the ABL and the height of the ABL decrease
and result in high-level concentrations. When the background wind speed is
small or calm, the wind profile in Panyu and Xinken changes dramatically
with height, which is perhaps caused by local circulation, such as sea-land
breezes. To better understand the ABL of the PRD, simulations that used the
Weather Research and Forecasting (WRF) mesoscale model were utilized to
analyze the ABL characteristics over the PRD. Based on three types of
weather condition simulations (i.e., subsidence days, rainy days, and sunny
days), the WRF model revealed that the simulated temperature and wind fields
in these three cases were moderately consistent with the measurements. The
results showed that diurnal variations of the ABL height on subsidence days
and sunny days were obvious, but diurnal variations of the ABL height on
rainy days were not apparent. The ABL is obviously affected by local
circulation, and the ABL features are different at various stations. A
simulation focused on a high pollution episode during the subsidence days on
12–15 July 2006, occurred under high-pressure conditions, accompanied by the
tropical cyclone "Bilis". A comparison of the simulated vertical wind fields
and temperature structure with the ABL measurements at Xinken, Panyu, and
Qingyuan stations found that the modeled and measured atmospheric fields
revealed two different types of ABL characteristics over the PRD. When the
surface winds over the PRD were light or nearly calm, the local circulation
dominated, such as the sea-land breeze at Xinken station and the
mountain-valley circulation at Qingyuan station. When the surface winds were
strong, the stations were under the same background weather system, and the
wind directions were almost the same. Furthermore, the modeled results also
suggest that the subsidence by the typhoon "Bilis" had a great impact on the high
Air Pollution Index (API). |
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