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URN: urn:nbn:de:swb:90-646603

Mixing layer height and its implications for air pollution over Beijing, China

Tang, Guiqian; Zhang, Jinqiang; Zhu, Xiaowan; Song, Tao; Muenkel, Christoph; Hu, Bo; Schaefer, Klaus; Liu, Zirui; Zhang, Junke; Wang, Lili; Xin, Jinyuan; Suppan, Peter; Wang, Yuesi

Abstract:
The mixing layer is an important meteorological factor that affects air pollution. In this study, the atmospheric mixing layer height (MLH) was observed in Beijing from July 2009 to December 2012 using a ceilometer. By comparison with radiosonde data, we found that the ceilometer underestimates the MLH under conditions of neutral stratification caused by strong winds, whereas it overestimates the MLH when sand-dust is crossing. Using meteorological, PM$_{2.5}$, and PM$_{10}$ observational data, we screened the observed MLH automatically; the ceilometer observations were fairly consistent with the radiosondes, with a correlation coefficient greater than 0.9. Further analysis indicated that the MLH is low in autumn and winter and high in spring and summer in Beijing. There is a significant correlation between the sensible heat flux and MLH, and the diurnal cycle of the MLH in summer is also affected by the circulation of mountainous plain winds. Using visibility as an index to classify the degree of air pollution, we found that the variation in the sensible heat and buoyancy term in turbulent kinetic energy (TKE) is insignificant when ... mehr


Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung - Atmosphärische Umweltforschung (IMK-IFU)
Publikationstyp Zeitschriftenaufsatz
Jahr 2016
Sprache Englisch
Identifikator ISSN: 1680-7316, 1680-7324
KITopen ID: 1000064660
HGF-Programm 12.02.04; LK 01
Erschienen in Atmospheric chemistry and physics
Band 16
Heft 4
Seiten 2459-2475
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