Transport of north China air pollution by midlatitude cyclones: Case study of aircraft measurements in summer 2007

Aijun Ding, Tao Wang, Likun Xue, Jian Gao, Andreas Stohl, Hengchi Lei, Dezhen Jin, Yu Ren, Xuezhong Wang, Xiaolin Wei, Yanbin Qi, Jian Liu, Xiaoqing Zhang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

84 Citations (Scopus)

Abstract

Warm conveyor belts (WCBs) and frontal activity play important roles in the longrange transport of air pollutants by lifting them from the planetary boundary layer (PBL) into the free troposphere (FT) in midlatitudes. In summer 2007, an aircraft study was carried out in northeast (NE) China in order to understand the role of midlatitude cyclones in air pollution transport in north and east China in warm seasons. During a flight on 27 June, high concentrations of ozone and related trace gases were observed, with maximum concentrations (O3 ∼ 140 ppbv, SO2 ∼ 14.6 ppbv, CO ∼ 1185 ppbv) recorded at an altitude of 2.6 km. In this paper we present a detailed analysis of this flight. The mesoscale meteorological model Weather Research and Forecasting (WRF) and a Lagrangian dispersion model called FLEXPART were used to aid the diagnostic analysis of the atmospheric dynamic structure and the understanding of the transport characteristics of regional and local air pollution. The flight took place in a region adjacent to a warm front associated with a weak cyclone in north China. The aircraft sampled both the WCB and warm air frontal zone of the cyclone. The simulations show that the observed high air pollution in the FT mostly originated from the North China Plain, especially the megacities Beijing and Tianjin. Their plumes were vented by a stagnant front, probably through, in part, topographic lifting by the mountains in the north, and then were quickly transported in the FT to the study region. Trajectory analysis and satellite data suggest that the observed air masses were further lifted by the WCB into the middle and upper troposphere and were exported from Asia toward North America and the Arctic.
Original languageEnglish
Article numberD08304
JournalJournal of Geophysical Research Atmospheres
Volume114
Issue number8
DOIs
Publication statusPublished - 27 Apr 2009

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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