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JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 111,
D14104,
doi:10.1029/2005JD006837,
2006
Investigation of enhanced cross-city transport and trapping of air pollutants by coastal and urban land-sea breeze circulations
Jeff C. F. Lo
Atmospheric, Marine and Coastal Environment Program, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon,
Hong Kong
Alexis K. H. Lau
Environmental Central Facility, Institute for the Environment, Hong Kong University of Science and Technology, Clear Water
Bay, Kowloon, Hong Kong
Jimmy C. H. Fung
Department of Mathematics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
Fei Chen
National Center for Atmospheric Research, Boulder, Colorado, USA
Abstract
Recent satellite observations show that a layer of haze perpetually hangs over the Pearl River Delta (PRD) region and surface
observations show numerous violations of the Hong Kong Air Quality Objective. This layer of haze mostly concentrates in the
Pearl River Estuary and a narrow (20 km wide) band along the shoreline, in particular during weak wind situations. Although
researchers suspect the land-sea breeze (LSB) circulations “concentrate” or “trap” various pollutants in this region, the
physical mechanism of the phenomenon has never been fully explained or quantified. In this paper, a mesoscale atmospheric
model (MM5) coupled with the Noah land surface model (LSM), which has bulk urban land use treatments along with a detailed
Pearl River Delta land use map, is used to investigate the unique feature and mechanism of this land-sea breeze effect and
the temporal evolution. A three-dimensional particle trajectory model is used to understand its associated pollutant transport,
trapping and accumulation. A conceptual model is then developed for the perpetual air pollution phenomenon in the region.
Further sensitivity experiments are used to illustrate the impact of urbanization and large-scale winds on the pollution processes.
Results show that urbanization enhances the pollutant trapping and therefore contributes to the overall poor air quality in
the region.
Received 30
October
2005;
accepted 17
April
2006;
published 22
July
2006.
Keywords: land-sea breeze circulation;
urbanization effect;
pollutant trapping.
Index Terms: 0345 Atmospheric Composition and Structure: Pollution: urban and regional (0305, 0478, 4251); 3307 Atmospheric Processes: Boundary layer processes; 3322 Atmospheric Processes: Land/atmosphere interactions (1218, 1631, 1843); 3329 Atmospheric Processes: Mesoscale meteorology; 3339 Atmospheric Processes: Ocean/atmosphere interactions (0312, 4504).
Read Full Article (file size: 7544497 bytes) Cited by
Citation: Lo, J. C. F., A. K. H. Lau, J. C. H. Fung, and F. Chen
(2006),
Investigation of enhanced cross-city transport and trapping of air pollutants by coastal and urban land-sea breeze circulations,
J. Geophys. Res.,
111,
D14104,
doi:10.1029/2005JD006837.
Copyright 2006 by the American Geophysical Union.
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