Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 15, 3565-3573, 2015
https://doi.org/10.5194/acp-15-3565-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
31 Mar 2015
Rapid transport of East Asian pollution to the deep tropics
M. J. Ashfold1,*, J. A. Pyle1,2, A. D. Robinson1, E. Meneguz3, M. S. M. Nadzir4,5,6, S. M. Phang6, A. A. Samah6, S. Ong7, H. E. Ung7, L. K. Peng8, S. E. Yong8, and N. R. P. Harris1 1Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
2NCAS, UK
3Met Office, FitzRoy Road, Exeter, EX1 3PB, UK
4School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
5Centre for Tropical Climate Change System (IKLIM), Institute for Climate Change, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
6Institute of Ocean and Earth Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
7Global Satria Life Sciences Lab, TB 12188, Taman Megajaya Phase 3, 91000 Tawau, Sabah, Malaysia
8Malaysian Meteorological Department (METMalaysia), Global Atmosphere Watch (GAW) Danum Valley, 91112 Lahad Datu, Sabah, Malaysia
*now at: School of Biosciences, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
Abstract. Anthropogenic emissions from East Asia have increased over recent decades. These increases have led to changes in atmospheric composition as far afield as North America under the prevailing westerly winds. Here we show that, during Northern Hemisphere (NH) winter, pollution originating in East Asia also directly affects atmospheric composition in the deep tropics. We present observations of marked intra-seasonal variability in the anthropogenic tracer perchloroethene (C2Cl4) collected at two locations in Borneo (117.84° E, 4.98° N and 118.00° E, 4.22° N) during the NH winter of 2008/2009. We use trajectories calculated with the Numerical Atmospheric-dispersion Modelling Environment to show that the observed enhancements in C2Cl4 mixing ratio are caused by rapid meridional transport, in the form of "cold surges", from the relatively polluted East Asian land mass. In these events air masses can move from ~35° N to Borneo in 4 days. We then present data from the Monitoring Atmospheric Composition and Climate reanalysis which suggest that air masses high in C2Cl4 may also contain levels of the pollutants carbon monoxide and ozone that are approximately double the typical "background" levels in Borneo. In addition to strengthening the meridional transport from the north, cold surges can enhance convection in Southeast Asia, and further trajectory calculations indicate that the polluted air masses can subsequently be lifted to the tropical upper troposphere. This suggests a potentially important connection between midlatitude pollution sources and the very low stratosphere.

Citation: Ashfold, M. J., Pyle, J. A., Robinson, A. D., Meneguz, E., Nadzir, M. S. M., Phang, S. M., Samah, A. A., Ong, S., Ung, H. E., Peng, L. K., Yong, S. E., and Harris, N. R. P.: Rapid transport of East Asian pollution to the deep tropics, Atmos. Chem. Phys., 15, 3565-3573, https://doi.org/10.5194/acp-15-3565-2015, 2015.
Publications Copernicus
Download
Short summary
We use observations and model calculations to show that "cold surges" occurring during Northern Hemisphere winter can rapidly transport East Asian pollution to equatorial Southeast Asia. As well as affecting atmospheric composition near the surface, we argue that strong convection can subsequently lift the polluted air masses to the tropical upper troposphere. This suggests a potentially important connection between midlatitude pollution sources and the lower stratosphere.
We use observations and model calculations to show that "cold surges" occurring during Northern...
Share