ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-11-26441-2011 The impact of channel effect on Asian dust transport dynamics: a case in southeastern Asia Lin C.-Y. 1 Sheng Y.-F. 1 Chen W.-N. 1 Wang Z. 2 Kuo C.-H. 3 Chen W.-C. 1 Yang T. 2 Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan Institute of Atmospheric physics, Chinese Academy of Science, Beijing, China Department of Geology, Chinese Culture University, Taipei, Taiwan 22 09 2011 11 9 26441 26475 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/11/26441/2011/acpd-11-26441-2011.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/11/26441/2011/acpd-11-26441-2011.pdf

A super heavy dust event was identified with unprecedented PM<sub>10</sub> in terms of speed and concentration in the southeastern Asia. The average concentration was observed exceeding the value of 1000 μg m<sup>−3</sup> for the duration lasting more than 10 h, with the highest value reached 1724 μg m<sup>−3</sup> in northern Taiwan on 21 March 2010. We found that this case exhibited an uneven and intriguing spatial distribution of PM<sub>10</sub> concentration and transport speed between eastern and western Taiwan. Higher values were observed in the western and northern areas. The differences in concentration can be reached to 5 times in less than 100 km in the west-east bound distance while the variations can be up to 10 times within 400 km in north-south direction. A high resolution, 10 km, numerical study by Weather Research Forecast (WRF) and WRF-chem models revealed that this intriguing spatial distribution of the Asian dust transport was resulting from a strong coupling effect of the geographic channel effect and blocking of the easterly from the Pacific Ocean. We are confident that this coupling effect can be revealed only by applying a high resolution numerical study in other similar regions.

 References Boyle, J. S., and Chen, T.-J.: Synoptic aspects of the wintertime East Asian monsoon, in: Monsoon Meteorology, edited by: Chang, C. P. and Krishnamurti, T. N., 125–160, Oxford Univ. Press, New York, 1987. Chang, K. M.: Prediction of the strength of overnight easterly winds in Hong Kong in Winter, Hong Kong Observatory Technical Note No. 79, 1989. Chen, G. T. J. and Lin, K. C.: A diagnostic case study of a winter low-level front over southern China, Mon. Weather Rev., 127, 1096–1107, 1999. Chen, Y.-L. and Hui, N. B.-F.: Analysis of a shallow front during the Taiwan Area Mesoscale Experiment, Mon. Weather Rev., 118, 2649–2667, 1990. Chien, F. C. and Kuo, Y. H.: Topographic Effects on a Wintertime Cold Front in Taiwan, Mon. Weather Rev., 134, 3297–3316, 2006. Chen, W.-N., Chang, S.-Y., Chou, Charles, C.-K., Chen, Y.-W., and Chen, J.-P.: Study of relationship between water-soluble Ca$^2+$ and lidar depolarization ratio for spring aerosol in the boundary layer, Atmos. Environ., 41, 1440–1455, 2007. Chin, M., Rood, R. B., Lin, S.-J., Muller, J.-F., and Thompson, A. M.: Atmospheric sulfur cycle simulated in the global model GOCART: Model description and global properties, J. Geophys. Res., 105, 25671–24687, 2000. Chin, M., Ginoux, P., Kinne, S., Torres, O., Holben, B., Duncan, B. N., Martin, R. V., Logan, J. A., Higurashi, A., and Nakajima, T.: Tropospheric aerosol optical thickness from the GOCART model and comparisons with satellite and sunphotometer measurements, J. Atmos. Sci., 59, 461–483, 2002. Chun, Y., Kim, J., Choi, J. C., Boo, K. O., Oh, S. N., and Lee, M.: Characteristic number size distribution of aerosol during Asian dust period in Korea, Atmos. Environ., 35, 2715–2721, 2001. Draxler, R. R. and Hess, G. D.: An overview of the Hysplit-4 modeling system for trajectories, dispersion, deposition, Aust. Meteorol. Mag., 47, 295–308, 1998. Eguchi, K., Uno, I., Yumimoto, K., Takemura, T., Shimizu, A., Sugimoto, N., and Liu, Z.: Trans-pacific dust transport: integrated analysis of NASA/CALIPSO and a global aerosol transport model, Atmos. Chem. Phys., 9, 3137–3145, http://dx.doi.org/10.5194/acp-9-3137-2009doi:10.5194/acp-9-3137-2009, 2009. Fang, M., Zheng, M., Wang, F., Chim, K. S., and Kot, S. C.: The long range transport of aerosols from northern china to Hong Kong – a multi-technique study, Atmos. Environ., 33, 1803–1817, 1999. Gao, T., Su, L., Ma, Q., Li, H., Li, X., and Yu, X.: Climatic analyses on increasing dust storm frequency in the springs of 2000 and 2001 in Inner Mongolia, Int. J. Climatol., 23, 1743–1755, 2003. Grell, G. A., Steven, E. P., and Rainer, S.: Fully coupled "online"chemistry within the WRF model, Atmos. Environ., 39, 6957–6975, 2005. Hong, S.-Y. and Dudhia, J.: Testing of a new non-local boundary layer vertical diffusion scheme in numerical weather prediction applications, 16th Conference on Numerical Weather Prediction, Seattle, WA, 2003. Hunt, C. R. and Snyder, W. H.: Experiments on stably and neutrally stratified flow over a model three-dimensional hill, J. Fluid Mech., 96, 671–704, 1980. In, H. J. and Park, S. U.: The soil particle size dependent emission parameterization for an Asian dust (Yellow Sand) observed in Korea in April 2002, Atmos. Environ., 37, 4625–4636, 2003. Kanayama, S., Yabuki, S., Yanagisawa, F., and Motoyama, R.: The chemical and strontium isotope composition of atmospheric aerosols over Japan: the contribution of long-range-transported Asian dust (Kosa), Atmos. Environ., 36, 5159–5175, 2002. Kim, S.-W., Yoon, S.-C., Jefferson, A., Ogren, J. A., Dutton, E. G., Won, J.-G., Ghim, Y. S., Lee, B.-I., and Han, J.-S.: Aerosol optical, chemical and physical properties at Gosan, Korea during Asian dust and pollution episodes in 2001, Atmos. Environ., 39, 39–50, 2005. Lee, K. L. and Zhang, M.: A numerical study on the orographic effect on the cold surge in Southern China.Proceedings of the Second International Conference on East Asia and Western Pacific Meteorology and Climate, 7–10 Hong Kong, September 1992. Lee, Y. C. and Hills, P. R.: Cool season pollution episodes in Hong Kong, 1996–2002, Atmos. Environ., 37, 2927–2939, 2003. Lin, C.-Y. and Chen C-.S.: A study of orographic effects on mountain-generated precipitation systems under weak synoptic forcing, Meteorol. Atmos. Phys., 81, 1–25, 2002. Lin, C.-Y., Liu, S. C., Chou, C. C.-K, Liu, T. H., Lee, C.-T., Yuan, C.-S., Shiu, C.-J., and Young, C.-Y.: Long-Range Transport of Asian Dust and Air Pollutants to Taiwan , Terrestrial Atmos. Ocean. Sci., 15, 759–784, 2004. Lin, C.-Y., Liu, S. C., Chou, C. C.-K, Huang, S.-J., Liu, C.-M., Kuo, C.-H., and Young, C.-Y.: Long-range transport of aerosols and their impact on the air quality of Taiwan, Atmos. Environ., 39, 6066–6067, 2005. Lin, C.-Y., Wang, Z., Chen, W.-N., Chang, S.-Y., Chou, C. C. K., Sugimoto, N., and Zhao, X.: Long-range transport of Asian dust and air pollutants to Taiwan: observed evidence and model simulation, Atmos. Chem. Phys., 7, 423–434, http://dx.doi.org/10.5194/acp-7-423-2007doi:10.5194/acp-7-423-2007, 2007a. Lin, C.-Y., Wang, Z., Chou, C. C.-K, Chang, C.-C., and Liu, S. C.: A numerical study of an autumn high ozone episode over southwestern Taiwan, Atmos. Environ., 41, 3684–3701, http://dx.doi.org/10.1016/j.atmosenv.2006.12.050doi:10.1016/j.atmosenv.2006.12.050, 2007b. Lin, C. Y., Chang, C. C., Chan, C. Y., Kuo, C. H., Chen, W. C., Chu, D. A., and Liu, S. C.: Characteristic of springtime profiles and sources of ozone in the low troposphere over northern Taiwan, http://dx.doi.org/10.1016/j.atmosenv.2009.10.020doi:10.1016/j.atmosenv.2009.10.020, Atmos. Environ., 44, 182–193, 2010. Lin, C.-Y., Hsu, H.-M., Sheng, Y.-F., Kuo, C.-H., and Liou, Y.-A.: Mesoscale processes for super heavy rainfall of Typhoon Morakot (2009) over Southern Taiwan, Atmos. Chem. Phys., 11, 345–361, http://dx.doi.org/10.5194/acp-11-345-2011doi:10.5194/acp-11-345-2011, 2011. Liu, Z., Liu, D., Huang, J., Vaughan, M., Uno, I., Sugimoto, N., Kittaka, C., Trepte, C., Wang, Z., Hostetler, C., and Winker, D.: Airborne dust distributions over the Tibetan Plateau and surrounding areas derived from the first year of CALIPSO lidar observations, Atmos. Chem. Phys., 8, 5045–5060, http://dx.doi.org/10.5194/acp-8-5045-2008doi:10.5194/acp-8-5045-2008, 2008. Murayama, T., Okamoto, H., Kaneyasu, N., Kamataki, H., and Miura, K.: Application of lidar depolarization measurement in the atmospheric boundary layer: Effects of dust and sea-salt particles, J. Geophys. Res., 104, 31781–31792, 1999. Kim, S. W., Yoon, S. C.,Jefferson, A., Ogren, J. A., Dutton, E. G., Won, J. G., Ghim, Y. S., Lee, B. I., and Han, J. S.: Aerosol optical, chemical and physical properties at Gosan, Korea during Asian dust and pollution episodes in 2001, Atmos. Environ., 39, 29–50, 2005. Omar, A. H., Winker, D. M., Vaughan, M. A., Hu, Y., Trepte, C. R., Ferrare, R. A., Lee, K. P., Hostetler, C. A., Kittaka, C., Rogers, R. R., Kuehn, R. E., and Liu, Z.: The CALIPSO automated Aerosol classification and Lidar ratio selection algorithm, J. Atmos. Ocean. Tech., 26, 1994–2014, 2009. Sugimoto, N., Hara, Y., Shimizu, A., Yumimoto, K., Uno, I., and Nishikawa, M.: Comparison of Surface Observations and a Regional Dust Transport Model Assimilated with Lidar Network Data in Asian Dust Event of 29 March to 2 April 2007, SOLA, 7A (Special Edition), 13–16, 2011. Sun, J., Zhang, M., and Liu, T.: Spatial and temporal characteristics of dust storms in China and its surrounding regions, 1960–1999: Relations to source area and climate, J. Geophys. Res., 106, 10325–10333, 2001. Trier, S. B., Parsons, D. B., and Matejka, T. J.: Observations of a subtropical cold front in a region of complex terrain, Mon. Weather Rev., 118, 2449–2470, 1990. Uematsu, M., Yoshikawa, A., Muraki, H., Arao, K., and Uno, I.: Transport of mineral and anthropogenic aerosols during a Kosa event over East Asia, J. Geophys. Res., 107, 4059, http://dx.doi.org/10.1029/2001JD000333doi:10.1029/2001JD000333, 2002. Uno, I., Amano, H., Emori, S., Kinoshita, K., Matsui, I., and Sugimoto, N.: Trans-Pacific yellow sand transport observed in April 1998: A numerical simulation, J. Geophys. Res., 106, 18331–18344, 2001. Uno, I., Yumimoto, K., Shimizu, A., Hara, Y., Sugimoto, N., Wang, Z., Liu, Z., and Winker, D. M.: 3-D Structure of Asian Dust Transport revealed by CALIPSO Lidar and a 4DVAR Dust Model, Geophys. Res. Lett., 35, L06803, http://dx.doi.org/10.1029/2007GL032329doi:10.1029/2007GL032329, 2008. Uno, I., Eguchi, K., Yumimoto, K., Takemura, T., Shimizu, A., Uematsu, M., Liu, Z., Wang, Z., Hara, Y., and Sugimoto, N.: Asian dust transported one full circuit around the globe, Nature Geosci., 2, 557–560, 2009. Wai, K. M. and Tanner, P. A.: Relationship between ionic composition in PM$_10$ and the synoptic-scale and mesoscale weather conditions in a south China coastal city:A 4-year study, J. Geophys. Res., 110, D18210, http://dx.doi.org/10.1029/2004JD005385doi:10.1029/2004JD005385, 2005. Winker, D. M., Hunt, W. H., and McGill, M. J.: Initial performance assessment of CALIOP, Geophys. Res. Lett., 34, L19803, http://dx.doi.org/10.1029/2007GL030135doi:10.1029/2007GL030135, 2007. Yeh, H. C. and Chen, Y. L.: Characteristics of rainfall distributions over Taiwan during the Taiwan area mesoscale experiment (TAMEX), J. Appl. Meteor., 37, 1457–1469, 1998.