1National Institute for Environmental Studies, Tsukuba 305–8506, Japan
2Graduate School of Science and Engineering, Ibaraki University, Mito, Ibaraki 310-8512, Japan
3Faculty of Science, Ibaraki University, Mito, Ibaraki 310–8512, Japan
*now at: Department of Chemical Engineering, Tokyo University of Agriculture and technology, 184–8588, Japan
Received: 11 May 2011 – Discussion started: 23 May 2011
Abstract. Pollution events extracted from the in situ observations of atmospheric CO2 and O2 mixing ratios at Hateruma Island (HAT, 24° N, 124° E) during the period from October 2006 and December 2008 are examined. The air mass origins for the pollution events are categorized by using back trajectory analysis, and the oxidative ratios (OR = −O2:CO2 molar exchange ratio) for selected pollution events are calculated. We find that there is a significant difference in the average oxidative ratios between events from China (OR = 1.14 ± 0.12, n = 25) and Japan/Korea (OR = 1.37 ± 0.15, n = 16). These values are in a good agreement with the national average oxidative ratios for the emissions from fossil fuel burning and cement production (FFBC) in China (ORFFBC = 1.11 ± 0.03) and Korea/Japan (ORFFBC = 1.36 ± 0.02). Compared with the observation, simulations of the atmospheric O2 and CO2 mixing ratios using Lagrangian particle dispersion models do a good job in reconstructing the average oxidative ratio of the pollution events originating in China but tend to underestimate for events originating in Japan/Korea. A sensitivity test suggests that the simulated atmospheric oxidative ratios at HAT are especially sensitive to changes in Chinese fuel mix.
Revised: 02 Feb 2012 – Accepted: 06 Feb 2012 – Published: 14 Mar 2012
Minejima, C., Kubo, M., Tohjima, Y., Yamagishi, H., Koyama, Y., Maksyutov, S., Kita, K., and Mukai, H.: Analysis of ΔO2/ΔCO2 ratios for the pollution events observed at Hateruma Island, Japan, Atmos. Chem. Phys., 12, 2713-2723, doi:10.5194/acp-12-2713-2012, 2012.