Keywords:ozone, satellite, model simulation, pollution
The lower tropospheric ozone enhancement over Central and Eastern China (CEC) was reported by Hayashida et al. (2015) by using the Ozone Monitoring Instrument (OMI) multiple-layer product retrieved by Liu et al. (2010). However, to clarify the enhancement in the concentration of the lowermost ozone using spaceborne measurements, it is necessary to understand the effect of ozone variation in the upper troposphere and lower stratosphere (UT/LS) because of large smoothing errors in the retrieval scheme. In this study, a scheme was developed to eliminate the artificial effect of UT/LS ozone enhancement on lower tropospheric ozone retrieval using OMI. By applying the UT/LS screening scheme for June 2006, we removed the effect of the UT/LS ozone enhancement on the artificial effect on the lower tropospheric ozone. Even after UT/LS screening, we were able to show a clear enhancement in the lower tropospheric ozone over CEC in June 2006 and confirmed the conclusion derived by Hayashida et al. (2015). After screening the UT/LS effect, we compared satellite measurements with model simulations for O3 by using MRI-CCM2 (Deushi and Shibata, 2011). The observed O3 enhancement over CEC in June 2006 was reproduced very well by the model simulations. The effects of emissions from the open crop residue burning (OCRB) in the North China Plain on lower tropospheric ozone were also examined by utilizing the emission inventory developled by K. Yamaji (Yamaji et al., 2010). In the scale of the vertical resolution of OMI observation, the difference between the O3 with and without the OCRB effect was not very large (about 1 DU).
This study is a collaborative work with Dr. Xiong Liu, Harvard University. S. Hayashida was supported by a Grant-in-Aid from the Green Network of Excellence, Environmental Information (GRENE-ei) program, MEXT, Japan. We express our gratitude to Ms. Satoko Kayaba and Dr. Akiko Ono for their help with the data analysis.
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Hayashida S, et al. (2015): ACP, 15:9865-9881. doi:10.5194/acp-15-9865-2015
Liu X, et al.(2010): ACP, 10 (5):2521-2537. doi:10.5194/acp-10-2521-2010
Yamaji K et al. (2010): ACP, 10 (15):7353-7368.doi:10.5194/acp-10-7353-2010