Investigating the response of East Asian ozone to Chinese emission changes using a linear approach
- 作者：Kazuyo Yamajia ; kazuyo@jamstec.go.jp ; Itsushi Unob ; uno@riam.kyushu-u.ac.jp ; Hitoshi Iriea ; irie@jamstec.go.jp
- 关键词：Tropospheric O3 ; NO2 tropospheric vertical column density ; O3 chemistry ; East Asian-scale transport
- 刊名：Atmospheric Environment
- 出版年：2012
- 期刊代码：11_13522310
- 类别：env
- 出版时间：August, 2012
- 卷：55
- 期：Complete
- 页码：475-482
- 文件大小：1060 K
摘要
To illuminate the issue of trans-boundary O3 pollution and regional O3 reduction policies in East Asia, we have investigated the East Asian ozone (O3) response to perturbations caused by Chinese anthropogenic emissions using the Community Multiscale Air Quality (CMAQ) model, a regional chemical transport model. The O3 responses have been examined for the range between聽鈭?00 and聽+100%changes from the Chinese emissions level in 2004 in 10%intervals. We have found that springtime and summertime O3 responses both at the source and at the downwind areas can be regarded as linear over the range between聽鈭?0 and聽+100%changes from the current emissions level. We therefore suggest that the perturbation between聽鈭?0 and聽+100%is sufficiently small to avoid nonlinear chemical influence on O3 formation in a model experiment to investigate East Asian scale O3 source-receptor relationships. On the other hand, the O3 response is strongly nonlinear in April at Hong Kong, where the current NMVOCs/NOx ratio is low and the O3 production regime is easily moved to the NMVOCs sensitive region. The O3 responses to the NOx emission changes have been investigated using surface O3 concentrations at remote Japanese sites and tropospheric NO2 vertical column density (NO2 VCD) over central east China both with observations and with model simulations in springtime during 2003-2009. Analysis of satellite data shows that the observed range of NO2 VCD over central east China in 2003-2009 is the range between聽鈭?5 and聽+34%from the 2004 level, which corresponds approximately to an emission variation between聽鈭?1 and聽+29%. The O3 concentration in the downwind region during 2003-2009 responds linearly to a change of the NO2 VCD over central east China both in the model and in the observation. The corresponding O3 responses derived from surface observations at remote Japanese sites show linear features consistent with this expectation. The doubling of emissions, i.e., approximately 1.9-fold increase in the NO2 VCD from 2004, leads to O3 increments of 5 ppbv and 8 ppbv in the model and in the observation, respectively. The modeled O3 increase due to changes in NOx emission explains approximately 60%of the observed O3 trend at remote Japanese sites. Thus, approximately 40%of the observed O3 increase is unaccounted for by the NOx emissions growth.