Increase of ozone concentrations, its temperature sensitivity and the precursor factor in South China
Increase of ozone concentrations, its temperature sensitivity and the precursor factor in South China
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DOI：
10.3402/tellusb.v66.23455
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发表时间：
2014-01-01
影响因子：
2.3
通讯作者：
Lai, C. S.
中科院分区：
文献类型：
--
作者：
Lee, Y. C.;Shindell, D. T.;Lai, C. S.
人们对当地和区域光化学问题与全球变暖之间可能存在的联系表示担忧。目前的研究评估了香港和华南珠三角地区的臭氧趋势，并研究了臭氧对气温敏感度的年际变化，以及区域前体的趋势。结果显示，从20世纪90年代中期到2010年，三个监测点的臭氧平均浓度从每年1.0μg.m(-3)增加到1.6μg.m(-3)。各季节均有增加，其中秋季增幅最高。这与该地区的趋势和温度异常一致。从 7 月至 9 月臭氧显着高期期间珠三角地区相关图中显示的臭氧（OMI [臭氧监测仪器]柱量）和地表空气温度（来自大气红外探测器）之间的相关性可以明显看出，臭氧对温度的敏感性增加。据观察，从 2005 年到 2010 年，气温有所增加，后者是全球有记录以来最热的一年。为了验证灵敏度的这种时间变化，分析了相关系数/回归斜率的地面趋势。正如预期的那样，结果显示在 14 年期间（1997 年至 2010 年）呈统计上显着的上升趋势。虽然相关图中显示的相关性与相应的 OMI 臭氧图并列时一致，但表面臭氧的温度敏感性也显示出与臭氧浓度的相关性，R = 0.5。据信，臭氧敏感性的这些特征对该地区具有不利影响。根据地面测量及/或卫星分析显示，香港的氮氧化物(NO2)及NOx的减少并无统计显着性，而珠三角的NO2则只有轻微的变化。然而，整个地区的二氧化碳含量显着下降。虽然这些关于前体的观察结果似乎不足以支持臭氧增加的趋势，但测量到的甲醛（挥发性有机化合物（VOC）排放量的代表）表面水平在珠三角（2004-2010年）显着上升。因此，就前体而言，珠三角地区的活性挥发性有机化合物很可能是臭氧增加的罪魁祸首。尽管存在普遍问题，但模型模拟表明了未来改进的前景。
Concerns have been raised about the possible connections between the local and regional photochemical problem and global warming. The current study assesses the trend of ozone in Hong Kong and the Pearl River Delta (PRD) in South China and investigates the interannual changes of sensitivity of ozone to air temperature, as well as the trends in regional precursors. Results reveal, at the three monitoring sites from the mid-1990s to 2010, an increase in the mean ozone concentrations from 1.0 to 1.6 mu g.m(-3) per year. The increase occurred in all seasons, with the highest rate in autumn. This is consistent with trends and temperature anomalies in the region. The increase in the sensitivity of ozone to temperature is clearly evident from the correlation between ozone (OMI [Ozone Monitoring Instrument] column amount) and surface air temperature (from the Atmospheric Infrared Sounder) displayed in the correlation maps for the PRD during the prominently high ozone period of July-September. It is observed to have increased from 2005 to 2010, the latter being the hottest year on record globally. To verify this temporal change in sensitivity, the ground-level trends of correlation coefficients/regression slopes are analysed. As expected, results reveal a statistically significant upward trend over a 14-year period (1997-2010). While the correlation revealed in the correlation maps is in agreement with the corresponding OMI ozone maps when juxtaposed, temperature sensitivity of surface ozone also shows an association with ozone concentration, with R = 0.5. These characteristics of ozone sensitivity are believed to have adverse implications for the region. As shown by ground measurements and/or satellite analyses, the decrease in nitrogen oxides (NO2) and NOx in Hong Kong is not statistically significant while NO2 of the PRD has only very slightly changed. However, carbon dioxide has remarkably declined in the whole region. While these observations concerning precursors do not seem to adequately support an increasing ozone trend, measured surface levels of formaldehyde, a proxy for volatile organic compound (VOC) emissions, have risen significantly in the PRD (2004-2010). Hence, the reactive VOCs in the PRD are likely to be the main culprit for the increase of ozone, as far as precursors are concerned. Despite the prevailing problem, model simulations suggest prospects for improvement in the future.