| 北京地区臭氧时空分布特征的飞机探测研究 |
| 摘要点击 2929 全文点击 1766 投稿时间：2012-02-13 修订日期：2012-04-13 |
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| 中文关键词 臭氧 氮氧化物 大气边界层 空间分布 飞机探测 |
| 英文关键词 ozone nitrogen oxides atmospheric boundary layer spatial distribution aircraft sounding |
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| 中文摘要 |
| 利用2007~2010年北京地区上空(0~3.5 km)飞机探测的臭氧(O3)及氮氧化物(NO、NO2)等数据资料,分析O3的时空分布特征. 结果表明:①O3月平均体积分数随高度变化趋势有较好的一致性,随高度增加,均出现先增大后减小,然后稳定不变的趋势,且高空有一个比较明显的分界线(约1.5 km). 1.5 km 以下是O3体积分数垂直梯度变化较大的层次,均存在一个O3体积分数高值区,说明其受近地面人为活动的影响较大; 在1.5 km 以上,O3体积分数的垂直梯度变化明显减小,此空间处于混合层以上,气团运动受下垫面影响较小,输送作用可能对污染物体积分数的影响更加显著. ②O3体积分数变化具有明显的季节特征,春秋季节O3体积分数较低,夏季O3体积分数较高. 统计的月份中,只有7~9月之间O3均值变化最不明显,差异未达显著水平(P>0.05),其他月份之间均在0.01水平上差异显著. ③在夏季一天(白天)当中,每小时O3体积分数垂直廓线与月平均统计的变化趋势一致. 低空1.5 km以下O3体积分数的低值出现在上午(09:00~10:00)时段,高值出现在下午(15:00~16:00)时段,同高度内O3体积分数不同时段相差最大约为60×10-9; 高空1.5~3.5 km 内,O3体积分数相差不大,一般在70×10-9~80×10-9之间波动. ④O3体积分数水平区域分布,0~2 km内城区四环O3体积分数较高,周边地区也出现较多明显的高值区,源强汇低造成北京市区周边近地层O3体积分数较高; 高空2~4 km 内,除了北京城区O3体积分数较高外,城区正北面、东南面(北京-天津方向)、西南面(北京-保定方向)的O3体积分数较高. ⑤在0~3.5 km内,O3 与NO、NO2 和NO2/NO 值之间都存在着显著的相关关系, O3 与NO、NO2皆为负相关,但与NO2/NO 值为正相关. |
| 英文摘要 |
| Based on the aircraft sounding volume fraction concentration data of ozone (O3), nitrogen oxides (NO, NO2) and other data in Beijing from 2007 to 2010, temporal and spatial evolution of ozone concentration from the ground surface to 3.5 km altitude were studied. Results show that: ① Vertical profiles of monthly average O3 concentration were in good agreement, with increasing altitude, the concentrations were first increased and then decreased, and then remained almost constant, and there was a clear dividing line at 1.5 km altitude, the vertical gradient of the O3 concentration changed greatly below which, there were O3 high-value areas, which were influenced by human activities near the ground; the change of vertical gradient of O3 concentration was significantly reduced above 1.5 km altitude, this space was above the mixing layer, where the air mass movement was less affected by underlying surface, and the advection-diffusion played a crucial role in the local accumulation process of air pollutants. ② Changes of O3 concentration showed clear seasonal characteristics, O3 concentration was lower in spring and autumn, but higher in summer. In the months studied, no significant difference in monthly average O3 concentration from July to September was detected (P>0.05), but there was significant difference in other months (P<0.01). ③ In summer days (daytime), the variations in the vertical profiles of hourly O3 concentration were consistent with those of the monthly O3 concentration. The O3 concentration was lower near the surface within 1.5 km in the morning (09:00-10:00), and higher in the afternoon (15:00-16:00), with the maximum discrepancy of about 60×10-9 in the same altitude; there was minor difference in O3 concentration in altitude range of 1.5-3.5 km, generally fluctuating among 70×10-9-80×10-9. ④ For the regional distribution of O3 concentration, higher concentration within 0-2 km appeared near the Fourth Ring Road of city center and the surrounding areas, the main reasons for this distribution might be the presence of many strong sources of pollution emissions and low sink flow near the ground; within 2-4 km, in addition to the urban area of Beijing, higher O3 concentration areas were found in the north, the south-east (Beijing-Tianjin direction), the south-west (Beijing-Baoding direction). 5 There were significant correlation between O3 and NO, NO2 and NO2/NO within 0-3.5 km, O3 was negatively related with both NO and NO2, but positively correlated with the NO2/NO ratio. |
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