Analysis on source features of halogenated gases at Shangdianzi regional atmospheric background station
Analysis on source features of halogenated gases at Shangdianzi regional atmospheric background station
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DOI：
10.1016/j.atmosenv.2012.04.042
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发表时间：
2012-09
影响因子：
5
通讯作者：
X. An;Ling-xi Zhou;B. Yao;Lin Xu;Lin Ma
中科院分区：
文献类型：
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作者：
X. An;Ling-xi Zhou;B. Yao;Lin Xu;Lin Ma
利用拉格朗日粒子积分轨迹模型HYSPLIT，对2008-2010年上店子站5天的大气环流轨迹进行季节分类，每天4次计算，并采用轨迹聚类分析方法。根据现场卤代气体（包括CFC-11、CFC-12、CCL 4、CHCL 3、CH 3Br、SF6、H-1301和HCFC-22）的浓度测量结果，研究了上店子试验区不同季节不同轨迹对卤代气体浓度的影响。同时，利用同一测站的风速资料和同期的实测浓度资料，分别计算了CFC-11、CFC-12、CCL 4、CHCL 3、CH 3Br、SF6、H-1301和HCFC-22的负荷量。后向轨迹聚类分析结果表明，在SDZ局地气团中占较大比例的东南、西南方向气团在底边界层内移动缓慢，有利于污染物在边界层内的积累，导致各团中卤代烃平均浓度最高。相反，在高海拔快速移动的西北气团对应的卤烃的平均浓度被发现有一致的低值。浓度负荷分析表明，所有卤代物种的最大浓度负荷方向为WSW和SW，最小浓度负荷方向为NNW、NNE、NE和ENE。我们还发现，在SW-S-SE扇区是高浓度负荷部分，而在NW-N-NE扇区是低浓度部分。轨迹聚类分析和浓度负荷结果表明，上述卤代物向SDZ的SE-S-SW方向为高污染源方向，反映了区域尺度上人类活动对SDZ大气污染物输送的影响，而NW-N-NE方向为该站的清洁方向。
In the study, the five-day back-trajectories collected by Shangdianzi Station were categorized by season, calculated four times a day during the period of 2008–2010, based on the Lagrangian particle integrated trajectory model HYSPLIT, and using the back-trajectory cluster analysis method. Efforts were made to understand the impacts of different trajectories on the concentration of halogenated gases over the site of Shangdianzi (SDZ) in different seasons, in line with the in-site concentration measurements of halogenated gases, including the 8 species of CFC-11, CFC-12, CCL4, CHCL3, CH3Br, SF6, H-1301, and HCFC-22. Meanwhile, the wind data collected by the same station and the concentration observed during the same period were employed to calculate the loadings of CFC-11, CFC-12, CCL4, CHCL3, CH3Br, SF6, H-1301, and HCFC-22, respectively. The result of back-trajectory cluster analysis suggests that air masses from southeast and southwest accounting for a large proportion of local air masses at SDZ always move slowly within the bottom boundary layer, which is beneficial for the accumulation of pollutants within the boundary layer and leads to the highest mean concentrations of halocarbons among all the clusters. Conversely, the mean concentration of halocarbons corresponding to the fast-moving northwest air masses at high altitude is found to have unanimously low values. The analysis of the concentration loadings proves that WSW and SW are the directions for the maximum concentration loading of all halogenated species, whereas NNW, NNE, NE and ENE are the directions for the minimum concentration loading. We also find that the sector in SW–S–SE is the high concentration loading part, while the sector in NW–N–NE is the low concentration part. The trajectory cluster analysis and concentration loading results indicate that the SE–S–SW towards SDZ is the high pollution source direction for the halogenated species mentioned above, which reflects the influence of human activities on the air pollutant transportation at SDZ in a regional scale, while NW–N–NE represents the clean direction of the station.