Seasonal variations in SO2 plume transport over Japan:: Observations at the summit of Mt. Fuji from winter to summer
Seasonal variations in SO2 plume transport over Japan:: Observations at the summit of Mt. Fuji from winter to summer
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DOI：
10.1016/j.atmosenv.2006.06.017
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发表时间：
2006-11-01
影响因子：
5
通讯作者：
Dokiya, Yukiko
中科院分区：
文献类型：
--
作者：
Igarashi, Yasuhito;Sawa, Yosuke;Dokiya, Yukiko
我们在山顶连续测量二氧化硫浓度。2004年1月至7月，日本富士（海拔3776米）。这些数据包括第一个数据集，填补了以前的差距SO2时间序列的春季对流层中部日本。时间序列显示了从冬季到春季高SO2远程传输事件的趋势。SO2浓度的升高总是伴随着CO和Rn-222浓度的升高，这种事件的后向轨迹表明了大陆起源。这些数据清楚地显示了亚洲气流经日本流向北太平洋的零星迹象。这种高SO2事件的强度和频率在春季下降。观测到的SO2事件的季节性变化实际上可能与亚洲大陆SO2排放的季节性无关，因为SO2事件的季节性模式显示出与现场观测到的盛行风向和相对湿度（RH）相似的相移。大气质量的变化表明，每天的后向轨迹分析也可以解释所观察到的时间变化的SO2事件。一个主要因素似乎是二氧化硫在远距离迁移过程中从大陆污染羽流中的去除。在深冬，含SO2的污染空气是干燥的;因此，在每年的这个时候，很少有SO2被云过程带走。在春季，空气质量的性质发生变化，湿度水平的增加导致云过程对SO2的去除增加。相对湿度数据沿着空气质量的旅行路径也支持云的过程在减少污染羽流内的二氧化硫浓度的重要性。(c)2006爱思唯尔有限公司保留所有权利。
We undertook continuous measurements of SO2 Concentrations at the summit of Mt. Fuji, Japan (3776 m above sea level), during the period January to July, 2004. These data include the first data set that fills the previous gap in SO2 time series for the springtime middle troposphere over Japan. The time series shows trends in high-SO2 long-range transport events from winter to spring. Elevated SO2 concentrations are always accompanied by elevated CO and Rn-222 concentrations, and backward trajectories for such events indicate a continental origin. These data display clear sporadic signatures of Asian outflow over Japan to the North Pacific. Such high-SO2 events decline in strength and frequency during spring. The observed seasonal variation of SO2 events may in fact have nothing to do with seasonality in SO2 emissions from the Asian continent, as seasonal patterns in SO2 events show a similar phase shift to that of the prevailing wind direction and relative humidity (RH) observed on-site. The changes in air mass indicated by daily backward trajectory analysis may also explain the observed temporal changes in SO2 events. A major factor appears to be the removal of SO2 from the continental pollution plume during long-range transport. The SO2-bearing polluted air is dry during the depths of winter; accordingly, little SO2 is removed by cloud processes at this time of year. The nature of the air mass changes during spring when increasing humidity levels lead to the increased removal of SO2 by cloud processes. RH data along the air mass travel path also support the importance of cloud processes in reducing SO2 concentrations within the pollution plume. (c) 2006 Elsevier Ltd. All rights reserved.