摘要
本文报道了从2009年8月至2010年7月在青岛市崂山区(36.03°N,120.18°E)以每周3天的采样频率连续采集近地面大气气溶胶12个月,测定近地面空气中~7Be浓度值的研究结果。青岛市近地面空气中~7Be浓度的变化范围为1.52～14.58mBq/m^3,年平均值为6.83±0.40mBq/m^3,显著高于全球平均水平。最高值出现在4月,最低值出现在7月。秋季为~7Be浓度平均值最高的月份(9.02mBq/m^3);其次为春季(7.39mBq/m^3);夏季为最低的月份(4.46mBq/m^3)。~7Be浓度秋季水平高于夏季水平一倍。"春季泄漏"现象出现在4月份。青岛地区夏季受东南季风的影响,近地面空气中~7Be浓度偏低。2009年秋季受厄尔尼诺影响,大气环流异常以及台风频发促使平流层底部和对流层大气的交换,导致近地面空气中~7Be的增多。冬季近地面空气中7Be浓度略高于夏季。青岛市近地面空气中~7Be浓度的振荡变化与青岛年内气象条件振荡有关,季节性变化明显,反映了东亚季风区大气环流的特点。
Near-surface atmospheric aerosol samples were collected at sampling frequency oi 3 a per week for one year from August 2009 to July 2010 in Laoshan District, Qingdao （36.03 °N, 120. 18°E）. The samples were analyzed for cosmogenic nuclide ^7Be. The resuh showed that the annual average ^7Be concentration was 6. 83 ±0. 40mBq/m^3 , with the variation range from 1.52mBq/m^3 to 14. 58mBq/m^3 ,significantly higher than global average level. The maximum was observed in April, while the minimum was observed in July. Autumn was the season in which the monthly average ^7Be concentrations were highest（9. 02mBq/m^3） ,followed by spring（7.39mBq/m^3） ,while summer was the lowest ^7Be season（4. 46mBq/m^3） which was one-fold lower than that in autumn. The highest peak of ^7Be concentration in April may have association with the ＂spring discharge＂ episode. South-eastly is dominant in summer which may cause lower ^7Be oberseved in summer. In autumn due to abmormal atmospheric circulation and E1 Nifio as well as frequent typhoons ,which may enhance the air exchange between the lower stratosphere and troposphere, the near surface ^7Be concentrations increased higher than the annual mean. The ^7Be level in winter was slightly higher than that in summer. The seasonal variations of ^7Be concentrations the near-surface air in Qingdao were associated with the oscillation of weather conditions ,reflecting the feature of the East Asian Monsoon climate system.
出处
《第四纪研究》
CAS
CSCD
北大核心
2012年第3期423-429,共7页
Quaternary Sciences
基金
国家自然科学基金项目(批准号:41073011
41003044和40773010)资助
