云南香格里拉本底站大气CH_4体积分数及变化特征  

Variation of CH_4 concentrations at Yunnan Xianggelila background station in China

作　　者：方双喜[1] 李邹 周凌晞[1] 许林[1] 

机构地区：[1]中国气象科学研究院大气成分研究所,中国气象局大气化学重点开放实验室,北京100081 [2]云南迪庆州气象局,迪庆674400

出　　处：《环境科学学报》2012年第10期2568-2574,共7页Acta Scientiae Circumstantiae

基　　金：国家重点基础研究发展计划(973)项目(No.2010CB950601);国家自然科学基金项目(No.41175116);科技部国际合作项目(No.2011DFA21090)~~

摘　　要：利用基于光腔衰荡光谱(CRDS)技术自组装的大气CH4在线观测系统,于2010年7月—2011年10月在云南香格里拉大气本底站对大气CH4进行了在线观测.结果发现,该站春、夏、秋、冬季CH4平均本底值分别为(1850.7±6.9)×10-9(体积分数,下同)、(1850.9±13.4)×10-9、(1865.6±16.1)×10-9和(1839.2±6.5)×10-9.全年体积分数在9月最高,12月最低,月均值振幅约39.6×10-9.4季日平均最低值均出现在14:00—16:00.日变化振幅在冬季最小,秋季最大,分别为4.4×10-9和10.0×10-9.西南来向的地面风会明显抬升CH4体积分数,而北偏东来向的地面风显著降低观测结果.通过4季每日整点后向轨迹聚类计算,结合观测资料分析发现,该站CH4主要受西南来向气团传输影响,尤其在春、夏、秋3季.Atmospheric CH4 concentration was continuously measured at Xianggelila background station by Cavity Ring Down Spectroscopy system from July 2010 to October 2011.The average CH4 background concentrations during spring,summer,autumn and winter were（1850.7±6.9）×10^-9,（1850.9±13.4）×10^-9,（1865.6±16.1）×10^-9 and（1839.2±6.5）×10^-9,respectively.The monthly average variation reached a maximum in September and a minimum in December with the amplitude about 39.6×10^-9.The hourly average CH4 concentration exhibited evident diurnal variation with minimal values around 14：00—16：00 for all seasons.The daily variation amplitude was the lowest in the winter（4.4×10^-9） and the highest in the autumn（10.0×10^-9）.Evident elevation of CH4 concentration was observed when the surface wind was from the southwest,whereas great decrease was associated with north to northeasterly wind.Combined with the observed CH4 concentrations,cluster analysis of 3 day backward trajectories suggested that the observed CH4 concentration during the four seasons at the station was mainly affected by the southwest air mass transport,especially in spring,summer and autumn.

关 键 词：本底站 CH4 体积分数 地面风 后向轨迹 

分 类 号：X511[环境科学与工程—环境工程]