北京上甸子站大气CH_4数据筛分及变化特征  

Data selection and variation characteristics of atmospheric CH_4 observed at Shangdianzi station in Beijing

作　　者：夏玲君[1] 刘立新[2] 

机构地区：[1]江西省气候中心,江西南昌330096 [2]中国气象局气象探测中心,北京100081

出　　处：《中国环境科学》2017年第11期4044-4051,共8页China Environmental Science

基　　金：国家国际科技合作专项(2015DFG21960);国家自然科学基金项目(40905066;41175116;41273097);上海市气象与健康重点实验室开放基金项目(QXJK201501);江西省气象科技面上项目(2017)

摘　　要：基于气团72h后向轨迹输送特征,结合数值统计方法,对北京上甸子站2010~2014年瓶采样样品大气CH_4进行污染/非污染数据筛分.结果表明约42%的数据筛分为污染数据,剩余数据则被认为是未受局地源汇污染、混合较为均匀的本底数据.基于这些本底数据对上甸子站大气CH_4本底浓度变化特征进行研究,结果表明:观测期间上甸子站大气CH_4本底浓度从1884.0×10^(-9)(2010年)增长到1916.4×10^(-9)(2014年),年均增长率为8.5×10^(-9)/a.其季节变化特征与北半球平均状况类似,冬春季高、夏秋季低,高值出现在1~2月,低值出现在6~7月,季节振幅达32.8×10^(-9),主要与·OH自由基浓度季节变化有关.此外,CH_4本底浓度年均值及平均季节变化月均值均高于同纬度带海洋边界层水平及全球大气本底站瓦里关站.Based on transport characteristics of air mass 72 h back trajectories and statistical data filtered method, measurement data of atmospheric CH_4 obtained at Shangdianzi(SDZ) regional background station in Beijing during 2010 and 2014 were analyzed for non-pollution and pollution events. About 42% of the complete data set was filtered as pollution data, and the remainders not polluted by local emission sources were flagged as 'representative background data'. Variations of background CH_4 concentrations at SDZ station can be obtained based on the 'representative background data'. The annual mean background CH_4 concentrations varied from 1884.0×10^(-9) in 2010 to 1916.4×10^(-9) in 2014 observed at SDZ, with the averaged growth rate of 8.5 ×10^(-9)/a. Background atmospheric CH_4 presented obvious seasonal fluctuations, the higher and lower levels of seasonal CH_4 cycle appeared in Jan-Feb and Jun-Jul, respectively, with the peak-to-peak amplitude of 32.8×10^(-9). The seasonal variations of atmospheric CH_4 might be owing to the variations of OH concentration in atmosphere. Furthermore, the annual and 'detrended' monthly CH_4 background concentrations observed at SDZ were higher than those of MBL at the same latitude and WLG global baseline station.

关 键 词：大气CH4 后向轨迹 数据筛分 北京上甸子站 本底水平 

分 类 号：X511[环境科学与工程—环境工程]