长沙市郊大气CH_4浓度变化特征  

Distribution of CH_4 in the Suburb of Changsha City,China

作　　者：刘鲁宁[1] 王迎红[1] 徐小娟[1] 王卫东[2] 王跃思[1] 

机构地区：[1]中国科学院大气物理研究所大气边界层物理与大气化学国家重点实验室,北京100029 [2]中国科学院亚热带农业生态研究所,长沙410125

出　　处：《环境科学》2013年第11期4165-4170,共6页Environmental Science

基　　金：中国科学院战略性先导科技专项(XDA05100100);国家自然科学基金创新研究群体项目(41021004);国家自然科学基金重点项目(41230642)

摘　　要：为研究长江中游地区大气CH4浓度（体积分数）变化特征，2007-2011年，利用内表面硅烷化的苏玛罐采样、GC／FID方法对长沙市郊空气样品中CH4浓度进行测定分析，并结合地面气象要素和后向轨迹，探讨CH4浓度变化特征与源汇的关系．结果表明，观测期间，大气CH4年平均浓度变化范围在2012×10-9～2075×10-9之间，季节变化特征为秋季高，春季低，浓度年较差为152×10-9．通过分析地面风和气团传输对长沙市郊大气CH4的影响表明，长沙市郊大气CH4浓度受西北风和偏南风交替控制，贡献率分别为41．1％和20．4％；引起CH4抬升的地面风包括：4个季节中的w-WNW-NW、夏季ESE-SE和冬季s，春夏季节S则导致CH4浓度降低；夏秋季节源自水稻产区的气团、冬春季节源自能源消费量较高地区的气团，对长沙市郊CH4浓度的抬升有显著贡献，南方长距离传输气团有利于CH4扩散和清除．To study the variation of atmospheric CH4 concentration in the Yangtze River region, air samples which collected weekly using flasks from the suburb of Changsha City from 2007 to 2011 and the CH4 concentration was measured by gas chromatography. CH4 concentrations were analyzed combined with ground meteorological elements and backward trajectories to explore the CH4 concentration variations with source-sink relationships. The results showed that during the observation period, the annual mean concentration of CH4 was in the range 2 012× 10-9-2 075 × 10-9（ volume mixing ratio, the same below）. The difference between the maximum and minimum monthly mean of CH4 concentrations was 152× 10-9, with the highest concentration observed in autumn and the lowest in spring. Analysis of the surface wind showed that the concentration of CH4 was controlled by northwest wind and southerly winds alternately, and the contribution rate was 41.1% and 20.4% , respectively. Surface winds causing CH4 concentration uplift included W-WNW-NW in all four seasons, ESE-SE in summer and S in winter; while S in spring and summer have resulted in the decrease of CH4 concentration. Analysis of the air mass transport showed that the concentration of CH4 in the suburb of Changsha was significantly contributed by air masses from rice-producing areas in summer and high energy consumption areas in winter, and was cleared by air masses of long-distance transport from southern district.

关 键 词：大气CH4 长沙 季节变化 地面风 后向轨迹 

分 类 号：X511[环境科学与工程—环境工程]