临安区域本底站大气甲烷浓度变化特征

通过分析2006年8月～2009年7月临安区域大气本底站Flask瓶采样获得的CH4浓度特征，结合地面风向、后向轨迹、排放清单，研究了CH4浓度变化特征和长三角地区排放源对CH4浓度的影响作用。结果表明，临安区域大气本底站的CH4浓度分布在1 7584×10-9~1 9700×10-9，具有较明显的季节波动变化特征，浓度季节变化幅度为737×10-9；CH4浓度平均年增幅达176×10-9，增速较快。东北风和东南风时，CH4浓度较高；西南风时CH4浓度较低。导致CH4高浓度分布的气团主要来自临安站的东北、偏东方向；导致CH4低浓度分布的气团集中在西南 偏南

VARIATION CHARACTERISTICS OF ATMOSPHERIC CH4 CONCENTRATION AT LIN’AN REGIONAL BACKGROUND STATION

Characteristics of atmospheric CH4 concentration obtained by Flask measurements were analyzed at Lin’an regional background station from August 2006 to July 2009.According to the wind direction,backward trajectories and emission inventory,the variation characteristics of CH4 concentration was studied and the impact of emission sources on CH4 concentration was evaluated in Yangtze River Delta.The results revealed that atmospheric CH4 concentrations at Lin’an regional background station were between 1 758.4×10-9 and 1970.0×10-9.The CH4 concentration varied as seasons change and the annual difference was about 73.7×10-9.The long-term trend of CH4 concentration showed rapid growth year by year;the average growth rate was about 17.6×10-9/a.The CH4 concentrations were high when the winds were from the northeast and southeast,and the CH4 concentrations were low when the winds were from southwest.The air mass contained high CH4 concentrations mainly came from the northeast and east sector while the air mass contained low CH4 concentrations almost came from the southwest and south sector.