2019年瓦里关地区CO2和CH4浓度变化特征及潜在来源分析
Variation Characteristics of CO2 and CH4 Concentrations in Waliguan Area in 2019 and Potential Source Analysis
中文摘要：
利用2019年瓦里关站在线温室气体观测数据，分析了该站CO2、CH4浓度的季节和日变化特征，探讨了CO2和CH4可能的潜在源区。结果表明，2019年瓦里关地区CO2和CH4浓度分别为412.07±4.78 ppm（1 ppm＝10-6）和1935.17±21.13 ppb（1 ppb＝10-9），略高于全球平均浓度水平。大气CO2浓度季节变化呈现夏秋季低、冬春季较高的特征，CH4浓度变化特征正好与CO2的相反，呈现为夏秋季高，冬春季低，这可能与瓦里关地区夏秋季放牧活动增加和来自兰州—西宁城市群主导气流的输送有关。CO2和CH4浓度平均日变化规律明显，其变化特征是源、汇强度变化和大气扩散强度变化相互作用的结果。后向轨迹聚类表明，来自甘肃中部和青海东北部兰州—西宁城市群的气团对瓦里关CO2和CH4浓度贡献最大。PSCF法分析同样表明，兰州—西宁城市群是瓦里关CO2和CH4最主要的潜在源区。
中文关键词：
瓦里关，二氧化碳，甲烷，后向轨迹，PSCF，潜在源区，变化趋势
KeyWords：
Waliguan, CO2, CH4, backward trajectory, PSCF, potential source area, change trend
Abstract：
Based on the on-line greenhouse gas observation data of Waliguan Station in 2019, the seasonal and daily variation characteristics of CO2 and CH4 at the station are analyzed, and the possible potential source areas of CO2 and CH4 are discussed. The results show that the concentrations of CO2 and CH4 in Waliguan area in 2019 are 412.07±4.78 ppm and 1935.17±21.13 ppb respectively, both of which are slightly higher than the global mean values. The seasonal variation of atmospheric CO2 is low in summer and autumn, and high in winter and spring. The variation of CH4 concentration is just the opposite to that of CO2. It is high in summer and autumn, and low in winter and spring. The seasonal variations may be related to the increased summerautumn grazing activities in Waliguan and the transport of the dominating air flow from Lanzhou-Xining urban group. The average daily variation of CO2 and CH4 concentrations is evident, characterized by the interaction between changes in source-sink intensity and atmospheric diffusion intensity. The backward trajectory clustering shows that the air mass from Lanzhou-Xining urban group in Central Gansu and northeast Qinghai contributes the most to the CO2 and CH4 in Waliguan. PSCF analysis also shows that Lanzhou-Xining urban group is the main potential source of CO2 and CH4 in Waliguan.