Spatial and temporal variations of CO2 mole fractions observed at Beijing, Xianghe, and Xinglong in North China
Spatial and temporal variations of CO2 mole fractions observed at Beijing, Xianghe, and Xinglong in North China
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DOI：
10.5194/acp-21-11741-2021
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发表时间：
2021-08
影响因子：
6.3
通讯作者：
Yang Yang-Yang;Minqiang Zhou;Ting Wang;B. Yao;P. Han;Denghui Ji;Weiguang Zhou;Yele Sun;Geng-chen Wang;Pucai C. Wang
中科院分区：
文献类型：
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作者：
Yang Yang-Yang;Minqiang Zhou;Ting Wang;B. Yao;P. Han;Denghui Ji;Weiguang Zhou;Yele Sun;Geng-chen Wang;Pucai C. Wang
摘要。利用Picarro G2301空腔振荡光谱仪对北京（BJ）、香河（XH）和兴隆市（XL）的大气CO2摩尔分数进行了观测。本文首次对该测量系统进行了较为全面的描述。这三个站点之间的地理距离都在200公里以内，但它们的周边环境却截然不同：北京位于特大城市内；XH在郊区；XL在乡下的一座山上。2018年10月至2019年9月，BJ、XH和XL的CO2摩尔分数均值和标准差分别为448.4±12.8、436.0±9.2和420.6±8.2 ppm。3个站点CO2的季节变化相似，冬季最大，夏季最小，以陆地生态系统为主。然而，与XL相比，BJ和XH的CO2季节变化受人类活动的影响更大。以XL点的CO2为背景，在BJ点和XH点同时观测到CO2增强。CO2的日变化受边界层高度、光合作用和人类活动的驱动。我们还将BJ、XH和XL与美国5个城市站点的CO2测量值进行了比较，发现BJ的CO2平均浓度最大。此外，我们还讨论了风对BJ和XL的CO2摩尔分数的影响。该研究揭示了华北地区CO2摩尔组分的时空变化特征。
Abstract. Atmospheric CO2 mole fractions are observed at Beijing (BJ), Xianghe (XH), and Xinglong (XL) in North China using Picarro G2301 cavity ring-down spectroscopy instruments. The measurement system is described comprehensively for the first time. The geographical distances among these three sites are within 200 km, but they have very different surrounding environments: BJ is inside the megacity; XH is in the suburban area; XL is in the countryside on a mountain. The mean and standard deviation of CO2 mole fractions at BJ, XH, and XL between October 2018 and September 2019 are 448.4±12.8, 436.0±9.2, and 420.6±8.2 ppm, respectively. The seasonal variations of CO2 at these three sites are similar, with a maximum in winter and a minimum in summer, which is dominated by the terrestrial ecosystem. However, the seasonal variations of CO2 at BJ and XH are more affected by human activities as compared to XL. Using CO2 at XL as the background, CO2 enhancements are observed simultaneously at BJ and XH. The diurnal variations of CO2 are driven by the boundary layer height, photosynthesis, and human activities at BJ, XH, and XL. We also compare the CO2 measurements at BJ, XH, and XL with five urban sites in the USA, and it is found that the CO2 mean concentration at BJ is the largest. Moreover, we address the impact of the wind on the CO2 mole fractions at BJ and XL. This study provides an insight into the spatial and temporal variations of CO2 mole fractions in North China.