Short-term variations of atmospheric CO2 and dominant causes in summer and winter: Analysis of 14-year continuous observational data at Waliguan, China
Short-term variations of atmospheric CO2 and dominant causes in summer and winter: Analysis of 14-year continuous observational data at Waliguan, China
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夏季和冬季大气CO2的短期变化及主导因素——瓦里关14年连续观测资料分析
DOI：
10.1016/j.atmosenv.2013.04.067
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发表时间：
2013-10
影响因子：
5
通讯作者：
Lingxi Zhou
中科院分区：
文献类型：
--
作者：
Fang Zhang;Lingxi Zhou
利用1995-2008年中国西部洼里关山基线观测站连续14年的大气CO2混合比资料，分析了大气CO2的短期变化特征及其主要原因。包括修订后的数据和原始数据的比较和评价。夏季大气CO2浓度夜间升高，白天下降，日变化幅度为2.4 ± 0.3ppm（年际波动）。在冬季，白天的幅度通常为0.8 ± 0.2ppm。对局地水平风的分析表明，大气CO2日变化是附近源/汇变化和局地气象环流共同作用的结果。只有在冬季，我们发现一个0.03 ppm yr-1的统计增加趋势的CO2日峰-峰振幅，反映了当地的变化，在1995-2008年期间的源和汇的CO2在相对一致的气象条件。在夏季，当盛行风来自东北地区时，由于植被光合作用的增强，大气CO2减少;相反，在冬季，当陆地交换变弱，人为排放占主导地位时，大气CO2增加与来自北/东北或西北地区的空气包密切相关。冬季Δ CO2与ΔCO呈显著正相关（r> 0.9，p < 0.01），反映了一定天气气象条件下的共同来源。但它们在夏季没有表现出任何相关性。冬季Δ CO2和ΔCO线性拟合的截距接近于零，表明非CO相关CO2源或汇（如呼吸和光合作用）的影响较小，而夏季的截距则更为负值（7月低至-3.7 ppm），反映了生物圈CO2吸收的增强。冬季的ΔCO2/ΔCO比值为25-35 ppm ppm− 1，比北京的观测值高30%-42%，说明瓦里关地处偏远，受人类活动影响较小。
Using a 14-year revised dataset of atmospheric CO2mixing ratios continuously measured at Mount Waliguan Baseline Observatory of western China during 1995–2008, the short-term variations of ambient CO2and the dominant causes were studied. A comparison and evaluation of the revised and original data is included. Ambient CO2in summer was usually elevated during nighttime and declined in daytime with peak-to-peak diurnal amplitude of 2.4 ± 0.3 ppm (year-to-year fluctuations). In winter, there was often a small increase during daytime with amplitude of 0.8 ± 0.2 ppm. Analysis of the local horizontal winds shows that the diurnal cycles of ambient CO2are the combined result of changes of nearby sources/sinks and local meteorological circulation. Only in winter do we find a statistically increase trends of 0.03 ppm yr−1for CO2diurnal peak-to-peak amplitudes, reflecting local changes in sources and sinks of CO2during 1995–2008 under relatively consistent meteorological conditions. In summer, atmospheric CO2were depleted when prevailing winds came from the populated northeastern regions due to the enhanced vegetation photosynthesis which will result in low CO2; on the contrary to summer, elevated CO2were closely associated with air parcels from populated north/northeastern or northwestern regions in winter, when the terrestrial exchanges become weak and anthropogenic emissions dominate ambient CO2. ΔCO2and ΔCO showed significant positive correlation (r> 0.9,p< 0.01) in winter, reflecting common sources under certain synoptic meteorological conditions. But they didn't exhibit any correlation in summer. The intercepts for the linear fit of ΔCO2and ΔCO were close to zero in winter, indicating less influence from non-CO related CO2sources or sinks (e.g. respiration and photosynthesis), whereas the intercepts in summer were much more negative (as low as −3.7 ppm in July), reflecting enhanced biospheric CO2uptake. The ratio of ΔCO2/ΔCO was 25–35 ppm ppm−1in winter, which is approximately 30%–42% higher than that observed in Beijing and derived from emission inventories, reflecting less impact from human activities due to the remote location of Waliguan.
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影响因子：
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作者：
C. Zhao;C. Zhao;P. Tans
通讯作者：
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影响因子：
56.9
作者：
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影响因子：
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影响因子：
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作者：
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通讯作者：
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作者：
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