Study On The Temporal And Spatial Variation Characteristics Of CO₂ And HFC_S Concentrations In Beijing-Tianjin-Hebei

The diurnal,seasonal and long-term trends of CO₂ in Beijing-Tianjin-Hebei region were analyzed by the combination of near-ground observation and aircraft flight detection,and the influence of long-distance transport on atmospheric CO₂ concentration in the two stations was analyzed by the HYSPLIT backward trajectory model.The interannual variation characteristics,concentration levels and emissions of HFC_S were analyzed based on the online observation data of HFC_Sfrom Beijing Shangdianzi Station in 2018.The main conclusions are as follows:（1）Based on the analysis of online observation data:The daily amplitude of Shangdianzi Station was the highest in summer and the lowest in winter.With the change of sunrise time,the occurrence time of the maximum value in spring,summer and autumn was delayed by 1hour.The daily amplitude of Luancheng Station was basically in the same step,with a small high value at 14:00 in summer,which was affected by the nearby source area,so that its concentration had a brief spike.The highest values of CO₂ concentration occurred around sunrise,the lower layer was earlier than the upper layer,and Shangdianzi was earlier than Luancheng.In Shangdianzi Station,the maximum and minimum values of CO₂ concentration appeared in summer,while in Luancheng,the maximum values appeared in winter and the minimum values appeared in spring.This indicates that Shangdianzi station is located in the"clean"atmosphere area,while in Luancheng,it is located in the urban area,which is affected by the urban emission,especially in winter,the increase of residents’activities and the emission of heating coal leads to a higher CO₂ concentration.The average seasonal variation of atmospheric CO₂ concentration in the lower and upper layers of Shangdianzi and Luancheng was lower in summer and higher in winter and early spring,which was similar to the seasonal variation of Marine boundary layer（MLO）,reflecting the periodic seasonal variation of terrestrial ecosystem.However,Luancheng station showed a high value in winter and a slightly higher value in late spring and early summer,which was not consistent with the fluctuation law of background atmospheric CO₂ concentration in the northern hemisphere due to the influence of environmental factors in the surrounding areas.（2）The trace cluster analysis showed that the CO₂ concentration of Shangdianzi was mainly affected by the air masses from remote areas such as Inner Mongolia,Mongolia and Siberia of China.The trace air masses were the dominant air flow in spring,autumn and winter,accounting for about 50%of the total amount of the trace,and their influence on CO₂ was manifested as lifting effect.The second category is from the Beijing-Tianjin-Hebei region,which is the dominant air flow in summer and is a polluted sector.Luancheng is also affected by these two kinds of air masses,but it is also affected by Shanxi coal mining,so that China Mongolia,Mongolia,Siberia to the air masses no longer clean.Two games points calculated WCWT potential source area and PSCF basic consistent,Turkey stone on the bottom and pollution concentration polluting source area is different,basic are from pollution concentration and around beijing-tianjin-hebei,the impact of urban air pollution and the background concentration is mainly influenced by China’s Inner Mongolia,Mongolia,Siberia,the influence of the air mass in remote areas.The high pollution source areas of Luancheng background and pollution concentration are basically from the influence of air mass pollution in Beijing-Tianjin-Hebei and its surrounding cities.（3）By the king-air 350 high-precision CO₂ analyzer and related auxiliary equipment,to shijiazhuang,xingtai CO₂ concentration above the plane detection,detection during total of flying 4,7 groups of CO₂concentration in the vertical profile data,the detection of CO₂concentration during the minimum value is 398.3 ppm,a maximum of 414.6ppm,more vehicles vertically average concentration for（402.3±1）ppm.The CO₂ concentration increased first and then decreased with the increase of altitude,and there was a clear dividing line at about 1000-2000m.The CO₂concentration at the same altitude layer changed significantly under 1000m due to the influence of near-surface emission sources.The CO₂ at Xingtai station was significantly correlated with the concentration of CH₄,with the correlation coefficient r≥0.90.The high correlation coefficient indicated that CO₂ and CH4 at Xingtai station had the same source.（4）A gas chromatograph/mass spectrometer（GC/MS）system was used for in-site measurements of atmospheric hydrofluorocarbons（HFC_S）at the Shangdianzi Regional Background Station.The background mixing ratios of HFC-23,HFC-32,HFC-125,HFC-134a,HFC-143a,HFC-152a,HFC-227ea,HFC-236fa,HFC-245fa,HFC-365mfc,and HFC-4310mee.The background mixing ratio of HFC-32、HFC-125、HFC-134a、HFC-143a、HFC-227ea exhibited a linear increasing trend.while HFC-152a background data showed a strong seasonal variation.A tracer-radio method was applied to estimate the emissions of HFC-23,HFC-32,HFC-125,HFC-134a,HFC-152a,HFC-236fa,HFC-245fa emissions using CO as a tracer.and the emissions of HFC-32,HFC-125 and HFC-134a were increased by about 3-4 times compared with the period of 2010-2011.