大气14CO2观测：2010~2011年广州城市大气中化石源CO2浓度变化特征

摘要

中国科学院广州地球化学研究所(GIGCAS)大气CO2观测点的数据显示：2010年10月至2011年11月,该站点大气CO2浓度变化范围为460~550 mL/m3,月平均浓度介于470~530 mL/m3之间,呈现夏、秋季浓度低,春、冬季浓度较高的特点。大气CO2的δ13C值变化介于–9.00‰~–13.10‰之间,月平均值介于–9.60‰~–11.80‰之间,与大气 CO2浓度之间关系不显著,反映了人类活动对城市大气 CO2的影响。GIGCAS 站点大气CO2的Δ14C值波动剧烈,介于29.1‰~–85.2‰之间,月平均值波动范围为4.9‰~–41.7‰,年平均大气CO2的Δ14C值为–16.4‰。较高的Δ14C值出现在夏、秋两季(7~9月),均值约为–5.2‰,较低的Δ14C值出现在冬、春两季(12月至次年4月)、均值约为–27.1‰,据此计算得出的化石源CO2浓度变化范围为1~58 mL/m3,年平均值约24 mL/m3,较低的大气化石源CO2浓度出现在夏、秋两季(7~9月),均值为17 mL/m3,较高大气化石源CO2量出现在冬、春两季(12月至次年4月),均值约为29 mL/m3。气象条件和人类活动对城市大气化石源CO2浓度影响巨大,调整人类活动是减少大气化石源CO2污染的途径之一。%During October 2010 to November 2011, the urban atmospheric CO2 concentration observed in Guangzhou Institute of Geochemistry, Chinese Academy of Sciences in Guangzhou ranges from 550 mL/m3 to 460 mL/m3, with the monthly mean concentration fluctuating between 530 mL/m3 and 470 mL/m3. It shows lower concentrations in summer and autumn, and higher concentrations in spring and winter. The CO2δ13C values vary between –9.00‰ and –13.10‰, with the monthly mean values fluctuating between –9.60‰ and –11.80‰. The relationship between CO2 concentration and δ13C values is not significant, reflecting the influence from human activities on the urban atmospheric CO2. The Δ14C values of urban atmospheric CO2 in Guangzhou fluctuate dramatically from 29.1‰to–85.2‰, with an annual mean value of about–16.4‰. The monthly meanΔ14C values vary between 4.9‰ and –41.7‰. The higher Δ14C values mainly appear in summer and autumn (July to September), and the mean value is about–5.2‰, while, the lowerΔ14C values mainly appear in spring (December to April next year) and winter, with an average value of about –27.1‰. According to the Δ14C values, fossil fuel-derived CO2 concentrations are calculated ranges from 1 mL/m3 to 58 mL/m3, with the annual mean concentration of about 24 mL/m3. Correspondingly, the lower fossil fuel-derived CO2 concentrations appear in summer and autumn (July to September) and the mean value is about 17 mL/m3, while, the higher fossil fuel-derived CO2 concentrations appear in spring and winter (December to April next year) and the average value is about 29 mL/m3. Weather conditions and human activities play an important role on the fuel-derived CO2 contributed to urban atmospheric CO2. It is feasible that human can reduce the degree of fuel-derived CO2 pollution in urban atmosphere in Guangzhou through adjusting human activities.