城市二氧化碳排放是全球大气二氧化碳的重要来源.利用涡度相关法测量的沈阳城市中心CO2浓度和通量资料,分析了2008年10~11月供暖期前后CO2浓度和通量的变化特征.研究表明,供暖期前后CO2浓度日变化呈双峰型曲线,第1个峰值出现在04:45,与日出时间一致,第2个次峰出现受机动车高峰和供暖影响;CO2通量研究表明,城市二氧化碳为净排放,供暖期前二氧化碳排放为52.69g·(m^2·d)^-1,供暖期后为82.50g·(m^2·d)^-1,植被光合作用起到了消减交通高峰时释放的CO2的作用,供暖期由于燃料燃烧在17:15~18:15出现明显CO2通量峰值,CO2排放比供暖期前增加29.37g·(m^2·d)^-1;CO2通量与温度的峰值和感热通量转为正值的时间有一定的对应关系.研究也指出,CO2浓度与通量的变化受风向与源区的协同影响.
Urban areas were significant contributors to global carbon dioxide emissions. The eddy covariance(EC)was used to measure carbon dioxide (CO2 ) concentration and flux data at urban area in Shenyang. This research analyzed the characteristics of atmospheric CO2 concentration and flux in October 2008 to November 2008 period before and in the heating period. The results showed that the daily variation of CO2 concentration was two-peak curve. The first peak time appeared as same as sunrise time,while the second peak time impacted by vehicles and heating. The result of CO2 flux showed that urban atmospheric CO2 was net emissions,vegetation photosynthesis absorbed CO2 of traffic,the CO2 flux peak appeared at 17:15-18:15 in the heating period,CO2 emission increased 29. 37 g·(m^2·d)^-1 in the heating period than that before the heating period; there was corresponding relationship between CO2 flux and the time when temperature peak and sensible heating flux ( Hc) turn positive. The results also indicated that atmospheric CO2 concentration and its flux were affected seriously by both wind direction and carbon sources.