城市节假日前后碳通量特征及其与车流量关系

全球变化背景下,城市作为主要的碳源,对其碳循环的研究成为陆地生态系统碳循环的重点内容之一。以上海市奉贤区为研究对象,基于涡度相关技术,结合定点连续观测的车流量数据,分析节假日（元旦）前后CO2浓度和碳通量的变化特征,及其与车流量的关系。结果表明,CO2浓度和通量日变化呈现明显的双峰型曲线,节假日CO2浓度（385.6mg/L）平均值低于工作日（401.1 mg/L）。在本研究时段内该系统表现为碳源,尽管在白天的某些时段是碳汇,表明城市系统碳通量受自然和人为2个因素共同作用,自然因素比如该系统中的香樟、雪松等常绿植物的光合作用,人为因素由人类活动造成。基于车流量与交通流量的线性回归分析表明,机动车量碳排放对于碳通量变化产生18%的贡献。

Characteristics of CO_2 flux before and after holidays and its relationship with traffic volume in urban area

Under the global climate change background,urban areas are the mjor carbon sources,the research of urban ecosystem carbon cycle plays a very important role in terrestrial ecosystem carbon cycle study field.The eddy covariance technology was used to measure carbon dioxide concentration and flux data,combined with continuous traffic volume data in Fengxian District of Shanghai.This research analyzed the characteristics of carbon dioxide concentration and flux data and their relationships with traffic volume.The results showed that the daily variation of CO 2 concentration was two-peak curve,the CO 2 concentration in work days（401.1 mg / L） was lager than in holidays（385.6 mg / L）.This ecosystem was a carbon source,though it was a carbon sink in the daytime,which showed that urban ecosystem carbon flux is influenced by natural and human activities factors,eg.,photosynthesis of evergreen trees（camphor tree,cerdar） play a part in carbon sink in daytime,while human activities play a part in carbon sources.Carbon emissions from traffic contributed 18% to the CO 2 flux variation based on linear regression analysis.