Observation and modeling of vertical carbon dioxide distribution in a heavily polluted suburban environment

• Published in: Atmospheric and oceanic science letters = Daqi-he-haiyang-kexue-kuaibao Vol. 13; no. 4; pp. 371 - 379
• Main Authors: BAO, Zhongxiu, HAN, Pengfei, ZENG, Ning, LIU, Di, CAI, Qixiang, WANG, Yinghong, TANG, Guiqian, ZHENG, Ke, YAO, Bo
• Format: Journal Article
• Language: English
• Published: Beijing Taylor & Francis 03.07.2020; KeAi Publishing Communications Ltd; KeAi Communications Co., Ltd
• Subjects: Air masses; Balloons; Boundary layers; Calibration; Carbon dioxide; co2 vertical profile; Distribution; Emissions; Fossil fuels; Gas chromatography; Height; Instruments; Low cost sensor; meteorological conditions; Monitoring instruments; non-dispersive infrared (NDIR); Profiles; Remote sensing; Sensors; Suburban environments; tethered balloon; Transport; Troposphere; Vertical distribution; vertical profile; Vertical profiles; Weather forecasting; 低成本传感器；CO; 垂直廓线；系留气艇；气象条件；非分散红外
• ISSN: 1674-2834; 2376-6123
• DOI: 10.1080/16742834.2020.1746627

The vertical distribution of carbon dioxide (CO 2 ) is important for the calibration and validation of transport models and remote sensing measurements. Due to the large mass and volume of traditional instruments as well as supporting systems, in-situ measurements of the CO 2 vertical profile within the boundary layer are rare. This study used a miniaturized CO 2 monitoring instrument based on a low-cost non-dispersive infrared (NDIR) sensor to measure the CO 2 vertical profile and meteorological parameters of the lower troposphere (0-1000 m) in southwestern Shijiazhuang, Hebei Province, China. The sensors were onboard a tethered balloon with two processes: the ascending process and the descending process. The results showed that the overall trend of CO 2 concentration decreased with height. Weather conditions and CO 2 emission sources caused fluctuations in CO 2 concentrations. The CO 2 concentration varied from morning to afternoon due mainly to the faster spread of air mass during daytime, with strong convections and the accumulation of emissions at night. The low-cost sensor produced results consistent with the traditional gas chromatography method. The Weather Research and Forecasting model could not capture the CO 2 profiles well due mainly to the bad performances in boundary layer height and the potential outdated fossil fuel emissions around the experimental site. This experiment is the first successful attempt to observe the CO 2 vertical distribution in the lower troposphere by using low-cost NDIR sensors. The results help us to understand the vertical structure of CO 2 in the boundary layer, and provide data for calibrating and validating transport models.