Characterization of urban CO2 column abundance with a portable low resolution spectrometer (PLRS): Comparisons with GOSAT and GEOS-Chem model data

Yuan Tian; Youwen Sun; Cheng Liu; Pinhua Xie; Kalok Chan; Jin Xu; Wei Wang; Jianguo Liu

doi:10.1016/j.scitotenv.2016.12.005

Characterization of urban CO₂ column abundance with a portable low resolution spectrometer (PLRS): Comparisons with GOSAT and GEOS-Chem model data

Sci Total Environ. 2018 Jan 15:612:1593-1609. doi: 10.1016/j.scitotenv.2016.12.005. Epub 2017 Mar 28.

Authors

Yuan Tian¹, Youwen Sun², Cheng Liu³, Pinhua Xie⁴, Kalok Chan⁵, Jin Xu⁴, Wei Wang⁴, Jianguo Liu⁴

Affiliations

¹ Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
² Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China; Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
³ School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China; Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China. Electronic address: chliu81@ustc.edu.cn.
⁴ Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China.
⁵ Meteorological Institute, Ludwig-Maximilians Universität München, Munich, Germany.

PMID: 28359568
DOI: 10.1016/j.scitotenv.2016.12.005

Abstract

We presented the characterization of urban CO₂ column abundance (XCO₂) in Hefei, China using a portable low resolution spectrometer (PLRS). An optimized correction spectrum was introduced in the spectral fitting to improve CO₂ retrieval. A pronounced seasonal cycle and diurnal variation were observed with a precision of ~0.12%. The CO₂ concentrations in winter are about 5-10ppm higher than those in summer. Most diurnal variations exhibited downward trends. The measurement in the early morning is about 2-5ppm higher than the late afternoon observation. The causes of the seasonal and diurnal trends were systematic analyzed. The coincident CO₂ time series were compared with the Greenhouse Gases Observing SATellite (GOSAT) data and the GEOS-Chem global 3-D tropospheric chemistry model data. We found the ground based (g-b) PLRS data are systematically higher than the GOSAT and the GEOS-Chem data. Compared to the GOSAT data, the g-b PLRS data are 0.26ppm (0.07%) higher with a standard deviation of 1.70ppm (0.43%). Compared to the smoothed GEOS-Chem model data, the g-b PLRS data shows a 1.31ppm (0.33%) higher with a standard deviation of 5.30ppm (0.87%). The g-b PLRS generally reproduced the seasonal cycle observed by GOSAT and GEOS-Chem model with correlation coefficients (r) of 0.82 and 0.64, respectively.

Keywords: Carbon dioxide; City emission; GEOS-Chem; GOSAT; Remote sensing; Seasonal cycle.