Open AccessRetrieval of vertical profiles and tropospheric CO2 columns based on high-resolution FTIR over Hefei, China
Author(s) -
Changgong Shan,
Wei Wang,
Cheng Liu,
G. C. Yu,
Yu Xie,
Youwen Sun,
Qihou Hu,
Huifang Zhang,
Hao Yin,
Nicholas Jones
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.411383
Subject(s) - troposphere , trace gas , atmospheric sciences , environmental science , fourier transform infrared spectroscopy , analytical chemistry (journal) , chemistry , physics , optics , environmental chemistry
High-resolution solar absorption spectra, observed by ground-based Fourier Transform Infrared spectroscopy (FTIR), are used to retrieve vertical profiles and partial or total column concentrations of many trace gases. In this study, we present the tropospheric CO 2 columns retrieved by mid-infrared solar spectra over Hefei, China. To reduce the influence of stratospheric CO 2 cross-dependencies on tropospheric CO 2 , an a posteriori optimization method based on a simple matrix multiplication is used to correct the tropospheric CO 2 profiles and columns. The corrected tropospheric CO 2 time series show an obvious annual increase and seasonal variation. The tropospheric CO 2 annual increase rate is 2.71 ± 0.36 ppm yr -1 , with the annual peak value in January, and CO 2 decreases to a minimum in August. Further, the corrected tropospheric CO 2 from GEOS-Chem simulations are in good agreement with the coincident FTIR data, with a correlation coefficient between GEOS-chem model and FTS of 0.89. The annual increase rate of XCO 2 observed from near-infrared solar absorption spectra is in good agreement with the tropospheric CO 2 but the annual seasonal amplitude of XCO 2 is only about 1/3 of dry-air averaged mole fractions (DMF) of tropospheric CO 2 . This is mostly attributed to the seasonal variation of CO 2 being mainly dominated by sources near the surface.