Characteristics of greenhouse gas concentrations derived from ground-based FTS spectra at Anmyeondo, South Korea

Abstract

Abstract. Since the late 1990s, the meteorological observatory established in Anmyeondo (36.5382° N, 126.3311° E, and 30 m above mean sea level) has been monitoring several greenhouse gases such as CO2, CH4, N2O, CFCs, and SF6 as a part of the Global Atmosphere Watch (GAW) Program. A high resolution ground-based (g-b) Fourier transform spectrometer (FTS) was installed at this observation site in 2013 and has been operated within the frame work of the Total Carbon Column Observing Network (TCCON) since August 2014. The solar spectra recorded by the g-b FTS cover the spectral range 3800 to 16 000 cm−1 at a resolution of 0.02 cm−1. In this work, the GGG2014 version of the TCCON standard retrieval algorithm was used to retrieve total column average CO2 and CH4 dry mole fractions (XCO2, XCH4) and from the FTS spectra. Spectral bands of CO2 (at 6220.0 and 6339.5 cm−1 center wavenumbers, CH4 at 6002 cm−1 wavenumber, and O2 near 7880 cm−1 ) were used to derive the XCO2 and XCH4. In this paper, we provide comparisons of XCO2 and XCH4 between the aircraft observations and g-b FTS over Anmyeondo station. A comparison of 13 coincident observations of XCO2 between g-b FTS and OCO-2 (Orbiting Carbon Observatory) satellite measurements are also presented for the measurement period between February 2014 and November 2017. OCO-2 observations are highly correlated with the g-b FTS measurements (r2 = 0.884) and exhibited a small positive bias (0.189 ppm). Both data set capture seasonal variations of the target species with maximum and minimum values in spring and late summer, respectively. In the future, it is planned to further utilize the FTS measurements for the evaluation of satellite observations such as Greenhouse Gases Observing Satellite (GOSAT, GOSAT-2). This is the first report of the g-b FTS observations of XCO2 species over the Anmyeondo station.

Towards Robust Calculation of Interannual CO2 Growth Signal from TCCON (Total Carbon Column Observing Network)

“…Theoretically, more stations could be used after 2011, but due to scanty long-term observations, we forfeited some stations from the analysis. This forfeiture has not affected global AGR TCCON because, if we include all three available MGRs from the excluded Anmyeondo site [94] to the calculation of global AGR TCCON , the difference between the final global AGR TCCON estimate and an experimental global AGR TCCON (with Anmyeondo) would be negligible (~0.1 ppm for 2016 and 2017).…”

Significance of Various Sensing Mechanisms for Detecting Local and Atmospheric Greenhouse Gases: A Review

“…intensity divided by the initial intensity, can be used to efficiently calculate gas concentration. [77]…”

“…Reproduced under the terms of CC BY license. [ 77 ] Copyright 2018, The Authors, published by Copernicus Publication. iv) Describe the actual equipment placement and semi‐automated monitoring of the observation laboratory.…”

Validation of GOSAT and OCO-2 against In Situ Aircraft Measurements and Comparison with CarbonTracker and GEOS-Chem over Qinhuangdao, China

“…The results from the validation of OCO-2 XCO 2 against ground-based FTS data from the nearest TCCON stations located in Japan found biases of 0.32 ppm, 2.31 ppm, and 0.30 ppm over Rikubetsu, Tsukuba, and Saga, respectively [29]. In addition, Oh et al [62] found that OCO-2 XCO 2 was overestimated by 0.18 ± 1.19 ppm compared to the Anmyeondo (South Korea) TCCON station data. A recent study [5] compared the OCO-2 XCO 2 with aircraft in situ data over Northeast China and found a bias of −4.68 ± 0.44 ppm in OCO-2 measurements.…”