the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Variations and correlations of CO, C2H2, C2H6, H2CO and HCN columns derived from three years of ground-based FTIR measurements at Xianghe, China
Abstract. Carbon monoxide (CO), acetylene (C2H2), ethane (C2H6), formaldehyde (H2CO), and hydrogen cyanide (HCN) are important trace gases in the atmosphere. They are highly related to biomass burning, fossil fuel combustion, and biogenic emissions, affecting air quality and climate change. Mid-infrared high spectral resolution solar-absorption spectra are continuously recorded by a Fourier-transform infrared (FTIR) spectrometer (Bruker IFS 125HR) at Xianghe (39.75° N, 116.96° E), China. In this study, we use the SFIT4 code to retrieve these five species from the FTIR spectra measured between June 2018 and November 2021. The retrieval strategies, retrieval information, and uncertainties are presented and discussed. For the first time, the time series, variations, and correlations of these five species are analyzed in North China. The seasonal variations of C2H2 and C2H6 total columns show a maximum in winter-spring and a minimum in autumn, whereas the seasonal variations of H2CO and HCN show a maximum in summer and a minimum in winter. Unlike the other four species, there is almost no seasonal variation of the CO total column. Using the monthly means as the background, the synoptic variations of these species are investigated as well. The FTIR measurements at Xianghe reveal high correlations among these species, indicating that they are affected by common sources. The correlation coefficients (R) between CO and the other four species (C2H2, C2H6, H2CO, and HCN) are between 0.68 and 0.80. The FLEXible PARTicle dispersion model (FLEXPART) v10.4 backward simulations are used to understand the airmass sources observed at Xianghe, and it is found that the high column abundances are coming mainly from local anthropogenic emissions. Using satellite measurements, we show that the boreal forest fire emissions in Russia can lead to enhanced HCN total columns at Xianghe.
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RC1: 'Comment on acp-2022-354', Anonymous Referee #1, 03 Jul 2022
This paper uses the SFIT4 code to retrieve Carbon monoxide (CO), acetylene (C2H2), ethane (C2H6), formaldehyde (H2CO), and hydrogen cyanide (HCN) five species from the FTIR spectra for more than three years and discusses the correlation between them.
The paper is nicely organized and results summarized well (though some minor editorial work needed here and there) but I have a few concerns with the scientific significance and value of this research. Within the NDACC, these five species are conventional gases. There is no improvement or innovation in the inversion algorithm in this study. It seems that the selection of these five gases is that they are in the mid infrared band which is lack of scientific significance. Some key issues:
- In table2, whatâs the reason for different gases with different spectral resolutions, e.g., CO with 0.0035 cm-1 where H2CO, C2H6 with 0.0051 cm-1. How is the spectral band range determined? For TCCON, each inversion window is carefully selected, how is inversion window determined for these five species?
- The author use the optimal estimation method (OEM) for CO and use the Tikhonov L1 method for other four species? Can you give a discussion about the two method and the reason for choosing different method for different species?
- Since Xianghe FTIR measurements compliant with the NDACC-IRWG protocols and the algorithm is available in the published literature, just a brief description is needed here for completeness.
- It seems strange that CO has no seasonal changes. Could you please compare it with CO total column retrieved by TCCON algorithm?
Citation: https://doi.org/10.5194/acp-2022-354-RC1 -
AC1: 'Reply on RC1', minqiang zhou, 14 Jul 2022
The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-354/acp-2022-354-AC1-supplement.pdf
-
RC2: 'Comment on acp-2022-354', Anonymous Referee #2, 23 Jul 2022
- This study was based on the FTIR measurement at Xianghe, China. Using the measurement data, the variation and correlation of CO and some hydrocarbons were examined. The methodology was well prepared and also clearly suggested in this manuscript. All results looks moderately fine.
- But this manuscript does not include the new finding and discriminated feature compared to previous works. In other words, the research motivation looks very weak. The only special motivation of this work is that this study is the first FTIR measurement at Xianghe, China. Probably this can be a good motivation, because there were not much FTIR measurements and related analyses in China, I think. However, this 'first measurement' was not resulted in fresh ideas about the hydrocarbon pattern in China. All results and discussions were too plain. What can we learn more for the hydrocarbon pattern in China using this first FTIR measurement at Xianghe, China?
- In detail, the methodology part looks fine, but this is the thing that we already know. This information (retrieval channel, absorption lines, averaging kernels, etc.) has been much discussed in other previous works. Do we have something new in this manuscript, which was not treated in the previous work?
- In results, the analyses was composed of simple time-series, monthly mean pattern, correlation between CO and other hydrocarbons, back-trajectory pattern, and emission estimation. The performance is not bad, but again, this is just a 'revival' of previous FTIR works. We already have a number of previous studies showing these information in recent 10-20 years (e.g., Zhao et al., 2002; Vigouroux et al., 2012; Viatte et al., 2013; Viatte et al., 2014; Lutsch et al., 2016, etc.). To have another publication, the new finding should be included in this manuscript, which was not discussed in these previous works. Therefore, the 'unique' pattern of CO and hydrocarbon should be provided with this 'first' FTIR measurement at Xianghe, China. That is the expected point, but it is not included in this manuscript.
- Nonetheless, I still would like to put the weight on the meaning of 'first' FTIR measurement at Xianghe, China. This may not the first FTIR measurement in whole China, but based on my knowledge, the 'CO and hydrocarbon' analysis based on Bruker FTIR was very rare in China. It actually relates to the unique meaning of this work. Considering this point, I strongly suggest authors to withdraw this manuscript from ACP, and to submit this manuscript again to AMT (or trasfer from ACP to AMT review process, if possible). I think that the AMT looks much better journal to deal with this manuscript.
- Before the re-submission or transfer, please improve the quality of discussion. Now, most of statements in the result chapter is just a simple reading of graphs, or too typical not including any meaning (e.g., page 18, line 4-6, "Our results show that ... atmospheric vertical stability" => This kind of statement does not have any real meaning. Anybody can say this with any result), or too limited to the small case that is not well generalized (e.g., page 19, line 21-23, " we understand that the drop ... fire emission in the Siberia" => This is just for July and August 2021. Can we generalize this different influence in other years?). Deeper analyses looks very required.
Citation: https://doi.org/10.5194/acp-2022-354-RC2 -
AC2: 'Reply on RC2', minqiang zhou, 29 Aug 2022
The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-354/acp-2022-354-AC2-supplement.pdf
-
AC2: 'Reply on RC2', minqiang zhou, 29 Aug 2022
Status: closed
-
RC1: 'Comment on acp-2022-354', Anonymous Referee #1, 03 Jul 2022
This paper uses the SFIT4 code to retrieve Carbon monoxide (CO), acetylene (C2H2), ethane (C2H6), formaldehyde (H2CO), and hydrogen cyanide (HCN) five species from the FTIR spectra for more than three years and discusses the correlation between them.
The paper is nicely organized and results summarized well (though some minor editorial work needed here and there) but I have a few concerns with the scientific significance and value of this research. Within the NDACC, these five species are conventional gases. There is no improvement or innovation in the inversion algorithm in this study. It seems that the selection of these five gases is that they are in the mid infrared band which is lack of scientific significance. Some key issues:
- In table2, whatâs the reason for different gases with different spectral resolutions, e.g., CO with 0.0035 cm-1 where H2CO, C2H6 with 0.0051 cm-1. How is the spectral band range determined? For TCCON, each inversion window is carefully selected, how is inversion window determined for these five species?
- The author use the optimal estimation method (OEM) for CO and use the Tikhonov L1 method for other four species? Can you give a discussion about the two method and the reason for choosing different method for different species?
- Since Xianghe FTIR measurements compliant with the NDACC-IRWG protocols and the algorithm is available in the published literature, just a brief description is needed here for completeness.
- It seems strange that CO has no seasonal changes. Could you please compare it with CO total column retrieved by TCCON algorithm?
Citation: https://doi.org/10.5194/acp-2022-354-RC1 -
AC1: 'Reply on RC1', minqiang zhou, 14 Jul 2022
The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-354/acp-2022-354-AC1-supplement.pdf
-
RC2: 'Comment on acp-2022-354', Anonymous Referee #2, 23 Jul 2022
- This study was based on the FTIR measurement at Xianghe, China. Using the measurement data, the variation and correlation of CO and some hydrocarbons were examined. The methodology was well prepared and also clearly suggested in this manuscript. All results looks moderately fine.
- But this manuscript does not include the new finding and discriminated feature compared to previous works. In other words, the research motivation looks very weak. The only special motivation of this work is that this study is the first FTIR measurement at Xianghe, China. Probably this can be a good motivation, because there were not much FTIR measurements and related analyses in China, I think. However, this 'first measurement' was not resulted in fresh ideas about the hydrocarbon pattern in China. All results and discussions were too plain. What can we learn more for the hydrocarbon pattern in China using this first FTIR measurement at Xianghe, China?
- In detail, the methodology part looks fine, but this is the thing that we already know. This information (retrieval channel, absorption lines, averaging kernels, etc.) has been much discussed in other previous works. Do we have something new in this manuscript, which was not treated in the previous work?
- In results, the analyses was composed of simple time-series, monthly mean pattern, correlation between CO and other hydrocarbons, back-trajectory pattern, and emission estimation. The performance is not bad, but again, this is just a 'revival' of previous FTIR works. We already have a number of previous studies showing these information in recent 10-20 years (e.g., Zhao et al., 2002; Vigouroux et al., 2012; Viatte et al., 2013; Viatte et al., 2014; Lutsch et al., 2016, etc.). To have another publication, the new finding should be included in this manuscript, which was not discussed in these previous works. Therefore, the 'unique' pattern of CO and hydrocarbon should be provided with this 'first' FTIR measurement at Xianghe, China. That is the expected point, but it is not included in this manuscript.
- Nonetheless, I still would like to put the weight on the meaning of 'first' FTIR measurement at Xianghe, China. This may not the first FTIR measurement in whole China, but based on my knowledge, the 'CO and hydrocarbon' analysis based on Bruker FTIR was very rare in China. It actually relates to the unique meaning of this work. Considering this point, I strongly suggest authors to withdraw this manuscript from ACP, and to submit this manuscript again to AMT (or trasfer from ACP to AMT review process, if possible). I think that the AMT looks much better journal to deal with this manuscript.
- Before the re-submission or transfer, please improve the quality of discussion. Now, most of statements in the result chapter is just a simple reading of graphs, or too typical not including any meaning (e.g., page 18, line 4-6, "Our results show that ... atmospheric vertical stability" => This kind of statement does not have any real meaning. Anybody can say this with any result), or too limited to the small case that is not well generalized (e.g., page 19, line 21-23, " we understand that the drop ... fire emission in the Siberia" => This is just for July and August 2021. Can we generalize this different influence in other years?). Deeper analyses looks very required.
Citation: https://doi.org/10.5194/acp-2022-354-RC2 -
AC2: 'Reply on RC2', minqiang zhou, 29 Aug 2022
The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-354/acp-2022-354-AC2-supplement.pdf
-
AC2: 'Reply on RC2', minqiang zhou, 29 Aug 2022
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