Shipborne measurements of XCO&lt;sub&gt;2&lt;/sub&gt;, XCH&lt;sub&gt;4&lt;/sub&gt;, and XCO above the Pacific Ocean and comparison to CAMS atmospheric analyses and S5P/TROPOMI

Abstract. Measurements of atmospheric column-averaged dry-air mole fractions of carbon dioxide (XCO2), methane (XCH4), and carbon monoxide (XCO) have been collected across the Pacific Ocean during the Measuring Ocean REferences 2 (MORE-2) campaign in June 2019. We deployed a shipborne variant of the EM27/SUN Fourier transform spectrometer (FTS) on board the German R/V Sonne which, during MORE-2, crossed the Pacific Ocean from Vancouver, Canada, to Singapore. Equipped with a specially manufactured fast solar tracker, the FTS operated in direct-sun viewing geometry during the ship cruise reliably delivering solar absorption spectra in the shortwave infrared spectral range (4000 to 11000 cm−1). After filtering and bias correcting the dataset, we report on XCO2, XCH4, and XCO measurements for 22 d along a trajectory that largely aligns with 30∘ N of latitude between 140∘ W and 120∘ E of longitude. The dataset has been scaled to the Total Carbon Column Observing Network (TCCON) station in Karlsruhe, Germany, before and after the MORE-2 campaign through side-by-side measurements. The 1σ repeatability of hourly means of XCO2, XCH4, and XCO is found to be 0.24 ppm, 1.1 ppb, and 0.75 ppb, respectively. The Copernicus Atmosphere Monitoring Service (CAMS) models gridded concentration fields of the atmospheric composition using assimilated satellite observations, which show excellent agreement of 0.52±0.31 ppm for XCO2, 0.9±4.1 ppb for XCH4, and 3.2±3.4 ppb for XCO (mean difference ± SD, standard deviation, of differences for entire record) with our observations. Likewise, we find excellent agreement to within 2.2±6.6 ppb with the XCO observations of the TROPOspheric MOnitoring Instrument (TROPOMI) on the Sentinel-5 Precursor satellite (S5P). The shipborne measurements are accessible at https://doi.org/10.1594/PANGAEA.917240 (Knapp et al., 2020).

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Ship-borne measurements of XCO2, XCH4, and XCO above the Pacific Ocean and comparison to CAMS atmospheric analyses and S5P/TROPOMI

10.5194/essd-2020-132 ◽

2020 ◽

Author(s):

Marvin Knapp ◽

Ralph Kleinschek ◽

Frank Hase ◽

Anna Agustí-Panareda ◽

Antje Inness ◽

...

Keyword(s):

Pacific Ocean ◽

Excellent Agreement ◽

Total Carbon ◽

Solar Absorption ◽

The Pacific ◽

Before And After ◽

Infrared Spectral ◽

Solar Tracker ◽

The Pacific Ocean ◽

Shortwave Infrared

Abstract. Measurements of atmospheric column-averaged dry-air mole fractions of carbon dioxide (XCO2), methane (XCH4), and carbon monoxide (XCO) have been collected across the Pacific ocean during the Measuring Ocean REferences 2 (MORE-2) campaign in June 2019. We deployed a ship-borne variant of the EM27/SUN Fourier Transform Spectrometer (FTS) on board the German research vessel Sonne which, during MORE-2, crossed the Pacific ocean from Vancouver, Canada, to Singapore. Equipped with a specially manufactured fast solar tracker, the FTS operated in direct-sun viewing geometry during the ship cruise reliably delivering solar absorption spectra in the shortwave infrared spectral range (4000 to 11 000 1/cm). After filtering and bias correcting the dataset, we report on XCO2, XCH4, and XCO measurements for 22 days along a trajectory that largely aligns with 30° N of latitude between 140° W and 120° E of longitude. The dataset has been scaled to the Total Carbon Column Observing Network (TCCON) station in Karlsruhe, Germany, before and after the MORE-2 campaign through side-by-side measurements. The precision for hourly means of XCO2, XCH4, and XCO during the campaign is found 0.24 ppm, 1.1 ppb, and 0.75 ppb, respectively. Comparing concentration fields analysed by the Copernicus Atmosphere Monitoring Service (CAMS) to our data, we find excellent agreement of 0.52 ± 0.31 ppm for XCO2, 0.9 ± 4.1 ppb for XCH4, and 3.2 ± 3.4 ppb for XCO (mean difference ± standard deviation of differences for entire record). Likewise, we find excellent agreement to within 2.2 ± 6.6 ppb with the XCO observations of the TROPOspheric MOnitoring Instrument (TROPOMI) on the Sentinel-5 Precursor satellite (S5P). The ship-borne measurements are accessible at https://doi.org/10.1594/PANGAEA.917240 (Knapp et al., 2020).

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Retrieval of xCO2 from ground-based mid-infrared (NDACC) solar absorption spectra and comparison to TCCON

Atmospheric Measurement Techniques ◽

10.5194/amt-9-577-2016 ◽

2016 ◽

Vol 9 (2) ◽

pp. 577-585 ◽

Cited By ~ 6

Author(s):

Matthias Buschmann ◽

Nicholas M. Deutscher ◽

Vanessa Sherlock ◽

Mathias Palm ◽

Thorsten Warneke ◽

...

Keyword(s):

Absorption Spectra ◽

Seasonal Cycle ◽

Total Carbon ◽

Atmospheric Composition ◽

Composition Change ◽

Solar Absorption ◽

Mid Infrared ◽

Infrared Spectral ◽

Ftir Spectrometer ◽

Total Column

Abstract. High-resolution solar absorption spectra, taken within the Network for the Detection of Atmospheric Composition Change Infrared Working Group (NDACC-IRWG) in the mid-infrared spectral region, are used to infer partial or total column abundances of many gases. In this paper we present the retrieval of a column-averaged mole fraction of carbon dioxide from NDACC-IRWG spectra taken with a Fourier transform infrared (FTIR) spectrometer at the site in Ny-Ålesund, Spitsbergen. The retrieved time series is compared to colocated standard TCCON (Total Carbon Column Observing Network) measurements of column-averaged dry-air mole fractions of CO2 (denoted by xCO2). Comparing the NDACC and TCCON retrievals, we find that the sensitivity of the NDACC retrieval is lower in the troposphere (by a factor of 2) and higher in the stratosphere, compared to TCCON. Thus, the NDACC retrieval is less sensitive to tropospheric changes (e.g., the seasonal cycle) in the column average.

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Onboard measurement system of atmospheric carbon monoxide over the Pacific Ocean by voluntary observing ships

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-4-4505-2011 ◽

2011 ◽

Vol 4 (4) ◽

pp. 4505-4537

Author(s):

H. Nara ◽

H. Tanimoto ◽

Y. Nojiri ◽

H. Mukai ◽

T. Machida ◽

...

Keyword(s):

Carbon Monoxide ◽

Pacific Ocean ◽

Measurement System ◽

Ambient Air ◽

The United States ◽

Automated System ◽

Mixing Ratios ◽

The Pacific ◽

Before And After ◽

The Pacific Ocean

Abstract. Long-term monitoring of carbon monoxide (CO) mixing ratios in the atmosphere over the Pacific Ocean is being carried out on commercial cargo vessels participating in the National Institute for Environmental Studies Voluntary Observing Ships program. The program provides a regular platform for measurement of atmospheric CO along four cruising routes: from Japan to Oceania, from Japan to the United States, from Japan to Canada, and from Japan to Southeast Asia. Flask samples are collected during every cruise for subsequent analysis in the laboratory, and in 2005, continuous shipboard CO measurements were initiated on three of the routes. Here, we describe the system we developed for onboard measurement of CO mixing ratios with a commercially available gas filter correlation CO analyzer. The fully automated system measures CO in ambient air, and the detector sensitivity and background signals are calibrated by referencing the measurements to a CO-in-air standard gas (~1 ppmv) and to CO-free air scrubbed with a catalyst, respectively. We examined the artificial production of CO in the high-pressure working gas standards (CO balanced with purified air at ppmv levels) during storage by referencing the measurements to CO standard gases maintained as our primary scale before and after use on the ships. The onboard performance of the continuous CO measurement system was evaluated by comparing its data with data from laboratory analyses of flask samples using gas chromatography with a reduction gas detector. The reasonably good consistency between the two independent measurement methods demonstrated the good performance of both methods over the course of 3–5 yr. The continuous measurement system was more useful than the flask sampling method for regionally polluted air masses, which were often encountered on Southeast Asian cruises.

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