The Total Carbon Column Observing Network

A global network of ground-based Fourier transform spectrometers has been founded to remotely measure column abundances of CO 2 , CO, CH 4 , N 2 O and other molecules that absorb in the near-infrared. These measurements are directly comparable with the near-infrared total column measurements from space-based instruments. With stringent requirements on the instrumentation, acquisition procedures, data processing and calibration, the Total Carbon Column Observing Network (TCCON) achieves an accuracy and precision in total column measurements that is unprecedented for remote-sensing observations (better than 0.25% for CO 2 ). This has enabled carbon-cycle science investigations using the TCCON dataset, and allows the TCCON to provide a link between satellite measurements and the extensive ground-based in situ network.

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Retrieval of atmospheric CH<sub>4</sub> vertical information from TCCON FTIR spectra

10.5194/amt-2019-94 ◽

2019 ◽

Author(s):

Minqiang Zhou ◽

Bavo Langerock ◽

Mahesh Kumar Sha ◽

Nicolas Kumps ◽

Christian Hermans ◽

...

Keyword(s):

Mole Fraction ◽

Distinct Species ◽

Satellite Observations ◽

Total Carbon ◽

Systematic Uncertainties ◽

Time Period ◽

Accuracy And Precision ◽

Retrieval Software ◽

Total Column

Abstract. TCCON (Total Carbon Column Observing Network) column-averaged dry air mole fraction of CH4 (XCH4) measurements have been widely used to validate satellite observations and to estimate model simulations. The GGG2014 code is the standard TCCON retrieval software performing a profile scaling retrieval. In order to obtain several vertical information in addition to total column, in this study, the SFIT4 retrieval code is applied to retrieve CH4 mole fraction vertical profile using TCCON spectra (SFIT4TCCON) at six sites (Ny-Ålesund, Sodankylä, Bialystok, Bremen, Orléans and St Denis) during the time period of 2016−2017. The retrieval strategy of SFIT4TCCON is investigated. The degree of freedom for signal of the SFIT4TCCON retrieval is about 2.4, with two distinct species of information in the troposphere and in the stratosphere. The averaging kernel and error budget of the SFIT4TCCON retrieval are presented. The data accuracy and precision of the SFIT4TCCON retrievals, including the total column and two partial columns (in the troposphere and stratosphere), are estimated by TCCON standard retrievals, ground-based in situ measurements, ACE-FTS satellite observations, TCCON proxy data and AirCore measurements. By comparison against TCCON standard retrievals, it is found that the retrieval uncertainty of SFIT4TCCON XCH4 is similar to that of TCCON standard retrievals with the systematic uncertainty within 0.35 % and the random uncertainty about 0.5 %. The tropospheric and stratospheric XCH4 from SFIT4TCCON retrievals are assessed by comparing with AirCore measurements at Sodankylä, and there is a 1.2 % overestimation in the SFIT4TCCON tropospheric XCH4 and a 4.0 % underestimation in the SFIT4TCCON stratospheric XCH4, which are within the systematic uncertainties of SFIT4TCCON retrieved partial columns in the troposphere and stratosphere, respectively.

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Calibration of TCCON column-averaged CO<sub>2</sub>: the first aircraft campaign over European TCCON sites

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-14541-2011 ◽

2011 ◽

Vol 11 (5) ◽

pp. 14541-14582 ◽

Cited By ~ 3

Author(s):

J. Messerschmidt ◽

M. C. Geibel ◽

T. Blumenstock ◽

H. Chen ◽

N. M. Deutscher ◽

...

Keyword(s):

Fourier Transform ◽

A Priori ◽

High Accuracy ◽

Calibration Factor ◽

Total Carbon ◽

Fourier Transform Spectrometer ◽

Calibration And Validation ◽

Total Column ◽

Better Than

Abstract. The Total Carbon Column Observing Network (TCCON) is a ground-based network of Fourier Transform Spectrometer (FTS) sites around the globe, where the column abundances of CO2, CH4, N2O, CO and O2 are measured. CO2 is constrained with a precision better than 0.25 %. To achieve a similarly high accuracy, calibration to World Meteorological Organization (WMO) standards is required. This paper introduces the first aircraft calibration campaign of five European TCCON sites and a mobile FTS instrument. A series of WMO standards in-situ profiles were obtained over European TCCON sites via aircraft and compared with retrievals of CO2 column amounts from the TCCON instruments. The results of the campaign show that the FTS measurements are consistently biased 1.0 % ± 0.2 % low with respect to WMO standards, in agreement with previous TCCON calibration campaigns. The standard a priori profile for the TCCON FTS retrievals is shown to not add a bias. The same calibration factor is generated using aircraft profiles as a priori and with the TCCON standard a priori. With a calibration to WMO standards, the highly precise TCCON CO2 measurements of total column concentrations provide a suitable database for the calibration and validation of nadir-viewing satellites.

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Calibration of TCCON column-averaged CO<sub>2</sub>: the first aircraft campaign over European TCCON sites

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-10765-2011 ◽

2011 ◽

Vol 11 (21) ◽

pp. 10765-10777 ◽

Cited By ~ 101

Author(s):

J. Messerschmidt ◽

M. C. Geibel ◽

T. Blumenstock ◽

H. Chen ◽

N. M. Deutscher ◽

...

Keyword(s):

Fourier Transform ◽

A Priori ◽

High Accuracy ◽

Calibration Factor ◽

Total Carbon ◽

Fourier Transform Spectrometer ◽

Calibration And Validation ◽

Total Column ◽

Better Than

Abstract. The Total Carbon Column Observing Network (TCCON) is a ground-based network of Fourier Transform Spectrometer (FTS) sites around the globe, where the column abundances of CO2, CH4, N2O, CO and O2 are measured. CO2 is constrained with a precision better than 0.25% (1-σ). To achieve a similarly high accuracy, calibration to World Meteorological Organization (WMO) standards is required. This paper introduces the first aircraft calibration campaign of five European TCCON sites and a mobile FTS instrument. A series of WMO standards in-situ profiles were obtained over European TCCON sites via aircraft and compared with retrievals of CO2 column amounts from the TCCON instruments. The results of the campaign show that the FTS measurements are consistently biased 1.1% ± 0.2% low with respect to WMO standards, in agreement with previous TCCON calibration campaigns. The standard a priori profile for the TCCON FTS retrievals is shown to not add a bias. The same calibration factor is generated using aircraft profiles as a priori and with the TCCON standard a priori. With a calibration to WMO standards, the highly precise TCCON CO2 measurements of total column concentrations provide a suitable database for the calibration and validation of nadir-viewing satellites.

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Remote Sensing Measurements of Carbon Dioxide and Methane over Northern Finland

10.5194/egusphere-egu21-13073 ◽

2021 ◽

Author(s):

Rigel Kivi ◽

Juha Hatakka ◽

Pauli Heikkinen ◽

Tuomas Laurila ◽

Hannakaisa Lindqvist ◽

...

Keyword(s):

Remote Sensing ◽

Carbon Dioxide ◽

Near Infrared ◽

Total Carbon ◽

Measurement Scales ◽

Time Period ◽

Infrared Spectral ◽

Gas Measurement

<p>Remote sensing measurements of carbon dioxide and methane at the Sodankyl&#228; facility in northern Finland cover a 12-year time period. The measurements have been taken by a Fourier Transform Spectrometer (FTS), operating in the near-infrared spectral region.&#160; The Sodankyl&#228; site is participating in the Total Carbon Column Observing Network (TCCON). Here we present long-term measurements of column-averaged, dry-air mole fractions of carbon dioxide and methane and comparisons with satellite borne measurements. The relevant satellite missions include the TROPOspheric Monitoring Instrument (TROPOMI) on board of the Copernicus Sentinel-5 Precursor satellite, the Orbiting Carbon Observatory-2 (OCO-2) and the Greenhouse Gases Observing Satellite (GOSAT). We have performed AirCore observations in the vicinity of the TCCON instrument at Sodankyl&#228; during all seasons. AirCore measurements are directly related to the World Meteorological Organization in situ trace gas measurement scales. The AirCore data are used in this study to provide comparisons with remote sensing retrievals.</p>

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Early Comparison of OCO-3 XCO2 Measurements with TCCON

10.5194/egusphere-egu2020-9844 ◽

2020 ◽

Author(s):

Matthaeus Kiel ◽

Joshua Laughner ◽

Annmarie Eldering ◽

Brendan Fisher ◽

Thomas Kurosu ◽

...

Keyword(s):

Near Infrared ◽

Space Station ◽

Total Carbon ◽

Global Network ◽

Kennedy Space Center ◽

The Earth ◽

Target Mode ◽

Infrared Spectral ◽

Kennedy Space

<p>The Orbiting Carbon Observatory-3 (OCO-3) was successfully launched on May 4, 2019 from Kennedy Space Center via a Space-X Falcon 9. One week later, the instrument was installed as an external payload on the International Space Station (ISS). OCO-3 extends NASA&#8217;s study of carbon and measures the dry-air mole fraction of column carbon dioxide (XCO2) in the Earth&#8217;s atmosphere from space.</p><p>These space-based measurements are compared to ground-based observations from the Total Carbon Column Observing Network (TCCON). TCCON is a global network of high-resolution ground-based Fourier Transform Spectrometers that records spectra of the sun in the near-infrared spectral region. From these spectra, accurate and precise column-averaged abundances of atmospheric constituents including CO2 are retrieved. TCCON data are tied to the WMO scale and serve as the link between calibrated surface in situ measurements and OCO-3 measurements.</p><p>OCO-3&#8217;s agile 2-D pointing mirror assembly (PMA) allows the instrument to stare at a TCCON station as it passes overhead - providing information about the quality, biases, and errors in the OCO-3 data. Here, we show early comparisons between the OCO-3 XCO2 dataset collected during target mode observations and coincident TCCON measurements and discuss site-dependent biases and its potential origins.</p>

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Toward CO2 and CH4 measurements by ground-based observations of surface-scattered sunlight

10.5194/egusphere-egu21-7569 ◽

2021 ◽

Author(s):

Benedikt Hemmer ◽

Christin Proß ◽

Stanley P. Sander ◽

Thomas J. Pongetti ◽

Zhao-Cheng Zeng ◽

...

Keyword(s):

Los Angeles ◽

Urban Areas ◽

Near Infrared ◽

Chem Phys ◽

Retrieval Algorithm ◽

Los Angeles Basin ◽

Satellite Measurements ◽

Precise Knowledge ◽

Extended Sources

<div> <div>Precise knowledge of sources and sinks in the carbon cycle is desired to understand its sensitivity to climate change and to account and verify man-made emissions. In this context, extended sources like urban areas play an important role. While in-situ measurements of carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>) are highly accurate but localized, satellites measure column-integrated concentrations over an extended footprint. The CLARS-FTS [1, 2] stationed at the Mt. Wilson observatory looking downward into the Los Angeles basin has pioneered an innovative measurement technique that fills the sensitivity gap between in-situ and satellite measurements. The technique enables mapping the urban greenhouse gas concentration fields by collecting spectra of ground scattered sunlight and scanning through the region.</div> <div>&#160;</div> <div>Here, we report on progress developing a portable setup for a CLARS-FTS-like measurement geometry. The instrument is based on the EM27/SUN FTS with a modified pointing technique and a more sensitive detector. The retrieval algorithm is based on the RemoTeC software, previously employed for solar backscatter satellite measurements. We discuss first steps in terms of instrument performance and retrieval exercises. For the latter, we have carried out simulations on how the neglect of scattering by the retrieval affects the retrieved boundary layer concentrations of CO<sub>2</sub> and CH<sub>4</sub> for an ensemble of hypothetical scenes with variable complexity in aeorsol loadings and viewing geometry. We also report on a test to apply RemoTeC to a small set of CLARS-FTS spectra collected throughout the Los Angeles basin.</div> <div>&#160;</div> <div><em>References</em></div> <div>[1] Fu, D. et al., 2014: Near-infrared remote sensing of Los Angeles trace gas distributions from a mountaintop site, Atmos. Meas. Tech., 7, 713&#8211;729, https://doi.org/10.5194/amt-7-713-2014</div> [2] Wong, K. W. et al., 2015: Mapping CH4 : CO2 ratios in Los Angeles with CLARS-FTS from Mount Wilson, California, Atmos. Chem. Phys., 15, 241&#8211;252, https://doi.org/10.5194/acp-15-241-2015</div>

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Comparisons between SCIAMACHY and ground-based FTIR data for total columns of CO, CH<sub>4</sub>, CO<sub>2</sub> and N<sub>2</sub>O

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-1953-2006 ◽

2006 ◽

Vol 6 (7) ◽

pp. 1953-1976 ◽

Cited By ~ 85

Author(s):

B. Dils ◽

M. De Mazière ◽

J. F. Müller ◽

T. Blumenstock ◽

M. Buchwitz ◽

...

Keyword(s):

Near Infrared ◽

Polynomial Interpolation ◽

Global Network ◽

Target Species ◽

Time Period ◽

Order Polynomial ◽

Temporal And Spatial ◽

The Individual ◽

Near Future ◽

Total Column

Abstract. Total column amounts of CO, CH4, CO2 and N2O retrieved from SCIAMACHY nadir observations in its near-infrared channels have been compared to data from a ground-based quasi-global network of Fourier-transform infrared (FTIR) spectrometers. The SCIAMACHY data considered here have been produced by three different retrieval algorithms, WFM-DOAS (version 0.5 for CO and CH4 and version 0.4 for CO2 and N2O), IMAP-DOAS (version 1.1 and 0.9 (for CO)) and IMLM (version 6.3) and cover the January to December 2003 time period. Comparisons have been made for individual data, as well as for monthly averages. To maximize the number of reliable coincidences that satisfy the temporal and spatial collocation criteria, the SCIAMACHY data have been compared with a temporal 3rd order polynomial interpolation of the ground-based data. Particular attention has been given to the question whether SCIAMACHY observes correctly the seasonal and latitudinal variability of the target species. The present results indicate that the individual SCIAMACHY data obtained with the actual versions of the algorithms have been significantly improved, but that the quality requirements, for estimating emissions on regional scales, are not yet met. Nevertheless, possible directions for further algorithm upgrades have been identified which should result in more reliable data products in a near future.

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Retrieval of atmospheric CH<sub>4</sub> vertical information from ground-based FTS near-infrared spectra

Atmospheric Measurement Techniques ◽

10.5194/amt-12-6125-2019 ◽

2019 ◽

Vol 12 (11) ◽

pp. 6125-6141 ◽

Cited By ~ 3

Author(s):

Minqiang Zhou ◽

Bavo Langerock ◽

Mahesh Kumar Sha ◽

Nicolas Kumps ◽

Christian Hermans ◽

...

Keyword(s):

Fourier Transform ◽

Mole Fraction ◽

Atmospheric Chemistry ◽

Near Infrared ◽

Satellite Observations ◽

Total Carbon ◽

Fourier Transform Spectrometer ◽

Aircraft Measurements ◽

Retrieval Software ◽

Total Column

Abstract. The Total Carbon Column Observing Network (TCCON) column-averaged dry air mole fraction of CH4 (XCH4) measurements have been widely used to validate satellite observations and to estimate model simulations. The GGG2014 code is the standard TCCON retrieval software used in performing a profile scaling retrieval. In order to obtain several vertical pieces of information in addition to the total column, in this study, the SFIT4 retrieval code is applied to retrieve the CH4 mole fraction vertical profile from the Fourier transform spectrometer (FTS) spectrum at six sites (Ny-Ålesund, Sodankylä, Bialystok, Bremen, Orléans and St Denis) during the time period of 2016–2017. The retrieval strategy of the CH4 profile retrieval from ground-based FTS near-infrared (NIR) spectra using the SFIT4 code (SFIT4NIR) is investigated. The degree of freedom for signal (DOFS) of the SFIT4NIR retrieval is about 2.4, with two distinct pieces of information in the troposphere and in the stratosphere. The averaging kernel and error budget of the SFIT4NIR retrieval are presented. The data accuracy and precision of the SFIT4NIR retrievals, including the total column and two partial columns (in the troposphere and stratosphere), are estimated by TCCON standard retrievals, ground-based in situ measurements, Atmospheric Chemistry Experiment – Fourier Transform Spectrometer (ACE-FTS) satellite observations, TCCON proxy data and AirCore and aircraft measurements. By comparison against TCCON standard retrievals, it is found that the retrieval uncertainty of SFIT4NIR XCH4 is similar to that of TCCON standard retrievals with systematic uncertainty within 0.35 % and random uncertainty of about 0.5 %. The tropospheric and stratospheric XCH4 from SFIT4NIR retrievals are assessed by comparison with AirCore and aircraft measurements, and there is a 1.0 ± 0.3 % overestimation in the SFIT4NIR tropospheric XCH4 and a 4.0 ± 2.0 % underestimation in the SFIT4NIR stratospheric XCH4, which are within the systematic uncertainties of SFIT4NIR-retrieved partial columns in the troposphere and stratosphere respectively.

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