Tropospheric CH&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt; signals as observed by NDACC FTIR at   globally distributed sites and comparison to GAW surface in-situ   measurements

Sepúlveda, Eliezer; Schneider, Mat­thias; Hase, Frank; Barthlott, Sabine; Dubravica, Darko; García, O. E.; Gómez-Peláez, Ángel J.; González, Y.; Guerra, J. C.; Gisi, M.; Kohlhepp, R.; Dohe, S.; Blumenstock, Thomas; Strong, Kimberly; Weaver, Dan; Palm, Mathias; Sadeghi, Alireza; Deutscher, Nicholas M.; Warneke, Thorsten; Notholt, Justus; Jones, Nicholas; Griffith, David; Smale, Dan; Brailsford, Gordon; Robinson, John; Meinhardt, F.; Steinbacher, Martin; Aalto, Tuula; Worthy, Doug

doi:10.5194/amtd-7-633-2014

Cited by 3 publications

(2 citation statements)

References 37 publications

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“…Below the (approximate) tropopause altitude, we assume that CH 4 is rather well mixed and the prior profile has approximately the correct shape at least. In a recent CH 4 retrieval paper by Sepúlveda et al [] the authors describe typical CH 4 signals between 0 and 25 km and have a similar treatment of the variability than we have. However, they also consider possible CH 4 enhancement on the ground level, a feature that we do not take into account.…”

Section: Ch4 Profile Retrievalmentioning

confidence: 99%

Retrieval of atmospheric CH₄profiles from Fourier transform infrared data using dimension reduction and MCMC

Tukiainen

Railo

Laine

et al. 2016

J. Geophys. Res. Atmos.

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We introduce an inversion method that uses dimension reduction for the retrieval of atmospheric methane (CH4) profiles. Uncertainty analysis is performed using the Markov chain Monte Carlo (MCMC) statistical estimation. These techniques are used to retrieve CH4 profiles from the ground‐based spectral measurements by the Fourier Transform Spectrometer (FTS) instrument at Sodankylä (67.4°N, 26.6°E), Northern Finland. The Sodankylä FTS is part of the Total Carbon Column Observing Network (TCCON), a global network that observes solar spectra in near‐infrared wavelengths. The high spectral resolution of the data provides approximately 3 degrees of freedom about the vertical structure of CH4 between around 0 and 40 km. We reduce the dimension of the inverse problem by using principal component analysis. Smooth and realistic profiles are sought by estimating three parameters for the profile shape. We use Bayesian framework with adaptive MCMC to better characterize the full posterior distribution of the solution and uncertainties related to the retrieval. The retrieved profiles are validated against in situ AirCore soundings which provide an accurate reference up to 20–30 km. The method is presented in a general form, so that it can easily be adapted for other applications, such as different trace gases or satellite‐borne measurements where more accurate profile information and better analysis of the uncertainties would be highly valuable.

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Section: Ch4 Profile Retrievalmentioning

confidence: 99%

Retrieval of atmospheric CH₄profiles from Fourier transform infrared data using dimension reduction and MCMC

Tukiainen

Railo

Laine

et al. 2016

J. Geophys. Res. Atmos.

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“…This is also true for parameter DD. Estimated aircraft-based XCH 4 values are subject to uncertainties attributable to the assumed CH 4 profile (e.g., Sepúlveda et al 2014). The uncertainty of XCH 4 arises from the accuracy of climatology of CH 4 in the stratosphere, tropopause height, temperature profiles, and CH 4 in the surface layer.…”

Section: Comparison Between Gosatmentioning

confidence: 99%

Comparison of GOSAT SWIR and Aircraft Measurements of XCH<sub>4</sub> over West Siberia

Ono

Hayashida

Sugita

et al. 2015

SOLA

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We investigated the validity of column-averaged dry air mole fractions of methane (XCH 4 : V02.21) retrieved from shortwave infrared (SWIR) spectra obtained by Greenhouse gases Observing SATellite (GOSAT) over Siberia, which is known as a major source area of methane (CH 4 ). We compared the GOSAT XCH 4 dataset with aircraft measurements of XCH 4 that have been collected in Novosibirsk and Surgut, West Siberia since the 1990s. The average difference between the GOSAT XCH 4 and aircraft-based XCH 4 was −1.0 ± 22.0 ppb in Novosibirsk and −0.4 ± 14.8 ppb in Surgut when we selected appropriate data pairs. These results indicate that GOSAT XCH 4 data obtained over West Siberia is consistent with aircraft measurements and assure the reliability of the GOSAT XCH 4 product for scientific analysis.

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Derivation of tropospheric methane from TCCON CH<sub>4</sub> and HF total column observations

Saad¹,

Wunch²,

Toon³

et al. 2014

Preprint

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Abstract. The Total Carbon Column Observing Network (TCCON) is a global ground-based network of Fourier transform spectrometers that produce precise measurements of column-averaged dry-air mole fractions of atmospheric methane (CH4). Temporal variability in the total column of CH4 due to stratospheric dynamics obscures fluctuations and trends driven by tropospheric transport and local sources and sinks. We remove the contribution of stratospheric variability from the total column average by subtracting an estimate of the stratospheric CH4 derived from simultaneous measurements of hydrogen fluoride (HF). HF provides a proxy for stratospheric CH4 because it resides solely in the stratosphere, has a nearly linear inverse relationship with stratospheric CH4, and is measured at most TCCON stations. The stratospheric partial column of CH4 is calculated as a function of the zonal and annual trends in the relationship between CH4 and HF in the stratosphere, which we determine from ACE-FTS satellite data. We also explicitly take into account the CH4 column averaging kernel to estimate the contribution of stratospheric CH4 to the total column. The resulting tropospheric CH4 columns are consistent with in situ aircraft measurements and augment existing observations in the troposphere.

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Tropospheric CH<sub>4</sub> signals as observed by NDACC FTIR at globally distributed sites and comparison to GAW surface in-situ measurements

Cited by 3 publications

References 37 publications

Retrieval of atmospheric CH₄profiles from Fourier transform infrared data using dimension reduction and MCMC

Retrieval of atmospheric CH₄profiles from Fourier transform infrared data using dimension reduction and MCMC

Comparison of GOSAT SWIR and Aircraft Measurements of XCH<sub>4</sub> over West Siberia

Derivation of tropospheric methane from TCCON CH<sub>4</sub> and HF total column observations

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Tropospheric CH&lt;sub&gt;4&lt;/sub&gt; signals as observed by NDACC FTIR at globally distributed sites and comparison to GAW surface in-situ measurements

Cited by 3 publications

References 37 publications

Retrieval of atmospheric CH4profiles from Fourier transform infrared data using dimension reduction and MCMC

Retrieval of atmospheric CH4profiles from Fourier transform infrared data using dimension reduction and MCMC

Comparison of GOSAT SWIR and Aircraft Measurements of XCH<sub>4</sub> over West Siberia

Derivation of tropospheric methane from TCCON CH&lt;sub&gt;4&lt;/sub&gt; and HF total column observations

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Tropospheric CH<sub>4</sub> signals as observed by NDACC FTIR at globally distributed sites and comparison to GAW surface in-situ measurements

Retrieval of atmospheric CH₄profiles from Fourier transform infrared data using dimension reduction and MCMC

Retrieval of atmospheric CH₄profiles from Fourier transform infrared data using dimension reduction and MCMC

Derivation of tropospheric methane from TCCON CH<sub>4</sub> and HF total column observations