Mapping spectroscopic uncertainties into prospective methane retrieval errors from Sentinel-5 and its precursor

Checa‐Garcia, Ramiro; Landgraf, Jochen; Galli, André; Hase, Frank; Velazco, Voltaire A.; Boudon, Vincent; Alkemade, F.; Butz, A.

doi:10.5194/amt-8-3617-2015

Cited by 20 publications

(17 citation statements)

References 46 publications

(49 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For now, however, we have found that adding the NIR band does not have added value for CH 4 retrievals. Furthermore, inaccuracies in current CH 4 and water vapor spectroscopic parameters could potentially introduce CH 4 retrieval errors as shown by Checa‐Garcia et al (), Frankenberg et al (), and Galli et al (). We see systematic spectral residuals that hint to such spectroscopic errors.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Toward Global Mapping of Methane With TROPOMI: First Results and Intersatellite Comparison to GOSAT

Landgraf

Detmers

et al. 2018

Geophysical Research Letters

Self Cite

250

208

View full text Add to dashboard Cite

The TROPOspheric Monitoring Instrument (TROPOMI), launched on 13 October 2017, aboard the Sentinel‐5 Precursor satellite, measures reflected sunlight in the ultraviolet, visible, near‐infrared, and shortwave infrared spectral range. It enables daily global mapping of key atmospheric species for monitoring air quality and climate. We present the first methane observations from November and December 2017, using TROPOMI radiance measurements in the shortwave infrared band around 2.3 μm. We compare our results with the methane product obtained from the Greenhouse gases Observing SATellite (GOSAT). Although different spectral ranges and retrieval methods are used, we find excellent agreement between the methane products acquired from the two satellites with a mean difference of 13.6 ppb, standard deviation of 19.6 ppb, and Pearson's correlation coefficient of 0.95. Our preliminary results capture the latitudinal gradient and show expected regional enhancements, for example, in the African Sudd wetlands, with much more detail than has been observed before.

show abstract

Section: Conclusion and Discussionmentioning

confidence: 99%

Toward Global Mapping of Methane With TROPOMI: First Results and Intersatellite Comparison to GOSAT

Landgraf

Detmers

et al. 2018

Geophysical Research Letters

Self Cite

250

208

View full text Add to dashboard Cite

show abstract

“…Another relevant source of errors to the CH 4 data product could be spectroscopic errors. This has been studied in detail by Galli et al (2012) and Checa-Garcia et al (2015). Note that a study is ongoing to improve the spectroscopic data for TROPOMI's SWIR spectral range (Loos et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

The operational methane retrieval algorithm for TROPOMI

et al. 2016

Self Cite

View full text Add to dashboard Cite

Abstract. This work presents the operational methane retrieval algorithm for the Sentinel 5 Precursor (S5P) satellite and its performance tested on realistic ensembles of simulated measurements. The target product is the columnaveraged dry air volume mixing ratio of methane (XCH 4 ), which will be retrieved simultaneously with scattering properties of the atmosphere. The algorithm attempts to fit spectra observed by the shortwave and near-infrared channels of the TROPOspheric Monitoring Instrument (TROPOMI) spectrometer aboard S5P.The sensitivity of the retrieval performance to atmospheric scattering properties, atmospheric input data and instrument calibration errors is evaluated. In addition, we investigate the effect of inhomogeneous slit illumination on the instrument spectral response function. Finally, we discuss the cloud filters to be used operationally and as backup.We show that the required accuracy and precision of < 1 % for the XCH 4 product are met for clear-sky measurements over land surfaces and after appropriate filtering of difficult scenes. The algorithm is very stable, having a convergence rate of 99 %. The forward model error is less than 1 % for about 95 % of the valid retrievals. Model errors in the input profile of water do not influence the retrieval outcome noticeably. The methane product is expected to meet the requirements if errors in input profiles of pressure and temperature remain below 0.3 % and 2 K, respectively. We further find that, of all instrument calibration errors investigated here, our retrievals are the most sensitive to an error in the instrument spectral response function of the shortwave infrared channel.

show abstract

“…Such "physics-based" methods have been developed for space-based CO 2 and CH 4 measurements from SCIAMACHY, GOSAT and the Orbiting Carbon Observatory (OCO); see e.g. Connor et al (2008); Butz et al (2009) ;Reuter et al (2010); O'Dell et al (2012). The physics-based methods make use of the oxygen (O 2 ) A-band in the near-infrared (NIR) around 760 nm and absorption bands of the target absorber in the SWIR spectral range.…”

Section: Introductionmentioning

confidence: 99%

Author's reply to Anonymous Referee #1

Hu¹

2016

View full text Add to dashboard Cite

This work presents the operational methane retrieval algorithm for the Sentinel 5 Precursor (S5P) satellite and its performance tested on realistic ensembles of simulated measurements. The target product is the columnaveraged dry air volume mixing ratio of methane (XCH 4 ), which will be retrieved simultaneously with scattering properties of the atmosphere. The algorithm attempts to fit spectra observed by the shortwave and near-infrared channels of the TROPOspheric Monitoring Instrument (TROPOMI) spectrometer aboard S5P.The sensitivity of the retrieval performance to atmospheric scattering properties, atmospheric input data and instrument calibration errors is evaluated. In addition, we investigate the effect of inhomogeneous slit illumination on the instrument spectral response function. Finally, we discuss the cloud filters to be used operationally and as backup.We show that the required accuracy and precision of < 1 % for the XCH 4 product are met for clear-sky measurements over land surfaces and after appropriate filtering of difficult scenes. The algorithm is very stable, having a convergence rate of 99 %. The forward model error is less than 1 % for about 95 % of the valid retrievals. Model errors in the input profile of water do not influence the retrieval outcome noticeably. The methane product is expected to meet the requirements if errors in input profiles of pressure and temperature remain below 0.3 % and 2 K, respectively. We further find that, of all instrument calibration errors investigated here, our retrievals are the most sensitive to an error in the instrument spectral response function of the shortwave infrared channel.Published by Copernicus Publications on behalf of the European Geosciences Union.

show abstract

Mapping spectroscopic uncertainties into prospective methane retrieval errors from Sentinel-5 and its precursor

Cited by 20 publications

References 46 publications

Toward Global Mapping of Methane With TROPOMI: First Results and Intersatellite Comparison to GOSAT

Toward Global Mapping of Methane With TROPOMI: First Results and Intersatellite Comparison to GOSAT

The operational methane retrieval algorithm for TROPOMI

Author's reply to Anonymous Referee #1

Contact Info

Product

Resources

About