References of "Lejeune, Bernard"
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See detailGaz à effet de serre indirects et qualité de l'air aux latitudes moyennes de l'hémisphère nord : tendances à long terme et variabilité déduites de télémesures effectuées au Jungfraujoch (Alpes suisses, 3580 m)
Franco, Bruno ULg; Bader, Whitney ULg; Lejeune, Bernard ULg et al

Conference (2015, July 01)

Indirect greenhouse gases and air quality at Northern Hemisphere mid-latitudes: long-term trends and variability derived from ground-based remote sensing at Jungfraujoch (Swiss Alps, 3580 m a.s.l.). We ... [more ▼]

Indirect greenhouse gases and air quality at Northern Hemisphere mid-latitudes: long-term trends and variability derived from ground-based remote sensing at Jungfraujoch (Swiss Alps, 3580 m a.s.l.). We present an overview of recent investigations conducted by the Solar and Atmospheric Physics Infrared Group at the University of Liège and dedicated to the long-term monitoring of atmospheric gases with an indirect greenhouse effect and affecting air quality at Northern Hemisphere mid-latitudes. Gas concentrations are derived from high-resolution solar spectra recorded at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.), using Fourier transform infrared spectrometers. Time series obtained from these observations, along with satellite measurements and simulations from numerical models, allow for the study of both variability and recent evolution of these species and are critical for air quality monitoring and understanding climate changes. [less ▲]

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See detailInvestigation of the consistency of the recent CH4 increase derived from NDACC-FTIR, ACE-FTS and GEOS-Chem
Bader, Whitney ULg; Conway, Stephanie; Strong, Kim et al

Conference (2015, May 21)

We present an update on the status of the recent methane increase study based on six FTIR ground-based sites, ACE-FTS satellite occultations and GEOS-Chem simulation.

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See detailUse of GEOS-Chem for the interpretation of long-term FTIR measurements at the Jungfraujoch and other NDACC sites
Mahieu, Emmanuel ULg; Bovy, Benoît ULg; Bader, Whitney ULg et al

Poster (2015, May 04)

We present recent and ongoing investigations using 3D CTM GEOS-Chem model simulations for the interpretation of long-term FTIR measurements performed at selected NDACC sites.

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See detailRetrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations
Franco, Bruno ULg; Hendrick, François; Van Roozendael, Michel et al

in Atmospheric Measurement Techniques (2015), 8

As an ubiquitous product of the oxidation of many volatile organic compounds (VOCs), formaldehyde (HCHO) plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation ... [more ▼]

As an ubiquitous product of the oxidation of many volatile organic compounds (VOCs), formaldehyde (HCHO) plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation pathways leading to the formation of tropospheric ozone and secondary organic aerosols. In this study, HCHO profiles have been successfully retrieved from ground-based Fourier transform infrared (FTIR) solar spectra and UV-visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) scans recorded during the July 2010–December 2012 time period at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580m a.s.l.). Analysis of the retrieved products has revealed different vertical sensitivity between both remote sensing techniques. Furthermore, HCHO amounts simulated by two state-of-the-art chemical transport models (CTMs), GEOSChem and IMAGES v2, have been compared to FTIR total columns and MAX-DOAS 3.6–8 km partial columns, accounting for the respective vertical resolution of each ground-based instrument. Using the CTM outputs as the intermediate, FTIR and MAX-DOAS retrievals have shown consistent seasonal modulations of HCHO throughout the investigated period, characterized by summertime maximum and wintertime minimum. Such comparisons have also highlighted that FTIR and MAX-DOAS provide complementary products for the HCHO retrieval above the Jungfraujoch station. Finally, tests have revealed that the updated IR parameters from the HITRAN 2012 database have a cumulative effect and significantly decrease the retrieved HCHO columns with respect to the use of the HITRAN 2008 compilation. [less ▲]

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See detailHalogenated source gases measured by FTIR at the Jungfraujoch station: updated trends and new target species
Mahieu, Emmanuel ULg; Bader, Whitney ULg; Bovy, Benoît ULg et al

in Geophysical Research Abstracts (2015, April 13), 17

In this contribution, we present decadal time series of halogenated source gases monitored at the high altitude station of the Jungfraujoch (46.5°N, 8°E, 3580 m asl) with Fourier Transform Infared (FTIR ... [more ▼]

In this contribution, we present decadal time series of halogenated source gases monitored at the high altitude station of the Jungfraujoch (46.5°N, 8°E, 3580 m asl) with Fourier Transform Infared (FTIR) spectrometers, within the framework of the Network for the Detection of Atmospheric Composition Change. Total column trends presented in previous studies for CFC-11, -12 and HCFC-22, CCl4, HCFC-142b, CF4 and SF6 will be updated using the latest available Jungfraujoch solar observations. Investigations dealing with the definition of approaches to retrieve additional halogenated source gases from FTIR spectra will also be evoked. Our trend results will be critically discussed and compared with measurements performed in the northern hemisphere by the in situ networks. [less ▲]

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See detailRetrieval of ethane from ground-based FTIR solar spectra using improved spectroscopy: recent burden increase above Jungfraujoch
Franco, Bruno ULg; Bader, Whitney ULg; Toon, G. C. et al

in Journal of Quantitative Spectroscopy & Radiative Transfer (2015), 160(C), 36-49

An improved spectroscopy is used to implement and optimize the retrieval strategy of ethane (C2H6) from ground-based Fourier Transform Infrared (FTIR) solar spectra recorded at the high-altitude station ... [more ▼]

An improved spectroscopy is used to implement and optimize the retrieval strategy of ethane (C2H6) from ground-based Fourier Transform Infrared (FTIR) solar spectra recorded at the high-altitude station of Jungfraujoch (Swiss Alps, 46.5° N, 8.0° E, 3580m a.s.l.). The improved spectroscopic parameters include C2H6 pseudo-lines in the 2720-3100 cm-1 range and updated line parameters for methyl chloride and ozone. These improved spectroscopic parameters allow for substantial reduction of the fitting residuals as well as enhanced information content. They also contribute to limiting oscillations responsible for ungeophysical negative mixing ratio profiles. This strategy has been successfully applied to the Jungfraujoch solar spectra available from 1994 onwards. The resulting time series is compared with C2H6 total columns simulated by the state-of-the-art chemical transport model GEOS-Chem. Despite very consistent seasonal cycles between both data sets, a negative systematic bias relative to the FTIR observations suggests that C2H6 emissions are underestimated in the current inventories implemented in GEOS-Chem. Finally, C2H6 trends are derived from the FTIR time series, revealing a statistically-significant sharp increase of the C2H6 burden in the remote atmosphere above Jungfraujoch since 2009. Evaluating cause of this change in the C2H6 burden, which may be related to the recent massive growth of shale gas exploitation in North America, is of primary importance for atmospheric composition and air quality in the Northern Hemisphere. [less ▲]

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See detailUsing XCO2 retrievals for assessing the long-term consistency of NDACC/FTIR data sets
Barthlott, S; Schneider, M; Hase, F et al

in Atmospheric Measurement Techniques (2015), 8

Within the NDACC (Network for the Detection of Atmospheric Composition Change), more than 20 FTIR (Fourier-transform infrared) spectrometers, spread worldwide, provide long-term data records of many ... [more ▼]

Within the NDACC (Network for the Detection of Atmospheric Composition Change), more than 20 FTIR (Fourier-transform infrared) spectrometers, spread worldwide, provide long-term data records of many atmospheric trace gases. We present a method that uses measured and modelled XCO2 for assessing the consistency of these NDACC data records. Our XCO2 retrieval setup is kept simple so that it can easily be adopted for any NDACC/FTIR-like measurement made since the late 1950s. By a comparison to coincident TCCON (Total Carbon Column Observing Network) measurements, we empirically demonstrate the useful quality of this suggested NDACC XCO2 product (empirically obtained scatter between TCCON and NDACC is about 4‰ for daily mean as well as monthly mean comparisons, and the bias is 25 ‰). Our XCO2 model is a simple regression model fitted to CarbonTracker results and the Mauna Loa CO2 in situ records. A comparison to TCCON data suggests an uncertainty of the model for monthly mean data of below 3 ‰. We apply the method to the NDACC/FTIR spectra that are used within the project MUSICA (multi-platform remote sensing of isotopologues for investigating the cycle of atmospheric water) and demonstrate that there is a good consistency for these globally representative set of spectra measured since 1996: the scatter between the modelled and measured XCO2 on a yearly time scale is only 3 ‰. [less ▲]

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See detailLong-term evolution and seasonal modulation of methanol above Jungfraujoch (46.5°N, 8.0°E): Optimisation of the retrieval strategy, comparison with model and independant observations
Bader, Whitney ULg; Stavrakou, T; Muller, J-F et al

in Atmospheric Measurement Techniques (2014), 7

Methanol (CH3OH) is the second most abundant organic compound in the Earth's atmosphere after methane. In this work, we present the first long-term time series of methanol total, lower tropospheric and ... [more ▼]

Methanol (CH3OH) is the second most abundant organic compound in the Earth's atmosphere after methane. In this work, we present the first long-term time series of methanol total, lower tropospheric and upper tropospheric-lower stratospheric partial columns derived from the analysis of high resolution Fourier transform infrared solar spectra recorded at the Jungfraujoch station (46.5° N, 3580 m a.s.l.). The retrieval of methanol is very challenging due to strong absorptions of ozone in the region of the selected υ8 band of CH3OH. Two wide spectral intervals have been defined and adjusted in order to maximize the information content. Methanol does not exhibit a significant trend over the 1995–2012 time period, but a strong seasonal modulation characterized by maximum values and variability in June–July, minimum columns in winter and a peak-to-peak amplitude of 130%. In situ measurements performed at the Jungfraujoch and ACE-FTS occultations give similar results for the methanol seasonal variation. The total and lower tropospheric columns are also compared with IMAGESv2 model simulations. There is no systematic bias between the observations and IMAGESv2 but the model underestimates the peak-to-peak amplitude of the seasonal modulations. [less ▲]

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See detailRetrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations
Franco, Bruno ULg; Hendrick, François; Van Roozendael, Michel et al

Conference (2014, November 07)

As a ubiquitous product of the oxidation of many Volatile Organic Compounds (VOCs), formaldehyde (HCHO) plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation ... [more ▼]

As a ubiquitous product of the oxidation of many Volatile Organic Compounds (VOCs), formaldehyde (HCHO) plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation pathways leading to the formation of tropospheric ozone and secondary organic aerosols. We have successfully retrieved HCHO columns from ground-based Fourier Transform Infrared (FTIR) solar spectra and UV-Visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) scans recorded during the July 2010 – December 2012 time period at the Jungfraujoch station (Swiss Alps, 46.5 °N, 8.0 °E, 3580 m a.s.l.). Characterization of the retrieved products has revealed different vertical sensitivity between both remote sensing techniques. Furthermore, HCHO amounts simulated by two state-of-the-art Chemical Transport Models (CTMs), GEOS-Chem and IMAGESv2, have been compared to FTIR total columns and MAX-DOAS 3.6 – 8 km partial columns, accounting for the respective vertical resolution of each ground-based instrument. Using the CTMs outputs as intermediate, FTIR and MAX-DOAS retrievals have shown consistent seasonal modulations of HCHO throughout the investigated period, characterized by summertime maximum and wintertime minimum. Such comparisons have also highlighted that FTIR and MAX-DOAS provide complementary products for HCHO above the Jungfraujoch station. [less ▲]

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See detailTrend evolution of Carbonyl Sulfide above Jungfraujoch
Lejeune, Bernard ULg

Conference (2014, May 08)

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See detailLong-term evolution and seasonal modulation of methanol above Jungfraujoch (46.5°N, 8.0°E): Optimisation of the retrieval strategy, comparison with model and independant observations
Bader, Whitney ULg; Stavrakou, J; Muller, J-F et al

Poster (2014, May)

Methanol (CH3OH) is the second most abundant organic compound in the Earth’s atmosphere after methane. In this work, we present the first long-term time series of methanol total, lower tropospheric and ... [more ▼]

Methanol (CH3OH) is the second most abundant organic compound in the Earth’s atmosphere after methane. In this work, we present the first long-term time series of methanol total, lower tropospheric and upper tropospheric-lower stratospheric partial columns derived from the analysis of high resolution Fourier transform infrared solar spectra recorded at the Jungfraujoch station (46.5°N, 3580 m a.s.l.). The retrieval of methanol is very challenging due to strong absorptions of ozone in the region of the selected 8 band of CH3OH. Two wide spectral intervals have been defined and adjusted in order to maximize the information content. Methanol does not exhibit a significant trend over the 1995-2012 time period, but a strong seasonal modulation characterized by maximum values and variability in June-July, minimum columns in winter and a peak-to-peak amplitude of 130 %. In situ measurements performed at the Jungfraujoch and ACE-FTS occultations give similar results for the methanol seasonal variation. The total and lower tropospheric columns are also compared with IMAGESv2 model simulations. There is no systematic bias between the observations and IMAGESv2 but the model underestimates the peak-to-peak amplitude of the seasonal modulations. [less ▲]

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See detailSpectrometric monitoring of atmospheric carbon tetrafluoride (CF4) above the Jungfraujoch station since 1989: evidence of continued increase but at a slowing rate
Mahieu, Emmanuel ULg; Zander, Rodolphe ULg; Toon, G. C. et al

in Atmospheric Measurement Techniques (2014), 7

The long-term evolution of the vertical column abundance of carbon tetrafluoride (CF4) above the high-altitude Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.) has been derived from the ... [more ▼]

The long-term evolution of the vertical column abundance of carbon tetrafluoride (CF4) above the high-altitude Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.) has been derived from the spectrometric analysis of Fourier transform infrared solar spectra recorded at that site between 1989 and 2012. The investigation is based on a multi-microwindow approach, two encompassing pairs of absorption lines belonging to the R-branch of the strong ν3 band of CF4 centered at 1283 cm−1, and two additional ones to optimally account for weak but overlapping HNO3 interferences. The analysis reveals a steady accumulation of the very long-lived CF4 above the Jungfraujoch at mean rates of (1.38 ± 0.11) × 1013 molec cm−2 yr−1 from 1989 to 1997, and (0.98 ± 0.02) × 1013 molec cm−2 yr−1 from 1998 to 2012, which correspond to linear growth rates of 1.71 ± 0.14 and 1.04 ± 0.02% yr−1 respectively referenced to 1989 and 1998. Related global CF4 anthropogenic emissions required to sustain these mean increases correspond to 15.8 ± 1.3 and 11.1 ± 0.2 Gg yr−1 over the above specified time intervals. Findings reported here are compared and discussed with respect to relevant northern mid-latitude results obtained remotely from space and balloons as well as in situ at the ground, including new gas chromatography mass spectrometry measurements performed at the Jungfraujoch since 2010. [less ▲]

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See detailPas d'image fiable de notre atmosphère sans mesures depuis le sol !
De Mazière, M; De Backer, H; Mahieu, Emmanuel ULg et al

Article for general public (2014)

Nous sommes actuellement confrontés à une atmosphère en évolution : les concentrations de ce qu’on appelle les gaz à effet de serre augmentent, la quantité d’ozone stratosphérique diminue, en particulier ... [more ▼]

Nous sommes actuellement confrontés à une atmosphère en évolution : les concentrations de ce qu’on appelle les gaz à effet de serre augmentent, la quantité d’ozone stratosphérique diminue, en particulier au-dessus de l’Antarctique où elle forme chaque année un ‘trou’ dans la couche d’ozone, et l’air n’est pas tous les jours très sain... Comment pouvons-nous détecter et surveiller ces changements pour, si nécessaire, prendre des mesures pour tenter de les contrecarrer ? [less ▲]

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See detailOverview of the geophysical data derived from long-term FTIR monitoring activities at the Jungfraujoch NDACC site (46.5ºN) and the PYGCHEM project
Mahieu, Emmanuel ULg; Bovy, Benoît ULg; Bader, Whitney ULg et al

Poster (2013, May 07)

We present an overview of the geophysical data deduced from long-term monitoring activities conducted at the Jungfraujoch station by the University of Liège. Typical results and trend investigations are ... [more ▼]

We present an overview of the geophysical data deduced from long-term monitoring activities conducted at the Jungfraujoch station by the University of Liège. Typical results and trend investigations are presented for hydrogen chloride (HCl) and carbonyl sulfide (OCS). We further display and briefly describe time series for new target gases, namely methanol (CH3OH) and HCFC-142b. We also show some preliminary results for ammonia (NH3) and peroxyacetyl nitrate (PAN). Finally, we present the PyGChem project, a Python interface to the GEOS-Chem model currently under development at ULg. [less ▲]

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See detailEvolution of methanol (CH3OH) above the Jungfraujoch station (46.5°N) : Variability, seasonal modulation and long-term trend.
Bader, Whitney ULg; Mahieu, Emmanuel ULg; Lejeune, Bernard ULg et al

Poster (2013, April 09)

Methanol (CH3OH) is the second most abundant organic compound in the Earth’s atmosphere with concentrations close to a few ppbv, after methane, despite a short lifetime of a few days (Jacob et al., 2005 ... [more ▼]

Methanol (CH3OH) is the second most abundant organic compound in the Earth’s atmosphere with concentrations close to a few ppbv, after methane, despite a short lifetime of a few days (Jacob et al., 2005). Natural sources of CH3OH include plant growth, oceans, decomposition of plant matter, oxidation of methane and other VOCs,. . . while anthropogenic sources are from vehicles, industry,. . . biomass burning completes the emission budget. The main sink is the oxidation by hydroxyl radical, leading to the formation of carbon monoxide (CO) and formaldehyde (H2CO). The retrieval of methanol is very challenging due to the presence of strong absorption of ozone and its isotopologues in addition to water vapour and carbon dioxide in the region of the selected strong nu8 band of CH3OH. First retrievals from satellite observations using the Atmospheric Chemistry Experiment infrared Fourier Transform Spectrometer (ACE-FTS) on board the SCISAT satellite have been performed by Dufour et al. (2007 and references therein) using a spectral interval going from 995.5 to 1008.3 cm-1. In 2009, first retrievals from a ground-based FTS, using spectra recorded at Kitt Peak (31.9°N) and a window going from 992 to 999 cm-1 have been reported by Rinsland et al. (2009), followed by Vigouroux et al. (2012 and references therein) who used yet another spectral interval going from 1029 to 1037cm-1. From those former retrieval strategies and also considering the Mahieu et al. (2012) contribution, we redefined our spectral intervals to maximize the information content. Indeed, our first window, starting from 992 to 1008.3 cm-1, is issued from the merge of Rinsland et al. and Dufour et al. windows while our second, going from 1029 to 1037 cm-1, is the one used by Vigouroux et al.With this new combination of windows, we were able to enlarge the range of zenith angles providing robust results while maintaining good correlation between our two windows; this also resulted in an improvement of the fitting residuals and of the information content. We used the 2008 HITRAN compilation (Rothman et al., 2009) for spectroscopic parameters. However, systematic residuals still remain in the 1033 cm-1 region which are attributed to unsatisfactory line parameters for methanol. New cross sections recorded at the Molecular Spectroscopy Facility of the Rutherford Appleton Laboratory (Harrison et al. 2012) and calibrated in intensity by using the reference spectra from the Pacific Northwest National Laboratory (PNNL) IR database will be tested as soon as converted into pseudolines. In this work, we will present the first long-term time series of methanol total columns, resulting from the implementation of our new retrieval strategy. All retrievals have been performed with the SFIT2 algorithm (v 3.91) (Rinsland et al., 1998) using a series of about 7 000 spectra recorded between 1995 and 2012, with zenith angles between 60 and 85°. These solar absorption observations have been recorded with a high-resolution FTIR Bruker 120HR instrument, at the high altitude station of the Jungfraujoch (46.5°N, 8°E, 3580 m asl), within the framework of the Network for the Detection of Atmospheric Composition Change (NDACC, visit http://www.ndacc.org). [less ▲]

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See detailFirst retrievals of HCFC-142b from ground-based high resolution FTIR solar observations: application to high altitude Jungfraujoch spectra
Mahieu, Emmanuel ULg; O'Doherty, Simon; Reimann, Stefan et al

in Geophysical Research Abstracts (2013), 15

Hydrofluorocarbons (HCFCs) are the first substitutes to the long-lived ozone depleting halocarbons, in particular the chlorofluorocarbons (CFCs). Given the complete ban of the CFCs by the Montreal ... [more ▼]

Hydrofluorocarbons (HCFCs) are the first substitutes to the long-lived ozone depleting halocarbons, in particular the chlorofluorocarbons (CFCs). Given the complete ban of the CFCs by the Montreal Protocol, its Amendments and Adjustments, HCFCs are on the rise, with current rates of increase substantially larger than at the beginning of the 21st century. HCFC-142b (CH3CClF2) is presently the second most abundant HCFC, after HCFC-22 (CHClF2). It is used in a wide range of applications, including as a blowing foam agent, in refrigeration and air-conditioning. Its concentration will soon reach 25 ppt in the northern hemisphere, with mixing ratios increasing at about 1.1 ppt/yr [Montzka et al., 2011]. The HCFC-142b lifetime is estimated at 18 years. With a global warming potential of 2310 on a 100-yr horizon, this species is also a potent greenhouse gas [Forster et al., 2007]. First space-based retrievals of HCFC-142b have been reported by Dufour et al. [2005]. 17 occultations recorded in 2004 by the Canadian ACE-FTS instrument (Atmospheric Chemistry Experiment – Fourier Transform Spectrometer, onboard SCISAT-1) were analyzed, using two microwindows (1132.5–1135.5 and 1191.5–1195.5 cm-1). In 2009, Rinsland et al. determined the HCFC-142b trend near the tropopause, from the analysis of ACE-FTS observations recorded over the 2004–2008 time period. The spectral region used in this study extended from 903 to 905.5 cm-1. In this contribution, we will present the first HCFC-142b measurements from ground-based high-resolution Fourier Transform Infrared (FTIR) solar spectra. We use observations recorded at the high altitude station of the Jungfraujoch (46.5°N, 8°E, 3580 m asl), with a Bruker 120HR instrument, in the framework of the Network for the Detection of Atmospheric Composition Change (NDACC, visit http://www.ndacc.org). The retrieval of HCFC-142b is very challenging, with simulations indicating only weak absorptions, lower than 1% for low sun spectra and current concentrations. Among the four microwindows tested, the region extending from 900 to 906 cm-1 proved to be the most appropriate, with limited interferences, in particular from water vapor. A total column time series spanning the 2004-2012 time period will be presented, analyzed and critically discussed. After conversion of our total columns to concentrations, we will compare our results with in situ measurements performed in the northern hemisphere by the AGAGE network. [less ▲]

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See detailGround-based remote sensing of tropospheric water vapour isotopologues within the project MUSICA
Schneider, M.; Barthlott, S.; Hase, F. et al

in Atmospheric Measurement Techniques (2012), 5(2012), 3007-3027

Within the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water), long-term tropospheric water vapour isotopologue data records are provided for ... [more ▼]

Within the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water), long-term tropospheric water vapour isotopologue data records are provided for ten globally distributed ground-based mid-infrared remote sensing stations of the NDACC (Network for the Detection of Atmospheric Composition Change). We present a new method allowing for an extensive and straightforward characterisation of the complex nature of such isotopologue remote sensing datasets. We demonstrate that the MUSICA humidity profiles are representative for most of the troposphere with a vertical resolution ranging from about 2 km (in the lower troposphere) to 8 km (in the upper troposphere) and with an estimated precision of better than 10%. We find that the sensitivity with respect to the isotopologue composition is limited to the lower and middle troposphere, whereby we estimate a precision of about 30‰ for the ratio between the two isotopologues HD16O and H216O. The measurement noise, the applied atmospheric temperature profiles, the uncertainty in the spectral baseline, and the cross-dependence on humidity are the leading error sources. We introduce an a posteriori correction method of the cross-dependence on humidity, and we recommend applying it to isotopologue ratio remote sensing datasets in general. In addition, we present mid-infrared CO2 retrievals and use them for demonstrating the MUSICA network-wide data consistency. In order to indicate the potential of long-term isotopologue remote sensing data if provided with a well-documented quality, we present a climatology and compare it to simulations of an isotope incorporated AGCM (Atmospheric General Circulation Model). We identify differences in the multi-year mean and seasonal cycles that significantly exceed the estimated errors, thereby indicating deficits in the modeled atmospheric water cycle. [less ▲]

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