Neptune's Atmospheric Structure from the Spitzer Infrared Spectrometer

2021 ◽  
Author(s):  
Naomi Rowe-Gurney ◽  
Leigh Fletcher ◽  
Glenn Orton ◽  
Michael Roman ◽  
James Sinclair ◽  
...  
Keyword(s):  
Thermal Structure ◽  
Optimal Estimation ◽  
Retrieval Algorithm ◽  
Temperature Structure ◽  
Full Spectrum ◽  
Mid Infrared ◽  
Spatially Resolved ◽  
Stratospheric Temperature ◽  
Chemical Models ◽  
Infrared Spectrometer

<p><strong>Introduction:</strong> NASA’s Spitzer Infrared Spectrometer (IRS) acquired mid-infrared (5 - 37 micron) disc-averaged spectra of Neptune in May 2004, November 2004, November 2005, and May 2006. Meadows et al., (2008, doi: 10.1016/j.icarus.2008.05.023) discovered Neptune's complex hydrocarbons methylacetylene and diacetylene and derived their abundances using the May 2004 data. The rest of the Neptune data has yet to be published. The data have all been reduced using the same methodology as Rowe-Gurney et al., (2021, doi: 10.1016/j.icarus.2021.114506) used for Uranus, so that each year can be reliably compared.</p> <p>We detect the same hydrocarbons seen in Meadows et al., (2008). This includes the strongest bands of methane (CH<sub>4</sub>), acetylene (C<sub>2</sub>H<sub>2</sub>) and ethane (C<sub>2</sub>H<sub>6</sub>) as-well-as weaker but still clearly recognisable features of ethylene (C<sub>2</sub>H<sub>4</sub>), carbon dioxide, methyl (CH<sub>3</sub>), methylacetylene (C<sub>3</sub>H<sub>4</sub>) and diacetylene (C<sub>4</sub>H<sub>2</sub>).</p> <p>At Uranus, there was a considerable longitudinal variation in stratospheric emission detected in the Spitzer data for multiple epochs (Rowe-Gurney et al., 2021). A variation is not present at Neptune in 2005 or late 2004, when all the separate longitudes displayed the same brightness temperature. In May 2004 a stratospheric variation is present, although it is tentative due to the deviation only appearing at a single longitude and because there are larger uncertainties on this early dataset. If the variation is real then it could be caused by stratospheric methane injection associated with convective clouds or perturbations to the location of the south polar warm vortex (Orton et al., 2012, doi: 10.1016/j.pss.2011.06.013).</p> <p><strong>Optimal Estimation Retrievals: </strong>The data from 2005 have optimised exposure times, multiple observed longitudes, and therefore the lowest noise. It is this data we are using to derive the vertical structure of the temperature and composition in the stratosphere and upper troposphere (between around 1 nanobar and 2 bars of pressure). We present full optimal estimation inversions (using the NEMESIS retrieval algorithm, Irwin et al., 2008, doi: 10.1016/j.jqsrt.2007.11.006) of the globally averaged November 2005 data with the aim of constraining the temperature profile and the abundances of the stratospheric hydrocarbons. We fit both the low-resolution (R~120) and high-resolution (R~600) module data, testing multiple temperature priors derived from chemical models (Moses et al., 2018, doi: 10.1016/j.icarus.2018.02.004) and observations from AKARI (Fletcher et al., 2010, doi: 10.1051/0004-6361/200913358). Initial findings show that we are sensitive to stratospheric D/H ratio (derived from the relative abundances of CH<sub>4</sub> and CH<sub>3</sub>D) and therefore we will attempt to constrain this value by finding the best fit for our model.</p> <p><strong>Conclusion:</strong> Full spectrum mid-infrared data from Neptune in 2005 taken by the Spitzer Infrared Spectrometer is to be analysed using optimal estimation retrievals for the first time. The globally-averaged stratospheric temperature structure and the abundances of stratospheric hydrocarbons will be determined along with the ratio of D/H. The disc-averaged thermal and chemical structure from Spitzer will likely be our best characterisation of Neptune’s thermal structure until JWST/MIRI acquired spatially-resolved mid-infrared spectroscopy in 2022.</p>

scholarly journals Longitudinal Variations in the Stratosphere of Uranus from the Spitzer Infrared Spectrometer

2020 ◽  
Author(s):  
Naomi Rowe-Gurney ◽  
Leigh N. Fletcher ◽  
Glenn S. Orton ◽  
Michael T. Roman ◽  
Amy Mainzer ◽  
...  
Keyword(s):  
Temperature Change ◽  
Spatial Resolution ◽  
Optimal Estimation ◽  
Eddy Diffusion ◽  
Retrieval Algorithm ◽  
Temperature Structure ◽  
Longitudinal Variation ◽  
Low Resolution ◽  
Mid Infrared ◽  
Infrared Spectrometer

<p><strong>Introduction:</strong> NASA’s Spitzer Infrared Spectrometer (IRS) acquired mid-infrared (5-37 μm) disc-averaged spectra of Uranus very near its equinox over 21.7 hours on 16th to 17th of December 2007. A global-mean spectrum was constructed from observations of multiple longitudes, spaced equally around the planet, and have provided the opportunity for the most comprehensive globally averaged characterisation of Uranus’ temperature and composition ever obtained (Orton et al., 2014 a, b). In this work, we analyse the disc-averaged spectra at four separate longitudes to shed light on the discovery of longitudinal variability occurring in Uranus’ stratosphere during the 2007 equinox.</p> <p>The composition and temperature structure of Uranus’ stratosphere is dominated by methane photolysis in the upper stratosphere (Moses et al., 2018). The complex hydrocarbons produced in these solar-driven reactions are the main trace gases present in the stratosphere and upper troposphere. These species are observable at mid-infrared wavelengths sensitive to altitudes between around one nanobar and two bars of pressure (Orton et al., 2014a).</p> <p>Due to Uranus’ extremely high obliquity we can only clearly observe its longitudinal variation in disc-averaged observations close to its equinox. The northern spring equinox occurred in December 2007 with the aforementioned Spitzer observations occurring just 10 days after. The Spitzer data have been re-analysed using the most up to date pipeline available from NASA’s Spitzer Science Centre, resulting in minor changes over the previous reduction.</p> <p><strong>Longitudinal Variation:</strong> We assess the variations in discrete channels sensitive to different emission features. The radiances inside each interval are averaged and compared to the mean of all four longitudes. Each instrument module is exposed at a different time causing a spread of data points across the multiple longitudes displayed in Figure 1.</p> <p>We detect a variability of up to 15% at stratospheric altitudes sensitive to the hydrocarbon species at around the 0.1-mbar pressure level. The tropospheric hydrogen-helium continuum and the monodeuterated methane that also arises from these deeper levels, both exhibit a negligible variation smaller than 2%, constraining the phenomenon to the stratosphere. Observations from Keck II NIRCII in December 2007 (Sromovsky et al., 2009; de Pater et al., 2011) and VLT/VISIR in 2009 (Roman et al. 2020) suggest possible links to these variations in the form of discrete meteorological features. In particular, Roman et al. (2020) identified discrete patches of brightness in 13-μm (acetylene) emission within a broad stratospheric band at mid-latitudes, which could be related to the variability observed by Spitzer.</p> <p><strong>Optimal Estimation Retrievals:</strong> Building on the forward-modelling analysis of the global average study, we present full optimal estimation inversions (using the NEMESIS retrieval algorithm, Irwin et al., 2008) of the low-resolution spectra at each longitude to distinguish between thermal and compositional variability. The model suggests that variations can be explained solely by changes in stratospheric temperatures. A temperature change of less than 2 K is needed to model the observed variation. This is compounded by results from high-resolution forward models (primarily sounding the ethane and acetylene emission) constructed using the parameters retrieved from the low-resolution spectra.</p> <p>The data were best reproduced by models with atmospheric mixing via eddy diffusion that was weaker than that assumed by Orton et al. but still within the confines of a realistic fit according to their model. An eddy diffusion coefficient value of 1020 cm<sup>2</sup>sec<sup>-1</sup> and a tropopause methane mole fraction of 8.0x10<sup>-5</sup> provides the best fit to the temperature structure and the methane vertical profile whilst also maintaining the closest chi-squared value for the spectral fit (Moses et al., 2018).</p> <p><strong>Conclusion:</strong> The longitudinal variation detected at Uranus during the 2007 equinox is an observed physical change in the stratosphere of the planet, most likely a temperature change associated with the band of bright stratospheric emission observed in ground-based images. The Spitzer IRS data can provide much detail but without accompanying spatial resolution it is impossible to come to a definitive conclusion as to the origins of the changes.</p> <p>The James Webb Space Telescope, when it launches in 2021, will provide much improved spectral and spatial resolution needed in the mid-infrared band to provide answers to the causes of the observed variation.</p>

scholarly journals Validation of ACE and OSIRIS ozone and NO<sub>2</sub> measurements using ground-based instruments at 80° N

2012 ◽  
Vol 5 (5) ◽  
pp. 927-953 ◽  
Author(s):  
C. Adams ◽  
K. Strong ◽  
R. L. Batchelor ◽  
P. F. Bernath ◽  
S. Brohede ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Polar Vortex ◽  
Optimal Estimation ◽  
Relative Difference ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Photochemical Model ◽  
Stratospheric Temperature ◽  
Infrared Spectrometer ◽  
Relative Differences

Abstract. The Optical Spectrograph and Infra-Red Imager System (OSIRIS) and the Atmospheric Chemistry Experiment (ACE) have been taking measurements from space since 2001 and 2003, respectively. This paper presents intercomparisons between ozone and NO2 measured by the ACE and OSIRIS satellite instruments and by ground-based instruments at the Polar Environment Atmospheric Research Laboratory (PEARL), which is located at Eureka, Canada (80° N, 86° W) and is operated by the Canadian Network for the Detection of Atmospheric Change (CANDAC). The ground-based instruments included in this study are four zenith-sky differential optical absorption spectroscopy (DOAS) instruments, one Bruker Fourier transform infrared spectrometer (FTIR) and four Brewer spectrophotometers. Ozone total columns measured by the DOAS instruments were retrieved using new Network for the Detection of Atmospheric Composition Change (NDACC) guidelines and agree to within 3.2%. The DOAS ozone columns agree with the Brewer spectrophotometers with mean relative differences that are smaller than 1.5%. This suggests that for these instruments the new NDACC data guidelines were successful in producing a homogenous and accurate ozone dataset at 80° N. Satellite 14–52 km ozone and 17–40 km NO2 partial columns within 500 km of PEARL were calculated for ACE-FTS Version 2.2 (v2.2) plus updates, ACE-FTS v3.0, ACE-MAESTRO (Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) v1.2 and OSIRIS SaskMART v5.0x ozone and Optimal Estimation v3.0 NO2 data products. The new ACE-FTS v3.0 and the validated ACE-FTS v2.2 partial columns are nearly identical, with mean relative differences of 0.0 ± 0.2% and −0.2 ± 0.1% for v2.2 minus v3.0 ozone and NO2, respectively. Ozone columns were constructed from 14–52 km satellite and 0–14 km ozonesonde partial columns and compared with the ground-based total column measurements. The satellite-plus-sonde measurements agree with the ground-based ozone total columns with mean relative differences of 0.1–7.3%. For NO2, partial columns from 17 km upward were scaled to noon using a photochemical model. Mean relative differences between OSIRIS, ACE-FTS and ground-based NO2 measurements do not exceed 20%. ACE-MAESTRO measures more NO2 than the other instruments, with mean relative differences of 25–52%. Seasonal variation in the differences between NO2 partial columns is observed, suggesting that there are systematic errors in the measurements and/or the photochemical model corrections. For ozone spring-time measurements, additional coincidence criteria based on stratospheric temperature and the location of the polar vortex were found to improve agreement between some of the instruments. For ACE-FTS v2.2 minus Bruker FTIR, the 2007–2009 spring-time mean relative difference improved from −5.0 ± 0.4% to −3.1 ± 0.8% with the dynamical selection criteria. This was the largest improvement, likely because both instruments measure direct sunlight and therefore have well-characterized lines-of-sight compared with scattered sunlight measurements. For NO2, the addition of a ±1° latitude coincidence criterion improved spring-time intercomparison results, likely due to the sharp latitudinal gradient of NO2 during polar sunrise. The differences between satellite and ground-based measurements do not show any obvious trends over the missions, indicating that both the ACE and OSIRIS instruments continue to perform well.

scholarly journals Validation of ACE and OSIRIS ozone and NO<sub>2</sub> measurements using ground-based instruments at 80° N

2012 ◽  
Vol 5 (1) ◽  
pp. 517-588 ◽  
Author(s):  
C. Adams ◽  
K. Strong ◽  
R. L. Batchelor ◽  
P. F. Bernath ◽  
S. Brohede ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Polar Vortex ◽  
Optimal Estimation ◽  
Relative Difference ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Photochemical Model ◽  
Stratospheric Temperature ◽  
Infrared Spectrometer ◽  
Relative Differences

Abstract. The Optical Spectrograph and Infra-Red Imager System (OSIRIS) and the Atmospheric Chemistry Experiment (ACE) have been taking measurements from space since 2001 and 2003, respectively. This paper presents intercomparisons between ozone and NO2 measured by the ACE and OSIRIS satellite instruments and by ground-based instruments at the Polar Environment Atmospheric Research Laboratory (PEARL), which is located at Eureka, Canada (80° N, 86° W) and is operated by the Canadian Network for the Detection of Atmospheric Change (CANDAC). The ground-based instruments included in this study are four zenith-sky differential optical absorption spectroscopy (DOAS) instruments, one Bruker Fourier transform infrared spectrometer (FTIR) and four Brewer spectrophotometers. Ozone total columns measured by the DOAS instruments were retrieved using new Network for the Detection of Atmospheric Composition Change (NDACC) guidelines and agree to within 3.2%. The DOAS ozone columns agree with the Brewer spectrophotometers with mean relative differences that are smaller than 1.5%. This suggests that for these instruments the new NDACC data guidelines were successful in producing a homogenous and accurate ozone dataset at 80° N. Satellite 14–52 km ozone and 17–40 km NO2 partial columns within 500 km of PEARL were calculated for ACE-FTS Version 2.2 (v2.2) plus updates, ACE-FTS v3.0, ACE-MAESTRO (Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) v1.2 and OSIRIS SaskMART v5.0x ozone and Optimal Estimation v3.0 NO2 data products. The new ACE-FTS v3.0 and the validated ACE-FTS v2.2 partial columns are nearly identical, with mean relative differences of 0.0 ± 0.2% for ozone and −0.2 ± 0.1% for v2.2 minus v3.3 NO2. Ozone columns were constructed from 14–52 km satellite and 0–14 km ozonesonde partial columns and compared with the ground-based total column measurements. The satellite-plus-sonde measurements agree with the ground-based ozone total columns with mean relative differences of 0.1–7.3%. For NO2, partial columns from 17 km upward were scaled to noon using a photochemical model. Mean relative differences between OSIRIS, ACE-FTS and ground-based NO2 measurements do not exceed 20%. ACE-MAESTRO measures more NO2 than the other instruments, with mean relative differences of 25–52%. Seasonal variation in the differences between partial columns is observed, suggesting that there are systematic errors in the measurements, the photochemical model corrections, and/or in the coincidence criteria. For ozone spring-time measurements, additional coincidence criteria based on stratospheric temperature and the location of the polar vortex were found to improve agreement between some of the instruments. For ACE-FTS v2.2 minus Bruker FTIR, the 2007–2009 spring-time mean relative difference improved from −5.0 ± 0.4% to −3.1 ± 0.8% with the dynamical selection criteria. This was the largest improvement, likely because both instruments measure direct sunlight and therefore have well-characterized lines-of-sight compared with scattered sunlight measurements. For NO2, the addition of a ±1° latitude coincidence criterion improved spring-time intercomparison results, likely due to the sharp latitudinal gradient of NO2 during polar sunrise. The differences between satellite and ground-based measurements do not show any obvious trends over the missions, indicating that both the ACE and OSIRIS instruments continue to perform well.

scholarly journals First detections of H13CO+ and HC15N in the disk around HD 97048

2019 ◽  
Vol 629 ◽  
pp. A75 ◽  
Author(s):  
Alice S. Booth ◽  
Catherine Walsh ◽  
John D. Ilee
Keyword(s):  
Dust Emission ◽  
Line Emission ◽  
Abundance Ratio ◽  
Protoplanetary Disk ◽  
Temperature Structure ◽  
Exchange Reactions ◽  
Gas Kinematics ◽  
Spatially Resolved ◽  
Chemical Models ◽  
Disk Structure

Observations of different molecular lines in protoplanetary disks provide valuable information on the gas kinematics, as well as constraints on the radial density and temperature structure of the gas. With ALMA we have detected H13CO+ (J = 4–3) and HC15N (J = 4–3) in the HD 97048 protoplanetary disk for the first time. We compare these new detections to the ringed continuum mm-dust emission and the spatially resolved CO (J = 3–2) and HCO+ (J = 4–3) emission. The radial distributions of the H13CO+ and HC15N emission show hints of ringed sub-structure whereas, the optically thick tracers, CO and HCO+, do not. We calculate the HCO+/H13CO+ intensity ratio across the disk and find that it is radially constant (within our uncertainties). We use a physio-chemical parametric disk structure of the HD 97048 disk with an analytical prescription for the HCO+ abundance distribution to generate synthetic observations of the HCO+ and H13CO+ disk emission assuming LTE. The best by-eye fit models require radial variations in the HCO+/H13CO+ abundance ratio and an overall enhancement in H13CO+ relative to HCO+. This highlights the need to consider isotope selective chemistry and in particular low temperature carbon isotope exchange reactions. This also points to the presence of a reservoir of cold molecular gas in the outer disk (T ≲ 10 K, R ≳ 200 au). Chemical models are required to confirm that isotope-selective chemistry alone can explain the observations presented here. With these data, we cannot rule out that the known dust substructure in the HD 97048 disk is responsible for the observed trends in molecular line emission, and higher spatial resolution observations are required to fully explore the potential of optically thin tracers to probe planet-carved dust gaps. We also report non-detections of H13CO+ and HC15N in the HD 100546 protoplanetary disk.

scholarly journals The Flying Saucer: Tomography of the thermal and density gas structure of an edge-on protoplanetary disk

2017 ◽  
Vol 607 ◽  
pp. A130 ◽  
Author(s):  
A. Dutrey ◽  
S. Guilloteau ◽  
V. Piétu ◽  
E. Chapillon ◽  
V. Wakelam ◽  
...  
Keyword(s):  
Thermal Structure ◽  
Direct Determination ◽  
Molecular Data ◽  
Temperature Structure ◽  
Gas Temperature ◽  
Star Forming ◽  
Star Forming Regions ◽  
Flying Saucer ◽  
Grain Properties

Context. Determining the gas density and temperature structures of protoplanetary disks is a fundamental task in order to constrain planet formation theories. This is a challenging procedure and most determinations are based on model-dependent assumptions. Aims. We attempt a direct determination of the radial and vertical temperature structure of the Flying Saucer disk, thanks to its favorable inclination of 90 degrees. Methods. We present a method based on the tomographic study of an edge-on disk. Using ALMA, we observe at 0.5″ resolution the Flying Saucer in CO J = 2–1 and CS J = 5–4. This edge-on disk appears in silhouette against the CO J = 2–1 emission from background molecular clouds in ρ Oph. The combination of velocity gradients due to the Keplerian rotation of the disk and intensity variations in the CO background as a function of velocity provide a direct measure of the gas temperature as a function of radius and height above the disk mid-plane. Results. The overall thermal structure is consistent with model predictions, with a cold (<12−15 K) CO-depleted mid-plane and a warmer disk atmosphere. However, we find evidence for CO gas along the mid-plane beyond a radius of about 200 au, coincident with a change of grain properties. Such behavior is expected in the case of efficient rise of UV penetration re-heating the disk and thus allowing CO thermal desorption or favoring direct CO photo-desorption. CO is also detected at up to 3–4 scale heights, while CS is confined to around 1 scale height above the mid-plane. The limits of the method due to finite spatial and spectral resolutions are also discussed. Conclusions. This method appears to be a very promising way to determine the gas structure of planet-forming disks, provided that the molecular data have an angular resolution which is high enough, on the order of 0.3−0.1″ at the distance of the nearest star-forming regions.

scholarly journals Spatially Resolved Mid‐Infrared Spectroscopy of NGC 1068: The Nature and Distribution of the Nuclear Material

2006 ◽  
Vol 640 (2) ◽  
pp. 612-624 ◽  
Author(s):  
R. E. Mason ◽  
T. R. Geballe ◽  
C. Packham ◽  
N. A. Levenson ◽  
M. Elitzur ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Nuclear Material ◽  
Mid Infrared ◽  
Mid Infrared Spectroscopy ◽  
Spatially Resolved ◽  
Ngc 1068

Low-Frequency Photoacoustic Spectroscopy of Solids

1988 ◽  
Vol 42 (2) ◽  
pp. 289-292 ◽  
Author(s):  
J. C. Donini ◽  
K. H. Michaelian
Keyword(s):  
Fourier Transform ◽  
Carbon Black ◽  
Low Frequency ◽  
Far Infrared ◽  
Research Quality ◽  
Signal To Noise ◽  
Single Spectrum ◽  
Mid Infrared ◽  
Infrared Spectrometer ◽  
Computational Procedures

Research-quality far-infrared photoacoustic (PA) spectra are obtainable with a Fourier transform infrared spectrometer, the only changes with respect to conventional mid-infrared PA spectroscopy being the use of (1) a caesium iodide or polyethylene window on the PA cell, and (2) a mylar beamsplitter. Far-infrared PA spectra of several solids (bentonite, Fe+3-bentonite, and asbestos), in addition to the PA reference carbon black, have been recorded in this way. In order to improve signal-to-noise ratios in one of the spectra, we recorded ten interferograms under identical conditions; it was found that the average of the ten individually calculated spectra displays less noise and fewer spurious features than the spectrum obtained by first averaging the interferograms and then calculating a single spectrum. The results of this investigation demonstrate the feasibility of far-infrared PA spectroscopy, and illustrate that both experimental and computational procedures should be optimized in order to obtain the most satisfactory spectra.

Validation of TROPOMI nadir ozone profile retrievals: Methodology and first results

2021 ◽  
Author(s):  
Arno Keppens ◽  
Jean-Christopher Lambert ◽  
Daan Hubert ◽  
Steven Compernolle ◽  
Tijl Verhoelst ◽  
...  
Keyword(s):  
Near Infrared ◽  
Stratospheric Ozone ◽  
Estimation Method ◽  
Optimal Estimation ◽  
Data Retrieval ◽  
Atmospheric Composition ◽  
Retrieval Algorithm ◽  
Validation Data ◽  
Ozone Profile ◽  
Early Afternoon

&lt;p&gt;Part of the space segment of EU&amp;#8217;s Copernicus Earth Observation programme, the Sentinel-5 Precursor (S5P) mission is dedicated to global and European atmospheric composition measurements of air quality, climate and the stratospheric ozone layer. On board of the S5P early afternoon polar satellite, the imaging spectrometer TROPOMI (TROPOspheric Monitoring Instrument) performs nadir measurements of the Earth radiance within the UV-visible and near-infrared spectral ranges, from which atmospheric ozone profile data are retrieved. Developed at the Royal Netherlands Meteorological Institute (KNMI) and based on the optimal estimation method, TROPOMI&amp;#8217;s operational ozone profile retrieval algorithm has recently been upgraded. With respect to early retrieval attempts, accuracy is expected to have improved significantly, also thanks to recent updates of the TROPOMI Level-1b data product. This work reports on the initial validation of the improved TROPOMI height-resolved ozone data in the troposphere and stratosphere, as collected both from the operational S5P Mission Performance Centre/Validation Data Analysis Facility (MPC/VDAF) and from the S5PVT scientific project CHEOPS-5p. Based on the same validation best practices as developed for and applied to heritage sensors like GOME-2, OMI and IASI (Keppens et al., 2015, 2018), the validation methodology relies on the analysis of data retrieval diagnostics &amp;#8211; like the averaging kernels&amp;#8217; information content &amp;#8211; and on comparisons of TROPOMI data with reference ozone profile measurements. The latter are acquired by ozonesonde, stratospheric lidar, and tropospheric lidar stations performing network operation in the context of WMO's Global Atmosphere Watch and its contributing networks NDACC and SHADOZ. The dependence of TROPOMI&amp;#8217;s ozone profile uncertainty on several influence quantities like cloud fraction and measurement parameters like sun and scan angles is examined and discussed. This work concludes with a set of quality indicators, enabling users to verify the fitness-for-purpose of the S5P data.&lt;/p&gt;

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