A quantitative analysis of the reactions involved in stratospheric ozone depletion in the polar vortex core

Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

doi:10.5194/acp-17-10535-2017

Cited by 24 publications

(83 citation statements)

References 56 publications

(155 reference statements)

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“…Having ruled out technical changes to the simulation and to the instrumental sides during this time, it seems as if we can observe a model bias that is known from satellite comparisons at higher altitudes in the dark polar vortices, a problem that is observed by other models as well (Wohltmann et al, 2017;Grooß et al, 2018). Our intercomparison of model and in situ data supports the rationale that chemistry-climate models struggle in reproducing the observed chlorine partitioning in the dark winter months, where some unknown process for HCl removal is lacking.…”

Section: Comparison Of Measured and Clams-modelled Datamentioning

confidence: 92%

“…from the Microwave Limb Sounder (MLS) or the Atmospheric Chemistry Instrument-Fourier Transform Spectrometer (ACE-FTS), do not achieve the high vertical resolution necessary to resolve strong concentration gradients near the tropopause (e.g. Livesey et al, 2017;Mahieu et al, 2008;Wolff et al, 2008). On the other hand, there have been numerous airborne activities in the Arctic LMS, but only a few airborne (Bonne et al, 2000;Wilmouth et al, 2006) or balloon-borne (e.g.…”

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confidence: 99%

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Chlorine partitioning in the lowermost Arctic vortex during the cold winter 2015/2016

Marsing

Jurkat‐Witschas

Grooß³

et al. 2019

Atmos. Chem. Phys.

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Activated chlorine compounds in the polar winter stratosphere drive catalytic cycles that deplete ozone and methane, whose abundances are highly relevant to the evolution of global climate. The present work introduces a novel dataset of in situ measurements of relevant chlorine species in the lowermost Arctic stratosphere from the aircraft mission POLSTRACC-GW-LCYCLE-SALSA during winter 2015/2016. The major stages of chemical evolution of the lower polar vortex are presented in a consistent series of high-resolution mass spectrometric observations of HCl and ClONO 2 . Simultaneous measurements of CFC-12 are used to derive total inorganic chlorine (Cl y ) and active chlorine (ClO x ). The new data highlight an altitude dependence of the pathway for chlorine deactivation in the lowermost vortex with HCl dominating below the 380 K isentropic surface and ClONO 2 prevailing above. Further, we show that the Chemical Lagrangian Model of the Stratosphere (CLaMS) is generally able to reproduce the chemical evolution of the lower polar vortex chlorine budget, except for a bias in HCl concentrations. The model is used to relate local measurements to the vortex-wide evolution. The results are aimed at fostering our understanding of the climate impact of chlorine chemistry, providing new observational data to complement satellite data and assess model performance in the climatesensitive upper troposphere and lower stratosphere region.

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Section: Comparison Of Measured and Clams-modelled Datamentioning

confidence: 92%

mentioning

confidence: 99%

Chlorine partitioning in the lowermost Arctic vortex during the cold winter 2015/2016

Marsing

Jurkat‐Witschas

Grooß³

et al. 2019

Atmos. Chem. Phys.

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“…The microphysics of Polar Stratospheric Clouds (PSCs) and their impact on the chemistry is taken into account by a simple parameterization as described in Huijnen et al (2016) but with several updates. In its original implementation, the CTM overestimated the loss of HCl by heterogeneous chemistry (in contrast to other models which underestimate the loss of HCl, see Wohltmann et al, 2017;Grooß et al, 2018). Preliminary experiments prior to BRAM2 showed that data assimilation was not able to correct for this bias (not shown).…”

Section: Bascoementioning

confidence: 99%

“…The species shown in Fig. 7 (Wohltmann et al, 2017;Grooß et al, 2018). Note that the BASCOE CTM is based on a relatively simple PSC parameterization and that its parameters have been tuned to improve the model representation (see Sect.…”

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confidence: 99%

Technical note: Reanalysis of Aura MLS Chemical Observations

Errera¹,

Chabrillat²,

Christophe³

et al. 2019

Preprint

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Abstract. This paper presents a reanalysis of the atmospheric chemical composition from the upper troposphere to the lower mesosphere from August 2004 to December 2017. This reanalysis is produced by the Belgian Assimilation System for Chemical ObsErvations (BASCOE) constrained by the chemical observations from the Microwave Limb Sounder (MLS) onboard the Aura satellite. BASCOE is based on the Ensemble Kalman Filter (EnKF) method and includes a chemical transport model driven by the winds and temperature from the ERA-Interim meteorological reanalysis. The model resolution is 3.75&#176; in longitude, 2.5&#176; in latitude and 37 vertical levels from the surface to 0.1&#8201;hPa with 25 levels above 100&#8201;hPa. The outputs are provided every 6 hours. This reanalysis is called BRAM2 for BASCOE Reanalysis of Aura MLS, version 2. Vertical profiles of eight species from MLS version 4 are assimilated and are evaluated in this paper: ozone (O3), water vapour (H2O), nitrous oxide (N2O), nitric acid (HNO3), hydrogen chloride (HCl), chlorine oxide (ClO), methyl chloride (CH3Cl) and carbon monoxide (CO). They are evaluated using independent observations from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACEFTS), the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES), N2O observations from another MLS radiometer than the one used to deliver the standard product and ozonesondes. The evaluation is done in four regions of interest where only selected species are evaluated. These regions are (1) the lower stratospheric polar vortex where O3, H2O, N2O, HNO3, HCl and ClO are evaluated, (2) the upper stratospheric lower mesospheric polar vortex where H2O, N2O, HNO3 and CO are evaluated, (3) the tropical tropopause layer (TTL) where O3, H2O, CO and CH3Cl are evaluated and (4) the middle stratosphere where O3, H2O, N2O, HNO3, HCl, ClO and CH3Cl are evaluated. In general BRAM2 reproduces MLS observations within their uncertainties and agrees well with independent observations, with several limitations discussed in this paper (see the summary in Sect. 5.5). In particular, ozone is not assimilated at altitudes above (i.e. pressures lower than) 4&#8201;hPa due to a model bias that cannot be corrected by the assimilation. MLS ozone profiles display unphysical oscillations in the TTL which are corrected by the assimilation, allowing a good agreement with ozonesondes. Moreover, in the upper troposphere, comparison of BRAM2 with MLS and independent observations suggests a positive bias in MLS O3 and a negative bias in MLS H2O. The reanalysis also reveals a drift in MLS N2O against independent observations which highlights the potential use of BRAM2 to estimate biases between instruments. BRAM2 is publicly available and will be extended to assimilate MLS observations post 2017.

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“…However, within the area of the southern polar vortex, severe stratospheric ozone losses have been observed since the late 1970s, especially in September and October (e.g., [3][4][5]). The enhanced depletion has been explained by the chemical reaction between the ozone molecules and man-made chemicals, such as chlorofluorocarbons (CFCs), e.g., [6,7]. The use and manufacture of Along with the above-mentioned global validations, there are much fewer detailed, site-based studies covering the Antarctic continent.…”

Section: Introductionmentioning

confidence: 99%

Intercomparison of Ground- and Satellite-Based Total Ozone Data Products at Marambio Base, Antarctic Peninsula Region

et al. 2019

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This study aims to compare the ground-based Brewer spectrophotometer total ozone column measurements with the Dobson spectrophotometer and various satellite overpass data available at Marambio Base during the period 2011–2013. This station provides a unique opportunity to study ozone variability near the edge of the southern polar vortex; therefore, many institutions, such as the National Meteorological Service of Argentina, the Finnish Meteorological Institute and the Czech Hydrometeorological Institute, have been carrying out various scientific activities there. The intercomparison was performed using total ozone column data sets retrieved from the ground-based instruments and from Ozone Monitoring Instrument (OMI)—Total Ozone Mapping Spectrometer (TOMS), OMI–Differential Optical Absorption Spectroscopy (DOAS), Global Ozone Monitoring Experiment 2 (GOME2), and Scanning Imaging Absorption Spectrophotometer for Atmospheric Cartography (SCIAMACHY) satellite observations. To assess the quality of the selected data products, comparisons with reference to the Brewer spectrophotometer single observations were made. The performance of the satellite observational techniques was assessed against the solar zenith angle and effective temperature, as well as against the actual shape of the vertical ozone profiles, which represent an important input parameter for the satellite ozone retrievals. The ground-based Dobson observations showed the best agreement with the Brewer data set (R2 = 1.00, RMSE = 1.5%); however, significant solar zenith angle (SZA) dependency was found. The satellite overpass data confirmed good agreement with the Brewer observations but were, however, overestimated in all cases except for the OMI(TOMS), when the mean bias differed from −0.7 DU in the case of the OMI(TOMS) to 6.4 DU for the SCIAMACHY. The differences in satellite observational techniques were further evaluated using statistical analyses adapted for depleted and non-depleted conditions over the ozone hole period.

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A quantitative analysis of the reactions involved in stratospheric ozone depletion in the polar vortex core

Cited by 24 publications

References 56 publications

Chlorine partitioning in the lowermost Arctic vortex during the cold winter 2015/2016

Chlorine partitioning in the lowermost Arctic vortex during the cold winter 2015/2016

Technical note: Reanalysis of Aura MLS Chemical Observations

Intercomparison of Ground- and Satellite-Based Total Ozone Data Products at Marambio Base, Antarctic Peninsula Region

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