Chlorine in the stratosphere

Clarmann, T. von

doi:10.1016/s0187-6236(13)71086-5

Cited by 22 publications

(10 citation statements)

References 429 publications

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“…The increase of perchlorate in Antarctic snow since the late 1970s coincides with the timing of significant increases of chlorine in the stratosphere [World Meteorological Organization, 2014]. Anthropogenic emissions of chlorine compounds-including chlorofluorcarbons (CFCs)-during the latter half of the twentieth century [Montzka et al, 1999;Schauffler et al, 2003;Von Clarmann, 2013] has been identified as the key factor in increased levels of chlorine in the stratosphere. The amount of chlorine in the stratosphere may be represented by equivalent effective stratospheric chlorine (EESC)-a parameter based on emission calculations and ozone depletion potentials [Newman et al, 2007].…”

Section: 1002/2016gl070203mentioning

confidence: 99%

Trends of perchlorate in Antarctic snow: Implications for atmospheric production and preservation in snow

Jiang

Cox

Cole‐Dai

et al. 2016

Geophysical Research Letters

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Perchlorate concentration ranges from a few to a few hundred ng kg−1 in surface and shallow‐depth snow at three Antarctic locations (South Pole, Dome A, and central West Antarctica), with significant spatial variations dependent on snow accumulation rate and/or atmospheric production rate. An obvious trend of increasing perchlorate since the 1970s is seen in South Pole snow. The trend is possibly the result of stratospheric chlorine levels elevated by anthropogenic chlorine emissions; this is supported by the timing of a similar trend at Dome A. Alternatively, the trend may stem from postdepositional loss of snowpack perchlorate or a combination of both. The possible impact of stratospheric chlorine is consistent with evidence of perchlorate production in the stratosphere. Additionally, perchlorate concentration appears to be directly affected by the springtime Antarctic ozone hole. Therefore, perchlorate variations in Antarctic snow are likely linked to stratospheric chemistry and ozone over the Antarctic.

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Section: 1002/2016gl070203mentioning

confidence: 99%

Trends of perchlorate in Antarctic snow: Implications for atmospheric production and preservation in snow

Jiang

Cox

Cole‐Dai

et al. 2016

Geophysical Research Letters

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“…Deactivation of active chlorine into ClONO 2 has not been at the observable expense of HCl reformation rate (in both 2002 and 2019). Such fast premature deactivation of active chlorine into ClONO 2 early in the Antarctic season is more akin to that seen in the warmer, and less denitrified, Arctic spring stratosphere (Douglass et al, 1995;Santee et al, 1995;Rex et al, 1997;Von Clarmann, 2013). As we will see in section 5.4 the rapid rise in ClONO 2 early in the springtime correlates with an equally fast deactivation of ClO and synchronized with an increase in temperature and NO 2 .…”

Section: Hydrogen Chloride (Hcl) and Chlorine Nitrate (Clono 2 )mentioning

confidence: 67%

Evolution of observed ozone, trace gases, and meteorological variables over Arrival Heights, Antarctica (77.8°S, 166.7°E) during the 2019 Antarctic stratospheric sudden warming

Smale

Strahan

Querel

et al. 2021

Tellus B: Chemical and Physical Meteorology

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We use ground-based spectroscopic remote sensing measurements of the stratospheric trace gases O 3 , HCl, ClO, BrO, HNO 3 , NO 2 , OClO, ClONO 2 , N 2 O and HF, along with radiosonde profiles of temperature to track the springtime development of the 2019 ozone hole over Arrival Heights (77.8 S, 166.7 E, AHTS), Antarctica, during, and after, the 2019 stratospheric sudden warming (SSW) event. Both measurements and model simulations show that the 2019 SSW caused an extraordinarily warm stratosphere within the polar vortex, resulting in record low ozone depletion over AHTS. We also contrast the evolution of the 2019 ozone hole to that in 2002, which also had a major springtime SSW event.The SSW event started around 28 th August. By $17 th September, stratospheric temperatures inside the polar vortex over AHTS were $45 K higher than the climatological average. The SSW did not cause an en masse displacement of mid-latitude air over AHTS as in the 2002 SSW event. However, the increased temperatures did cause an unusually early reduction in polar stratospheric clouds, halting the denitrification early and leading to increased gas-phase HNO 3 and record high levels of NO 2 ('renoxification'). This caused the earliest observed deactivation of chlorine, returning all active chlorine into the chlorine reservoir species, HCl and ClONO 2 . The deactivation rate into HCl remained relatively unaffected by the SSW, whilst there was a dramatic increase in ClONO 2 formation. This chlorine deactivation pathway via ClONO 2 is typical of the Arctic and atypical for the Antarctic.At AHTS, record high levels of springtime ozone were observed. The measured ozone total column did not drop below 220 DU. Record high stratospheric temperatures persisted until 7 th October over AHTS. By 22 nd October, AHTS was not beneath the polar vortex. The polar vortex break-up date on 9 th November was one of the earliest observed.

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“…Panel a) illustrates the composite mean ClO August through late September). This is followed by a large reduction in ClO mixing ratio, due to deactivation of chlorine with the reformation of its reservoirs (von Clarmann, 2013). Note that values below zero are a result of the known negative bias in MLS ClO.…”

Section: Mls Clo Observationsmentioning

confidence: 98%

Observational evidence of EPP–NO<sub><i>x</i></sub> interaction with chlorine curbing Antarctic ozone loss

Gordon

Seppälä

Funke

et al. 2020

Preprint

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Abstract. We investigate the impact of the so-called energetic particle precipitation (EPP) indirect effect on lower stratospheric ozone, ClO and ClONO2 in the Antarctic springtime. We use observations from Microwave Limb Sounder (MLS) and Ozone Monitoring Instrument (OMI) on Aura, Atmospheric Chemistry Experiment – Fourier Transform Spectrometer (ACE-FTS) on SciSat, and Michelson Interferometer for Passive Atmospheric Sound (MIPAS) on Envisat, covering the overall period of 2005–2017. Using the Ap index to proxy EPP, we find consistent ozone increases with elevated EPP during years with easterly phase of the quasi biennial oscillation (QBO) in both OMI and MLS observations. While these increases are opposite to what has been previously reported at higher altitudes, the pattern in the MLS O3 follows the typical descent patterns of EPP–NOx. The ozone enhancements are also present in the OMI total O3 column observations. Analogous to the descent patterns found in O3, we also found consistent decreases in springtime MLS ClO following winters of elevated EPP. To verify if this is due to a previously proposed mechanism of conversion of ClO to the reservoir species ClONO2 in reaction with NO2, we used ClONO2 observations from ACE-FTS and MIPAS. As ClO and NO2 are both catalysts in ozone destruction, the conversion into ClONO2 would result in ozone increase. We find a positive correlation between EPP and ClONO2 in the upper stratosphere in the early spring, and the lower stratosphere in late spring, providing the first observational evidence supporting the previously proposed mechanism relating to EPP–NOx modulating Clx driven ozone loss. Our findings suggest that EPP has played an important role in modulating ozone depletion in the last 15 years. As chlorine loading in the polar stratosphere continues to decrease in the future, this buffering mechanism will become less effective and catalytic ozone destruction by EPP–NOx will likely become a major contributor to Antarctic ozone loss.

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Chlorine in the stratosphere

Cited by 22 publications

References 429 publications

Trends of perchlorate in Antarctic snow: Implications for atmospheric production and preservation in snow

Trends of perchlorate in Antarctic snow: Implications for atmospheric production and preservation in snow

Evolution of observed ozone, trace gases, and meteorological variables over Arrival Heights, Antarctica (77.8°S, 166.7°E) during the 2019 Antarctic stratospheric sudden warming

Observational evidence of EPP–NO<sub><i>x</i></sub> interaction with chlorine curbing Antarctic ozone loss

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Chlorine in the stratosphere

Cited by 22 publications

References 429 publications

Trends of perchlorate in Antarctic snow: Implications for atmospheric production and preservation in snow

Trends of perchlorate in Antarctic snow: Implications for atmospheric production and preservation in snow

Evolution of observed ozone, trace gases, and meteorological variables over Arrival Heights, Antarctica &#x00028;77.8&#x000B0;S, 166.7&#x000B0;E&#x00029; during the 2019 Antarctic stratospheric sudden warming

Observational evidence of EPP–NO&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; interaction with chlorine curbing Antarctic ozone loss

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Evolution of observed ozone, trace gases, and meteorological variables over Arrival Heights, Antarctica (77.8°S, 166.7°E) during the 2019 Antarctic stratospheric sudden warming

Observational evidence of EPP–NO<sub><i>x</i></sub> interaction with chlorine curbing Antarctic ozone loss