Two mechanisms of stratospheric ozone loss in the Northern Hemisphere, studied using data assimilation of Odin/SMR atmospheric observations

Sagi, Kazutoshi; Pérot, Kristell; Murtagh, Donal; Orsolini, Yvan

doi:10.5194/acp-17-1791-2017

Cited by 9 publications

(10 citation statements)

References 51 publications

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“…In winters when the polar vortex is unstable and small or disturbed the Brewer-Dobson circulation brings more NO x -rich air to the polar vortex than usual. Hence the ozone loss in the 2012/13 winter was produced mostly by NO x chemistry as shown previously by e.g., Sagi et al (2017). The total ozone column loss in this winter remained smaller than in cold years, when the ozone depletion is driven by halogens.…”

supporting

confidence: 67%

“…In the cold 20 winters the polar vortex is stable and more PSCs are formed and halogens can destroy ozone. Warm conditions in the winter stratosphere are often due to SSW, which allows NO x -rich air masses from the mesosphere to enter the vortex and take part in the ozone depletion (Sagi et al, 2017). Cold winters differ from the warm winters when looking the ozone loss and the fraction of ozone loss initiated by heterogeneous chemistry.…”

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confidence: 99%

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Linking the uncertainty in simulated arctic ozone losses to modelling of tropical stratospheric water vapour

Thölix

Karpechko

Backman

et al. 2018

Preprint

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Abstract. Stratospheric water vapour influences the chemical ozone loss in the polar stratosphere via controlling the polar stratospheric cloud formation. The amount of water entering the stratosphere through the tropical tropopause differs substantially between chemistry-climate models (CCM). This is because the present-day models, e.g. CCMs, have difficulties in capturing the whole complexity of processes that control the water transport across the tropopause. As a result there are large differences in the stratospheric water vapour between the models. 5In this study we investigate the sensitivity of simulated Arctic ozone loss to the amount of water, which enters the stratosphere through the tropical tropopause. We used a chemical transport model, FinROSE-CTM, forced by ERA-Interim meteorology.The water vapour concentration in the tropical tropopause was varied between 0.5 and 1.6 times the concentration in ERAInterim, which is similar to the range seen in chemistry climate models. The water vapour changes in the tropical tropopause led to about 1.5 ppm less and 2 ppm more water vapour in the Arctic polar vortex compared to the ERA-Interim, respectively. 10We found that the impact of water vapour changes on ozone loss in the Arctic polar vortex depend on the meteorological conditions. Polar stratospheric clouds form in the cold conditions within the Arctic vortex, and chlorine activation on their surface lead to ozone loss. If the cold conditions persist long enough (e.g. in 2010/11), the chlorine activation is nearly complete.In this case addition of water vapour to the stratosphere increased the formation of ICE clouds, but did not increase the chlorine activation and ozone destruction significantly. In the warm winter 2012/13 the impact of water vapour concentration on ozone 15 loss was small, because the ozone loss was mainly NO x induced. In intermediately cold conditions, e.g. 2013/14, the effect of added water vapour was more prominent, and resulted in 2-7 % more ozone loss than in the colder winters. The results show that the simulated water vapour concentration in the tropical tropopause has a significant impact on the Arctic ozone loss and deserves attention in order to improve future projections of ozone layer recovery.

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supporting

confidence: 67%

mentioning

confidence: 99%

Linking the uncertainty in simulated arctic ozone losses to modelling of tropical stratospheric water vapour

Thölix

Karpechko

Backman

et al. 2018

Preprint

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“…The FinROSE-CTM has previously been used to study the impact of meteorological conditions on water vapour trends (Thölix et al, 2016), ozone and NO x chemistry in the mesosphere (Salmi et al, 2011), Arctic polar ozone loss (Karpechko et al, 2013) and the impact of the driver data on the model transport (Thölix et al, 2010). Long-term trends of Arctic and Antarctic ozone losses, past and future, have been investigated by using driving data from a chemistryclimate model (Damski et al, 2007a).…”

Section: Thölix Et Al: Uncertainty In Simulated Arctic Ozone Lossmentioning

confidence: 99%

“…The extent of ICE PSCs simulated by FinROSE was compared to Cloud-Aerosol Lidar and Infrared Path finder Satellite Observation (CALIPSO) data in Thölix et al (2016).The total ozone distribution was compared to data from Total Ozone Mapping Spectrometer (TOMS) and the Ozone Monitoring Instrument (OMI) satellite instruments in Damski et al (2007a), Thölix et al (2010) and Karpechko et al (2013). Salmi et al (2011) compared the NO x and ozone profiles in FinROSE to data from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) instrument.…”

Section: Thölix Et Al: Uncertainty In Simulated Arctic Ozone Lossmentioning

confidence: 99%

Linking uncertainty in simulated Arctic ozone loss to uncertainties in modelled tropical stratospheric water vapour

et al. 2018

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Abstract. Stratospheric water vapour influences the chemical ozone loss in the polar stratosphere via control of the polar stratospheric cloud formation. The amount of water vapour entering the stratosphere through the tropical tropopause differs substantially between simulations from chemistry–climate models (CCMs). This is because the present-day models, e.g. CCMs, have difficulties in capturing the whole complexity of processes that control the water transport across the tropopause. As a result there are large differences in the stratospheric water vapour between the models. In this study we investigate the sensitivity of simulated Arctic ozone loss to the simulated amount of water vapour that enters the stratosphere through the tropical tropopause. We used a chemical transport model, FinROSE-CTM, forced by ERA-Interim meteorology. The water vapour concentration in the tropical tropopause was varied between 0.5 and 1.6 times the concentration in ERA-Interim, which is similar to the range seen in chemistry–climate models. The water vapour changes in the tropical tropopause led to about 1.5 ppmv less and 2 ppmv more water vapour in the Arctic polar vortex compared to the ERA-Interim, respectively. The change induced in the water vapour concentration in the tropical tropopause region was seen as a nearly one-to-one change in the Arctic polar vortex. We found that the impact of water vapour changes on ozone loss in the Arctic polar vortex depends on the meteorological conditions. The strongest effect was in intermediately cold stratospheric winters, such as the winter of 2013/2014, when added water vapour resulted in 2 %–7 % more ozone loss due to the additional formation of polar stratospheric clouds (PSCs) and associated chlorine activation on their surface, leading to ozone loss. The effect was less pronounced in cold winters such as the 2010/2011 winter because cold conditions persisted long enough for a nearly complete chlorine activation, even in simulations with prescribed stratospheric water vapour amount corresponding to the observed values. In this case addition of water vapour to the stratosphere led to increased areas of ICE PSCs but it did not increase the chlorine activation and ozone destruction significantly. In the warm winter of 2012/2013 the impact of water vapour concentration on ozone loss was small because the ozone loss was mainly NOx-induced. The results show that the simulated water vapour concentration in the tropical tropopause has a significant impact on the Arctic ozone loss and therefore needs to be well simulated in order to improve future projections of the recovery of the ozone layer.

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“…The stratospheric O 3 destruction by EEP is mostly related to the transported NO x from higher altitude by meridional circulation (Baumgaertner et al, ; Damiani et al, ; Randall et al, ). The O 3 destruction during a major SSW can also be generated by horizontal mixing of NO x ‐rich air from lower latitudes (Sagi et al, ). In order to identify the effect on O 3 destruction by EEP‐induced NO x alone, we will focus on the period of weak horizontal mixing in December.…”

Section: Discussionmentioning

confidence: 99%

Responses of Nitrogen Oxide to High‐Speed Solar Wind Stream in the Polar Middle Atmosphere

et al. 2018

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During high-speed solar wind stream (HSS) events, energetic electrons from the Earth's inner magnetosphere transfer solar wind energy to the high-latitude upper atmosphere, which may affect chemical compositions in the region. We conduct a study on the production of nitrogen oxides (NO x ) in the polar middle atmosphere by energetic electron precipitation (EEP) during HSS events in the period of international polar year 2007-2008 northern winter. During this period, the geomagnetic activity was generally quiet and there were no major solar events, which indicates that the EEPs were mostly associated with HSS events. The electron flux immediately increases with the onset of HSS events and remains elevated during the passage of the events. The estimation of the directly produced NO x by EEPs was attempted by using the correlation between NO x and dynamic tracers such as CO and CH 4 . It was found that the direct effect of EEPs on NO x reaches down to about 55-km altitude and the amount is estimated to be about 2 ppbv. This result indicates that the variations of polar stratospheric NO x in winter are mostly associated with dynamical processes such as vertical transport and horizontal mixing. We also found that the middle atmospheric O 3 depletion during HSS events seems to be related to the EEP-induced NO x at least in the uppermost stratosphere in the polar region. Another important mechanism by particle precipitation is the formation of odd hydrogen, HO x = H + OH + HO 2 , from water vapor (H 2 O) via positive ion chemistry involving water clusters LEE ET AL.9788

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Two mechanisms of stratospheric ozone loss in the Northern Hemisphere, studied using data assimilation of Odin/SMR atmospheric observations

Cited by 9 publications

References 51 publications

Linking the uncertainty in simulated arctic ozone losses to modelling of tropical stratospheric water vapour

Linking the uncertainty in simulated arctic ozone losses to modelling of tropical stratospheric water vapour

Linking uncertainty in simulated Arctic ozone loss to uncertainties in modelled tropical stratospheric water vapour

Responses of Nitrogen Oxide to High‐Speed Solar Wind Stream in the Polar Middle Atmosphere

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