scholarly journals The Relationship between Polar Vortex and Ozone Depletion in the Antarctic Stratosphere during the Period 1979–2016

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Yu Zhang ◽  
Jing Li ◽  
Libo Zhou
Keyword(s):  
Ozone Depletion ◽  
Morphological Changes ◽  
Negative Relationship ◽  
Polar Vortex ◽  
Correlation Coefficients ◽  
Horizontal Distribution ◽  
Total Column Ozone ◽  
Column Ozone ◽  
The Antarctic ◽  
Breakup Time

As the most prominent feature of the polar stratosphere, polar vortex results in widespread changes in the climate system, especially in the ozone variation. In this study, the linkage between polar vortex and ozone depletion in Antarctic stratosphere during the period 1979–2016 is investigated; we calculated the averaged total column ozone within the polar vortex based on the vortex edge (−28.8 PVU PV contour) instead of the geographical region defined by latitude and longitude. Results from the spatial patterns of ozone and polar vortex suggest that the morphological changes of polar vortex can impact the horizontal distribution of ozone and the ozone within the polar vortex experiences a severe depletion in spring. The negative relationship between ozone and polar vortex in terms of vortex area, strength, and breakup time is significant with the correlation coefficients of −0.57, −0.68, and −0.76, respectively. The breakup time of polar vortex plays an important role in the relation between polar vortex and ozone depletion with the highest-value correlation coefficient among three polar vortex parameters. Furthermore, the possible mechanism for this relationship is also discussed in this article.

scholarly journals Antarctic ozone depletion between 1960 and 1980 in observations and chemistry–climate model simulations

2016 ◽  
Vol 16 (24) ◽  
pp. 15619-15627 ◽  
Author(s):  
Ulrike Langematz ◽  
Franziska Schmidt ◽  
Markus Kunze ◽  
Gregory E. Bodeker ◽  
Peter Braesicke
Keyword(s):  
Ozone Depletion ◽  
Climate Model ◽  
Total Column Ozone ◽  
Antarctic Ozone ◽  
Climate Model Simulations ◽  
Ozone Depleting Substances ◽  
Column Ozone ◽  
The Antarctic ◽  
Total Column

Abstract. The year 1980 has often been used as a benchmark for the return of Antarctic ozone to conditions assumed to be unaffected by emissions of ozone-depleting substances (ODSs), implying that anthropogenic ozone depletion in Antarctica started around 1980. Here, the extent of anthropogenically driven Antarctic ozone depletion prior to 1980 is examined using output from transient chemistry–climate model (CCM) simulations from 1960 to 2000 with prescribed changes of ozone-depleting substance concentrations in conjunction with observations. A regression model is used to attribute CCM modelled and observed changes in Antarctic total column ozone to halogen-driven chemistry prior to 1980. Wintertime Antarctic ozone is strongly affected by dynamical processes that vary in amplitude from year to year and from model to model. However, when the dynamical and chemical impacts on ozone are separated, all models consistently show a long-term, halogen-induced negative trend in Antarctic ozone from 1960 to 1980. The anthropogenically driven ozone loss from 1960 to 1980 ranges between 26.4 ± 3.4 and 49.8 ± 6.2 % of the total anthropogenic ozone depletion from 1960 to 2000. An even stronger ozone decline of 56.4 ± 6.8 % was estimated from ozone observations. This analysis of the observations and simulations from 17 CCMs clarifies that while the return of Antarctic ozone to 1980 values remains a valid milestone, achieving that milestone is not indicative of full recovery of the Antarctic ozone layer from the effects of ODSs.

scholarly journals Indicators of Antarctic ozone depletion: 1979 to 2019

2020 ◽  
Author(s):  
Greg E. Bodeker ◽  
Stefanie Kremser
Keyword(s):  
Ozone Depletion ◽  
Learning Algorithm ◽  
Total Column Ozone ◽  
Secular Variability ◽  
Antarctic Ozone ◽  
Time Changes ◽  
Ozone Depleting Substances ◽  
Winter Time ◽  
Column Ozone ◽  
The Antarctic

Abstract. The National Institute of Water and Atmospheric Research/Bodeker Scientific (NIWA-BS) total column ozone (TCO) database, and the associated BS-filled TCO database, have been updated to cover the period 1979 to 2019, bringing both to version 3.5.1 (V3.5.1). The BS-filled database builds on the NIWA-BS database by using a machine-learning algorithm to fill spatial and temporal data gaps to provide gap-free TCO fields over Antarctic. These filled TCO fields then provide a more complete picture of winter-time changes in the ozone layer over Antarctica. The BS-filled database has been used to calculate continuous, homogeneous time series of indicators of Antarctic ozone depletion from 1979 to 2019, including (i) daily values of the ozone mass deficit based on TCO below a 220 DU threshold, (ii) daily measures of the area over Antarctica where TCO levels are below 150 DU, below 220 DU, more than 30 % below 1979 to 1981 climatological means, and more than 50 % below 1979 to 1981 climatological means, (iii) the date of disappearance of 150 DU TCO values, 220 DU TCO values, values 30 % or more below 1979 to 1981 climatological means, and values 50 % or more below 1979 to 1981 climatological means, for each year, and (iv) daily minimum TCO values over the range 75° S to 90° S equivalent latitude. Since both the NIWA-BS and BS-filled databases provide uncertainties on every TCO value, the Antarctic ozone depletion metrics are provided, for the first time, with fully traceable uncertainties. To gain insight into how the vertical distribution of ozone over Antarctica has changed over the past 36 years, ozone concentrations, combined and homogenized from several satellite-based ozone monitoring instruments as well as the global ozonesonde network, were also analysed. A robust attribution to changes in the drivers of long-term secular variability in these metrics has not been performed in this analysis. As a result, statements about the recovery of Antarctic TCO from the effects of ozone depleting substances cannot be made. That said, there are clear indications of a change in trend in many of the metrics reported on here around the turn of the century, close to when Antarctic stratospheric concentrations of chlorine and bromine peaked.

scholarly journals Improvements to stratospheric chemistry scheme in the UM-UKCA (v10.7) model: solar cycle and heterogeneous reactions

2018 ◽  
Author(s):  
Fraser Dennison ◽  
James Keeble ◽  
Olaf Morgenstern ◽  
Guang Zeng ◽  
N. Luke Abraham ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Polar Vortex ◽  
Heterogeneous Reactions ◽  
The Arctic ◽  
Cold Bias ◽  
Total Column Ozone ◽  
Antarctic Polar Vortex ◽  
Column Ozone ◽  
The Antarctic ◽  
Total Column

Abstract. Improvements are made to two areas of the United Kingdom Chemistry and Aerosol (UKCA) module, which forms part of the Met Office Unified Model (UM) used for weather and climate applications. Firstly, a solar cycle is added to the photolysis scheme. The effect on total column ozone of this addition was found to be around 1–2 % in mid-latitude and equatorial regions in phase with the solar cycle. Secondly, reactions occurring on the surfaces of polar stratospheric clouds and sulfate aerosol are updated and extended by modification of the uptake coefficients of five existing reactions and the addition of a further eight reactions involving bromine species. These modifications are shown to reduce the overabundance of modeled total-column ozone in the Arctic during October to February, southern mid-latitudes during August, and the Antarctic during September. Antarctic springtime ozone depletion is shown to be enhanced by 25 DU on average, which now causes the ozone hole to be somewhat too deep compared to observations. We show that this is in part due to a cold bias of the Antarctic polar vortex in the model.

scholarly journals Improvements to stratospheric chemistry scheme in the UM-UKCA (v10.7) model: solar cycle and heterogeneous reactions

2019 ◽  
Vol 12 (3) ◽  
pp. 1227-1239 ◽  
Author(s):  
Fraser Dennison ◽  
James Keeble ◽  
Olaf Morgenstern ◽  
Guang Zeng ◽  
N. Luke Abraham ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Polar Vortex ◽  
Heterogeneous Reactions ◽  
The Arctic ◽  
Cold Bias ◽  
Total Column Ozone ◽  
Antarctic Polar Vortex ◽  
Column Ozone ◽  
The Antarctic ◽  
Total Column

Abstract. Improvements are made to two areas of the United Kingdom Chemistry and Aerosol (UKCA) module, which forms part of the Met Office Unified Model (UM) used for weather and climate applications. Firstly, a solar cycle is added to the photolysis scheme. The effect on total column ozone of this addition was found to be around 1 %–2 % in midlatitude and equatorial regions, in phase with the solar cycle. Secondly, reactions occurring on the surfaces of polar stratospheric clouds and sulfate aerosol are updated and extended by modification of the uptake coefficients of five existing reactions and the addition of a further eight reactions involving bromine species. These modifications are shown to reduce the overabundance of modelled total column ozone in the Arctic during October to February, southern midlatitudes during August and the Antarctic during September. Antarctic springtime ozone depletion is shown to be enhanced by 25 DU on average, which now causes the ozone hole to be somewhat too deep compared to observations. We show that this is in part due to a cold bias of the Antarctic polar vortex in the model.

scholarly journals Indicators of Antarctic ozone depletion: 1979 to 2019

2021 ◽  
Vol 21 (7) ◽  
pp. 5289-5300
Author(s):  
Greg E. Bodeker ◽  
Stefanie Kremser
Keyword(s):  
Ozone Depletion ◽  
Learning Algorithm ◽  
Turn Of The Century ◽  
Total Column Ozone ◽  
Secular Variability ◽  
Antarctic Ozone ◽  
Ozone Depleting Substances ◽  
Column Ozone ◽  
The Antarctic ◽  
First Time

Abstract. The National Institute of Water and Atmospheric Research/Bodeker Scientific (NIWA–BS) total column ozone (TCO) database and the associated BS-filled TCO database have been updated to cover the period 1979 to 2019, bringing both to version 3.5.1 (V3.5.1). The BS-filled database builds on the NIWA–BS database by using a machine-learning algorithm to fill spatial and temporal data gaps to provide gap-free TCO fields over Antarctica. These filled TCO fields then provide a more complete picture of wintertime changes in the ozone layer over Antarctica. The BS-filled database has been used to calculate continuous, homogeneous time series of indicators of Antarctic ozone depletion from 1979 to 2019, including (i) daily values of the ozone mass deficit based on TCO below a 220 DU threshold; (ii) daily measures of the area over Antarctica where TCO levels are below 150 DU, below 220 DU, more than 30 % below 1979 to 1981 climatological means, and more than 50 % below 1979 to 1981 climatological means; (iii) the date of disappearance of 150 DU TCO values, 220 DU TCO values, values 30 % or more below 1979 to 1981 climatological means, and values 50 % or more below 1979 to 1981 climatological means, for each year; and (iv) daily minimum TCO values over the range 75 to 90∘ S equivalent latitude. Since both the NIWA–BS and BS-filled databases provide uncertainties on every TCO value, the Antarctic ozone depletion metrics are provided, for the first time, with fully traceable uncertainties. To gain insight into how the vertical distribution of ozone over Antarctica has changed over the past 36 years, ozone concentrations, combined and homogenized from several satellite-based ozone monitoring instruments as well as the global ozonesonde network, were also analysed. A robust attribution to changes in the drivers of long-term secular variability in these metrics has not been performed in this analysis. As a result, statements about the recovery of Antarctic TCO from the effects of ozone-depleting substances cannot be made. That said, there are clear indications of a change in trend in many of the metrics reported on here around the turn of the century, close to when Antarctic stratospheric concentrations of chlorine and bromine peaked.

scholarly journals The simulation of the Antarctic ozone hole by chemistry-climate models

2009 ◽  
Vol 9 (17) ◽  
pp. 6363-6376 ◽  
Author(s):  
H. Struthers ◽  
G. E. Bodeker ◽  
J. Austin ◽  
S. Bekki ◽  
I. Cionni ◽  
...  
Keyword(s):  
Climate Models ◽  
Polar Vortex ◽  
Ozone Hole ◽  
Total Column Ozone ◽  
Hole Area ◽  
Antarctic Ozone ◽  
Column Ozone ◽  
The Antarctic ◽  
Total Column ◽  
Antarctic Ozone Hole

Abstract. While chemistry-climate models are able to reproduce many characteristics of the global total column ozone field and its long-term evolution, they have fared less well in simulating the commonly used diagnostic of the area of the Antarctic ozone hole i.e. the area within the 220 Dobson Unit (DU) contour. Two possible reasons for this are: (1) the underlying Global Climate Model (GCM) does not correctly simulate the size of the polar vortex, and (2) the stratospheric chemistry scheme incorporated into the GCM, and/or the model dynamics, results in systematic biases in the total column ozone fields such that the 220 DU contour is no longer appropriate for delineating the edge of the ozone hole. Both causes are examined here with a view to developing ozone hole area diagnostics that better suit measurement-model inter-comparisons. The interplay between the shape of the meridional mixing barrier at the edge of the vortex and the meridional gradients in total column ozone across the vortex edge is investigated in measurements and in 5 chemistry-climate models (CCMs). Analysis of the simulation of the polar vortex in the CCMs shows that the first of the two possible causes does play a role in some models. This in turn affects the ability of the models to simulate the large observed meridional gradients in total column ozone. The second of the two causes also strongly affects the ability of the CCMs to track the observed size of the ozone hole. It is shown that by applying a common algorithm to the CCMs for selecting a delineating threshold unique to each model, a more appropriate diagnostic of ozone hole area can be generated that shows better agreement with that derived from observations.

scholarly journals Antarctic Ozone Depletion between 1960 and 1980 in Observations and Chemistry-Climate Model Simulations

2016 ◽  
Author(s):  
Ulrike Langematz ◽  
Franziska Schmidt ◽  
Markus Kunze ◽  
Peter Braesicke ◽  
Gregory E. Bodeker
Keyword(s):  
Ozone Depletion ◽  
Climate Model ◽  
Total Column Ozone ◽  
Antarctic Ozone ◽  
Climate Model Simulations ◽  
Ozone Depleting Substances ◽  
Winter Time ◽  
Column Ozone ◽  
The Antarctic

Abstract. The year 1980 has often been used as a benchmark for the return of Antarctic ozone to conditions assumed to be unaffected by emissions of ozone depleting substances (ODSs), implying that anthropogenic ozone depletion in Antarctica started around 1980. Here, the extent of anthropogenically-driven Antarctic ozone depletion prior to 1980 is examined using output from transient Chemistry-Climate Model (CCM) simulations from 1960 to 2000 with prescribed changes of ozone depleting substance concentrations in conjunction with observations. A regression model is used to attribute CCM modelled and observed changes in Antarctic total column ozone to halogen-driven chemistry prior to 1980. Winter-time Antarctic ozone is strongly affected by dynamical processes that vary in amplitude from year to year and from model to model. However, when the dynamical and chemical impacts on ozone are separated, all models consistently show a long-term, halogen-induced negative trend in Antarctic ozone from 1960 to 1980. The anthropogenically-driven ozone loss from 1960 to 1980 ranges between 26.4 ± 3.4 % and 49.8 ± 6.2 % of the total anthropogenic ozone depletion from 1960 to 2000. An even stronger ozone decline of 56.4 ± 6.8 % was estimated from ozone observations. This analysis of the observations and simulations from 17 CCMs clarifies that while the return of Antarctic ozone to 1980 values remains a valid milestone, achieving that milestone is not indicative of full recovery of the Antarctic ozone layer from the effects of ODSs.

scholarly journals Ozone Chemistry during the 2002 Antarctic Vortex Split

2005 ◽  
Vol 62 (3) ◽  
pp. 860-870 ◽  
Author(s):  
Jens-Uwe Grooß ◽  
Paul Konopka ◽  
Rolf Müller
Keyword(s):  
Ozone Depletion ◽  
Polar Region ◽  
Polar Vortex ◽  
Dilution Effect ◽  
Lagrangian Model ◽  
Chemical Effect ◽  
Small Scale ◽  
Air Masses ◽  
Antarctic Polar Vortex ◽  
The Antarctic

Abstract In September 2002, the Antarctic polar vortex was disturbed, and it split into two parts caused by an unusually early stratospheric major warming. This study discusses the chemical consequences of this event using the Chemical Lagrangian Model of the Stratosphere (CLaMS). The chemical initialization of the simulation is based on Halogen Occultation Experiment (HALOE) measurements. Because of its Lagrangian nature, CLaMS is well suited for simulating the small-scale filaments that evolve during this period. Filaments of vortex origin in the midlatitudes were observed by HALOE several times in October 2002. The results of the simulation agree well with these HALOE observations. The simulation further indicates a very rapid chlorine deactivation that is triggered by the warming associated with the split of the vortex. Correspondingly, the ozone depletion rates in the polar vortex parts rapidly decrease to zero. Outside the polar vortex, where air masses of midlatitude origin were transported to the polar region, the simulation shows high ozone depletion rates at the 700-K level caused mainly by NOx chemistry. Owing to the major warming in September 2002, ozone-poor air masses were transported into the midlatitudes and caused a decrease of midlatitude ozone by 5%–15%, depending on altitude. Besides this dilution effect, there was no significant additional chemical effect. The net chemical ozone depletion in air masses of vortex origin was low and did not differ significantly from that of midlatitude air, in spite of the different chemical composition of the two types of air masses.

scholarly journals Options to accelerate ozone recovery: ozone and climate benefits

2010 ◽  
Vol 10 (16) ◽  
pp. 7697-7707 ◽  
Author(s):  
J. S. Daniel ◽  
E. L. Fleming ◽  
R. W. Portmann ◽  
G. J. M. Velders ◽  
C. H. Jackman ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Radiative Forcing ◽  
Montreal Protocol ◽  
N2o Emissions ◽  
Total Column Ozone ◽  
Potential Impact ◽  
Ozone Depleting Substances ◽  
Column Ozone ◽  
The Impact ◽  
Total Column

Abstract. Hypothetical reductions in future emissions of ozone-depleting substances (ODSs) and N2O are evaluated in terms of effects on equivalent effective stratospheric chlorine (EESC), globally-averaged total column ozone, and radiative forcing through 2100. Due to the established success of the Montreal Protocol, these actions can have only a fraction of the impact on ozone depletion that regulations already in force have had. If all anthropogenic ODS and N2O emissions were halted beginning in 2011, ozone is calculated to be higher by about 1–2% during the period 2030–2100 compared to a case of no additional restrictions. Direct radiative forcing by 2100 would be about 0.23 W/m2 lower from the elimination of anthropogenic N2O emissions and about 0.005 W/m2 lower from the destruction of the chlorofluorocarbon (CFC) bank. Due to the potential impact of N2O on future ozone levels, we provide an approach to incorporate it into the EESC formulation, which is used extensively in ozone depletion analyses. The ability of EESC to describe total ozone changes arising from additional ODS and N2O controls is also quantified.

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