scholarly journals Twisting turning and pulsating of the Antarctic ozone hole, as revealed by TOMS data

MAUSAM ◽  
2021 ◽  
Vol 52 (2) ◽  
pp. 397-412
Author(s):  
R. P. KANE ◽  
C. CASICCIA
Keyword(s):  
Rotation Period ◽  
Polar Vortex ◽  
Major Axis ◽  
Ozone Hole ◽  
Wave Number ◽  
Full Rotation ◽  
Antarctic Ozone ◽  
Using Data ◽  
Pressure Changes ◽  
The Antarctic

Using data from TOMS!Nimbus7 and Meteor 3, the evolution of Antarctic ozone holes during the southern springs of 1992, 1993, 1994 was studied. At the South Pole, the evolution was mostly smooth, a steady decrease up to about September end and a steady recovery up to about December end. At latitudes near 65° S, the ozone levels (~220 DU) at different latitudes and longitudes showed fluctuations compatible with passing of a noncircular (oval) ! vortex boundary (two ends of a major axis of an ellipse), with a rotation period of -15 days (full rotation period ~30 days) in 1992 and ~17 days (full rotation period ~34 days) in 1994, different from the 2-3 weeks reported by earlier workers. However, the rotation was not with uniform speeds. During a full rotation, the speeds varied sometimes from almost zero (stalling) for a few days to ~20° per day during other intervals. Outside the oval boundary, often there were, depletions with spacings of a few (5-8) days, extending to lower latitudes up to ~30° S, indicating corrugations in the oval boundary, probably due to the effects of synoptic disturbances on total ozone through tropopause pressure changes and/or I ozone mini- holes caused by anticyclonic tropospheric forcing under the southern polar vortex. The shape of the ozone hole changed from elliptic to almost circular and vice versa within a few days and the area also changed by ~15-20%. Thus, the ozone hole was twisting, turning and pulsating, probably due to a varying strength of the wave number 2 component of the wind system prevailing there.

scholarly journals Rotating tongues (Protrudences) of ozone- poor air in the Antarctic ozone hole, sweeping over lower latitudes : signatures in ground-based Dobson data

MAUSAM ◽  
2021 ◽  
Vol 50 (3) ◽  
pp. 269-282
Author(s):  
R. P. KANE
Keyword(s):  
Total Ozone ◽  
Rotation Period ◽  
Polar Vortex ◽  
Boundary Edge ◽  
Steady Decrease ◽  
Antarctic Ozone ◽  
Using Data ◽  
Pressure Changes ◽  
The Antarctic ◽  
Ozone Levels

Using data from ground-based Dobson spectrophotometers, the evolution of Antarctic ozone holes during the southern springs of 1992, 1993, 1994 and 1995 was studied, At the South Pole, the evolution was mostly smooth, steady decrease up to about September end and a steady recovery up to about December end, At latitudes near 65°5, the ozone levels at different latitudes and longitudes showed fluctuations compatible with passing of a noncircular (oval) vortex boundary, (edge, rotating tongue), with a rotation period of 15-20 days, However, often there were depletions in-between, extending to lower latitudes up to ~30°S, indicating corrugations in the oval boundary with effects equivalent to those of more than one rotating tongue, There were other short- spaced (5-8 days) depletions, not necessarily simultaneous at different latitudes in the same longitude, and more copious at lower latitudes, probably indicating the effects of synoptic disturbances on total ozone through tropopause pressure changes and/or ozone mini-holes caused by anticyclonic tropospheric forcing under the southern polar vortex.

scholarly journals The Antarctic ozone hole during 2017

2019 ◽  
Vol 69 (1) ◽  
pp. 29
Author(s):  
Andrew R. Klekociuk ◽  
Matthew B. Tully ◽  
Paul B. Krummel ◽  
Oleksandr Evtushevsky ◽  
Volodymyr Kravchenko ◽  
...  
Keyword(s):  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Wave Activity ◽  
Ozone Hole ◽  
Quasi Biennial Oscillation ◽  
Ozone Loss ◽  
Hole Making ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
Antarctic Ozone Hole

We review the 2017 Antarctic ozone hole, making use of various meteorological reanalyses, and in-situ, satellite and ground-based measurements of ozone and related trace gases, and ground-based measurements of ultraviolet radiation. The 2017 ozone hole was associated with relatively high-ozone concentrations over the Antarctic region compared to other years, and our analysis ranked it in the smallest 25% of observed ozone holes in terms of size. The severity of stratospheric ozone loss was comparable with that which occurred in 2002 (when the stratospheric vortex exhibited an unprecedented major warming) and most years prior to 1989 (which were early in the development of the ozone hole). Disturbances to the polar vortex in August and September that were associated with intervals of anomalous planetary wave activity resulted in significant erosion of the polar vortex and the mitigation of the overall level of ozone depletion. The enhanced wave activity was favoured by below-average westerly winds at high southern latitudes during winter, and the prevailing easterly phase of the quasi-biennial oscillation (QBO). Using proxy information on the chemical make-up of the polar vortex based on the analysis of nitrous oxide and the likely influence of the QBO, we suggest that the concentration of inorganic chlorine, which plays a key role in ozone loss, was likely similar to that in 2014 and 2016, when the ozone hole was larger than that in 2017. Finally, we found that the overall severity of Antarctic ozone loss in 2017 was largely dictated by the timing of the disturbances to the polar vortex rather than interannual variability in the level of inorganic chlorine.

scholarly journals Future Antarctic ozone recovery rates in September–December predicted by CCMVal-2 model simulations

2012 ◽  
Vol 12 (8) ◽  
pp. 18959-18991 ◽  
Author(s):  
J. M. Siddaway ◽  
S. V. Petelina ◽  
D. Karoly ◽  
A. R. Klekociuk ◽  
R. J. Dargaville
Keyword(s):  
Climate Model ◽  
Polar Vortex ◽  
Early Summer ◽  
Ozone Hole ◽  
Recovery Rates ◽  
Large Variability ◽  
Model Simulations ◽  
Hole Level ◽  
Antarctic Ozone ◽  
The Antarctic

Abstract. Chemistry-climate model validation phase 2 (CCMVal-2) model simulations are used to analyze Antarctic ozone recovery rates in 2000–2100 during local spring and early summer, both vertically integrated and at several pressure levels in the lower stratosphere. Multi-model median trends of monthly zonal mean total ozone column (TOC), ozone volume mixing ratio (VMR), wind speed and temperature poleward of 60° S are investigated. Median values are used to account for large variability in models, and the associated uncertainty is calculated using a bootstrapping technique. According to the selected ten CCMVal-2 models, Antarctic TOC will return to its pre-ozone hole level, taken as an average of 1970–1979 values, between 2065 and 2075 in September–November, and around 2050 in December. In 2000–2020, an increase in TOC is much smaller than in later years, and this is especially evident for December. Although the December TOC recovers to its pre-ozone hole levels earlier compared to all spring months (as the December ozone depletion was much lower), the rate of December TOC increase, is slower than that for all spring months. Projected trends in ozone VMR, temperature and winds at several pressure levels are analyzed in order to attribute the projected rate of December TOC recovery, as well as to investigate future changes in the Antarctic atmosphere in general, including some aspects of the polar vortex breakup.

scholarly journals The Antarctic ozone hole during 2014

2019 ◽  
Vol 69 (1) ◽  
pp. 1
Author(s):  
Paul B. Krummel ◽  
Andrew R. Klekociuk ◽  
Matthew B. Tully ◽  
H. Peter Gies ◽  
Simon P. Alexander ◽  
...  
Keyword(s):  
Polar Vortex ◽  
Ultra Violet ◽  
Ozone Hole ◽  
Ultra Violet Radiation ◽  
Hole Making ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
Violet Radiation ◽  
Antarctic Ozone Hole

We review the 2014 Antarctic ozone hole, making use of a variety of ground-based and space-based measurements of ozone and ultra-violet radiation, supplemented by meteorological reanalyses. Although the polar vortex was relatively stable in 2014 and persisted some weeks longer into November than was the case in 2012 or 2013, the vortex temperature was close to the long-term mean in September and October with modest warming events occurring in both months, preventing severe depletion from taking place. Of the seven metrics reported here, all were close to their respective median values of the 1979–2014 record, being ranked between 16th and 21st of the 35 years for which adequate satellite observations exist.

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.

The discovery of the Antarctic ozone hole

Nature ◽  
2019 ◽  
Vol 575 (7781) ◽  
pp. 46-47 ◽  
Author(s):  
Susan Solomon
Keyword(s):  
Ozone Hole ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
Antarctic Ozone Hole

scholarly journals Evolution of Antarctic ozone in September–December predicted by CCMVal-2 model simulations for the 21st century

2013 ◽  
Vol 13 (8) ◽  
pp. 4413-4427 ◽  
Author(s):  
J. M. Siddaway ◽  
S. V. Petelina ◽  
D. J. Karoly ◽  
A. R. Klekociuk ◽  
R. J. Dargaville
Keyword(s):  
21St Century ◽  
Climate Model ◽  
Polar Vortex ◽  
Early Summer ◽  
Slow Increase ◽  
Large Variability ◽  
Model Simulations ◽  
Antarctic Ozone ◽  
Decadal Rate ◽  
The Antarctic

Abstract. Chemistry-Climate Model Validation phase 2 (CCMVal-2) model simulations are used to analyze Antarctic ozone increases in 2000–2100 during local spring and early summer, both vertically integrated and at several pressure levels in the lower stratosphere. Multi-model median trends of monthly zonal mean total ozone column (TOC), ozone volume mixing ratio (VMR), wind speed and temperature poleward of 60° S are investigated. Median values are used to account for large variability in models, and the associated uncertainty is calculated using a bootstrapping technique. According to the trend derived from the twelve CCMVal-2 models selected, Antarctic TOC will not return to a 1965 baseline, an average of 1960–1969 values, by the end of the 21st century in September–November, but will return in ~2080 in December. The speed of December ozone depletion before 2000 was slower compared to spring months, and thus the decadal rate of December TOC increase after 2000 is also slower. Projected trends in December ozone VMR at 20–100 hPa show a much slower rate of ozone recovery, particularly at 50–70 hPa, than for spring months. Trends in temperature and winds at 20–150 hPa are also analyzed in order to attribute the projected slow increase of December ozone and to investigate future changes in the Antarctic atmosphere in general, including some aspects of the polar vortex breakup.

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