A hole in the Arctic polar ozone layer during March 1986

1989 ◽  
Vol 67 (2-3) ◽  
pp. 161-165 ◽  
Author(s):  
W. F. J. Evans

A craterlike structure or "hole" in the Arctic polar ozone layer during March 1986 has been observed in the total ozone images from the total ozone mapping spectrometer instrument on the NIMBUS 7 satellite. Observations from ozonesondes in the vicinity of this crater show a depleted region in the altitude profile from 10 to 16 km. This altitude region of depleted ozone is similar to the depleted layer observed from 12 to 18 km within the Antarctic ozone hole. A comparison has been made between the ozone altitude profile outside the crater at Resolute, N.W.T., Canada (75°N), and the ozone altitude profile inside the crater at Lindenberg, German Democratic Republic, (55°N). The difference in these profiles demonstrates that the crater is due to a process that has altered the altitude distribution of ozone in the 10–16 km region. This depletion could be attributed to either a vertical circulation or a chemical-depletion process.

1990 ◽  
Vol 68 (10) ◽  
pp. 1113-1121
Author(s):  
W. F. J. Evans ◽  
A. E. Walker ◽  
F. E. Bunn

The presence of a thinned area or craterlike feature in the Arctic polar ozone layer during March, 1986 has been reported previously (Can. J. Phys. 67, 161 (1989)). In this paper the morphology of the reappearance of the crater from January to March, 1989 is described. It appeared over northern Europe in late January and moved over western Canada in late February. The minimum value of ozone in the crater floor had fallen from 300 DU (1 Dobson unit (DU) = 0.01 mm) in 1979 to a new low of less than 200 DU in 1989, which is similar to the thinned total ozone columns observed within the Antarctic ozone hole. Analysis of the available total ozone mapping spectrometer ozone measurements indicates that the crater could be explained by a combination of two mechanisms; a chemical process, which depleted the ozone concentrations at altitudes in the 14–22 km region, and a transport process, which shifted the altitude distribution of ozone upwards such as a vertical circulation cell. Although the Arctic ozone crater is similar in several aspects to the Antarctic ozone hole, there remain several differences; the issue is whether the crater and the hole are manifestations of the same phenomenon. We consider that the Arctic ozone crater is mainly produced by dynamic redistribution driven by tropospheric circulation features.


2021 ◽  
Author(s):  
Ville Maliniemi ◽  
Pavle Arsenovic ◽  
Hilde Nesse Tyssøy ◽  
Christine Smith-Johnsen ◽  
Daniel R. Marsh

<p>Ozone is expected to fully recover from the CFC-era by the end of the 21st century. Furthermore, because of the anthropogenic climate change, cooler stratosphere accelerates the ozone production and is projected to lead to a super recovery. We investigate the ozone distribution over the 21st century with four different future scenarios using simulations of the Whole Atmosphere Community Climate Model (WACCM). At the end of the 21st century, higher polar ozone levels than pre CFC-era are obtained in scenarios that have highest atmospheric radiative forcing. This is true in the Arctic stratosphere and the Antarctic lower stratosphere. The Antarctic upper stratosphere forms an exception, where different scenarios have similar level of ozone during winter. This results from excess nitrogen oxides (NOx) descending from above in stronger future scenarios. NOx is formed by energetic electron precipitation (EEP) in the thermosphere and the upper mesosphere, and descends faster through the mesosphere in stronger scenarios. This indicates that the EEP indirect effect will be important factor for the future Antarctic ozone evolution, and is potentially able to prevent the super recovery in the upper stratosphere.</p>


2011 ◽  
Vol 11 (2) ◽  
pp. 6555-6599 ◽  
Author(s):  
T. Sonkaew ◽  
C. von Savigny ◽  
K.-U. Eichmann ◽  
M. Weber ◽  
A. Rozanov ◽  
...  

Abstract. Stratospheric ozone profiles are retrieved for the period 2002–2009 from SCIAMACHY measurements of limb-scattered solar radiation in the Hartley and Chappuis absorption bands of ozone. This data set is used to determine the chemical ozone loss in both the Arctic and Antarctic polar vortices using the vortex average method. The chemical ozone loss at isentropic levels between 450 K and 600 K is derived from the difference between observed ozone abundances and the ozone modelled considering diabatic cooling, but no chemical ozone loss. The results show chemical ozone losses of up to 20–40% between the beginning of January and the end of March inside the Arctic polar vortex. Strong inter-annual variability of the Arctic ozone loss is observed, with the cold winters 2004/2005 and 2006/2007 showing the largest chemical ozone losses. The ozone mass loss inside the polar vortex is also estimated. In the coldest Arctic winter 2004/2005 the total ozone mass loss is about 30 million tons inside the polar vortex between the 450 K and 600 K isentropic levels from the beginning of January until the end of March. The Antarctic vortex averaged ozone loss as well as the size of the polar vortex do not vary much from year to year. At the 475 K isentropic level ozone losses of 70–80% between mid-August and mid-November are observed every year inside the vortex, also in the anomalous year 2002. The total ozone mass loss inside the Antarctic polar vortex between the 450 K and 600 K isentropic levels is about 55–75 million tons for the period between mid-August and mid-November. Comparisons of the vertical variation of ozone loss derived from SCIAMACHY observations with several independent techniques for the Arctic winter 2004/2005 show very good agreement.


1991 ◽  
Vol 69 (8-9) ◽  
pp. 1087-1092 ◽  
Author(s):  
F. E. Bunn ◽  
F. W. Thirkettle ◽  
W. F. J. Evans

The data from the NIMBUS-7 TOMS instrument were used to study the Arctic ozone layer in late winter and spring, 1989. This paper presents an analysis of TOMS total ozone values, to produce a picture of the morphology of the Arctic stratospheric ozone crater in winter–spring 1989. The Arctic crater formed in late January when the vortex moved off the pole to over Scandinavia. The TOMS data clearly show the Arctic ozone-crater feature over Scandinavia and the western Soviet Union, on February 2, 1989. It later moved south to Baffin Island and then, in March, down over Toronto, and eventually to western Canada, near Edmonton. A similar, unexpected, crater was present in the Antarctic fall, on March 15, 1989. This phenomenon is mainly produced by dynamic uplift, but there may be ozone depletion occurring as well owing to reduced temperatures.


2008 ◽  
Vol 8 (2) ◽  
pp. 251-264 ◽  
Author(s):  
R. Müller ◽  
J.-U. Grooß ◽  
C. Lemmen ◽  
D. Heinze ◽  
M. Dameris ◽  
...  

Abstract. We investigate the extent to which quantities that are based on total column ozone are applicable as measures of ozone loss in the polar vortices. Such quantities have been used frequently in ozone assessments by the World Meteorological Organization (WMO) and also to assess the performance of chemistry-climate models. The most commonly considered quantities are March and October mean column ozone poleward of geometric latitude 63° and the spring minimum of daily total ozone minima poleward of a given latitude. Particularly in the Arctic, the former measure is affected by vortex variability and vortex break-up in spring. The minimum of daily total ozone minima poleward of a particular latitude is debatable, insofar as it relies on one single measurement or model grid point. We find that, for Arctic conditions, this minimum value often occurs in air outside the polar vortex, both in the observations and in a chemistry-climate model. Neither of the two measures shows a good correlation with chemical ozone loss in the vortex deduced from observations. We recommend that the minimum of daily minima should no longer be used when comparing polar ozone loss in observations and models. As an alternative to the March and October mean column polar ozone we suggest considering the minimum of daily average total ozone poleward of 63° equivalent latitude in spring (except for winters with an early vortex break-up). Such a definition both obviates relying on one single data point and reduces the impact of year-to-year variability in the Arctic vortex break-up on ozone loss measures. Further, this measure shows a reasonable correlation (r=–0.75) with observed chemical ozone loss. Nonetheless, simple measures of polar ozone loss must be used with caution; if possible, it is preferable to use more sophisticated measures that include additional information to disentangle the impact of transport and chemistry on ozone.


2013 ◽  
Vol 13 (10) ◽  
pp. 5299-5308 ◽  
Author(s):  
J.-P. Pommereau ◽  
F. Goutail ◽  
F. Lefèvre ◽  
A. Pazmino ◽  
C. Adams ◽  
...  

Abstract. An unprecedented ozone loss occurred in the Arctic in spring 2011. The details of the event are revisited from the twice-daily total ozone and NO2 column measurements of the eight SAOZ/NDACC (Système d'Analyse par Observation Zénithale/Network for Detection of Atmospheric Composition Changes) stations in the Arctic. It is shown that the total ozone depletion in the polar vortex reached 38% (approx. 170 DU) by the end of March, which is larger than the 30% of the previous record in 1996. Aside from the long extension of the cold stratospheric NAT PSC period, the amplitude of the event is shown to be resulting from a record daily total ozone loss rate of 0.7% d−1 after mid-February, never seen before in the Arctic but similar to that observed in the Antarctic over the last 20 yr. This high loss rate is attributed to the absence of NOx in the vortex until the final warming, in contrast to all previous winters where, as shown by the early increase of NO2 diurnal increase, partial renoxification occurs by import of NOx or HNO3 from the outside after minor warming episodes, leading to partial chlorine deactivation. The cause of the absence of renoxification and thus of high loss rate, is attributed to a vortex strength similar to that of the Antarctic but never seen before in the Arctic. The total ozone reduction on 20 March was identical to that of the 2002 Antarctic winter, which ended around 20 September, and a 15-day extension of the cold period would have been enough to reach the mean yearly amplitude of the Antarctic ozone hole. However there is no sign of trend since 1994, either in PSC (polar stratospheric cloud) volume (volume of air cold enough to allow formation of PSCs), early winter denitrification, late vortex renoxification, and vortex strength or in total ozone loss. The unprecedented large Arctic ozone loss in 2011 appears to result from an extreme meteorological event and there is no indication of possible strengthening related to climate change.


2021 ◽  
Author(s):  
Markus Jesswein ◽  
Heiko Bozem ◽  
Hans-Christoph Lachnitt ◽  
Peter Hoor ◽  
Thomas Wagenhäuser ◽  
...  

Abstract. Inorganic chlorine (Cly) is the sum of the degradation products of long-lived chlorinated source gases. These include the reservoir species (HCl and ClONO2) and active chlorine species (i.e. ClOx). The active chlorine species drive catalytic cycles that deplete ozone in the polar winter stratosphere. This work presents calculations of inorganic chlorine (Cly) derived from chlorinated source gas measurements on board the High Altitude and Long Range Research Aircraft (HALO) during the Southern hemisphere Transport, Dynamic and Chemistry (SouthTRAC) campaign in late winter and early spring 2019. Results are compared to Cly of the Northern Hemisphere derived from measurements of the POLSTRACC-GW-LCYCLE-SALSA (PGS) campaign in the Arctic winter of 2015/2016. A scaled correlation was used for PGS data, since not all source gases were measured. Cly from a scaled correlation was compared to directly determined Cly and agreed well. An air mass classification based on in situ N2O measurements allocates the measurements to the vortex, the vortex boundary region, and mid-latitudes. Although the Antarctic vortex was weakened in 2019 compared to previous years, Cly reached 1687 ± 20 ppt at 385 K, therefore up to around 50 % of total chlorine could be found in inorganic form inside the Antarctic vortex, whereas only 15 % of total chlorine could be found in inorganic form in the southern mid-latitudes. In contrast, only 40 % of total chlorine could be found in inorganic form in the Arctic vortex during PGS and roughly 20 % in the northern mid-latitudes. Differences inside the respective vortex reaches up to 565 ppt more Cly in the Antarctic vortex 2019 than in the Arctic vortex 2016 (at comparable distance to the local tropopause). As far as is known, this is the first comparison of inorganic chlorine within the respective polar vortex. Based on the results of these two campaigns, the difference of Cly inside the respective vortex is significant and larger than reported inter annual variations.


MAUSAM ◽  
2021 ◽  
Vol 48 (3) ◽  
pp. 443-446
Author(s):  
S.K. PESIHN ◽  
P. RAJESH RAO ◽  
S.K. SRIVASTAV

ABSTRACT. Profiles from a series of balloon borne ozonesonde ascents are used to chart the development of the Antarctic depletion over Maitri in the austral spring of 1992. The vertical structure of the ozone layer is discussed, including the presence of stratification, which occurs at all stages of development. The main feature of 1992 ozonesonde flights is depletion of 97% in the months of September and October between 15-23 km, which is unique.    


2021 ◽  
Vol 21 (2) ◽  
pp. 617-633
Author(s):  
Martin Dameris ◽  
Diego G. Loyola ◽  
Matthias Nützel ◽  
Melanie Coldewey-Egbers ◽  
Christophe Lerot ◽  
...  

Abstract. Ozone data derived from the Tropospheric Monitoring Instrument (TROPOMI) sensor on board the Sentinel-5 Precursor satellite show exceptionally low total ozone columns in the polar region of the Northern Hemisphere (Arctic) in spring 2020. Minimum total ozone column values around or below 220 Dobson units (DU) were seen over the Arctic for 5 weeks in March and early April 2020. Usually the persistence of such low total ozone column values in spring is only observed in the polar Southern Hemisphere (Antarctic) and not over the Arctic. These record low total ozone columns were caused by a particularly strong polar vortex in the stratosphere with a persistent cold stratosphere at higher latitudes, a prerequisite for ozone depletion through heterogeneous chemistry. Based on the ERA5, which is the fifth generation of the European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis, the Northern Hemisphere winter 2019/2020 (from December to March) showed minimum polar cap temperatures consistently below 195 K around 20 km altitude, which enabled enhanced formation of polar stratospheric clouds. The special situation in spring 2020 is compared and discussed in context with two other Northern Hemisphere spring seasons, namely those in 1997 and 2011, which also displayed relatively low total ozone column values. However, during these years, total ozone columns below 220 DU over several consecutive days were not observed in spring. The similarities and differences of the atmospheric conditions of these three events and possible explanations for the observed features are presented and discussed. It becomes apparent that the monthly mean of the minimum total ozone column value for March 2020 (221 DU) was clearly below the respective values found in March 1997 (267 DU) and 2011 (252 DU), which highlights the special evolution of the polar stratospheric ozone layer in the Northern Hemisphere in spring 2020. A comparison with a typical ozone hole over the Antarctic (e.g., in 2016) indicates that although the Arctic spring 2020 situation is remarkable, with total ozone column values around or below 220 DU observed over a considerable area (up to 0.9 million km2), the Antarctic ozone hole shows total ozone columns typically below 150 DU over a much larger area (of the order of 20 million km2). Furthermore, total ozone columns below 220 DU are typically observed over the Antarctic for about 4 months.


2014 ◽  
Vol 14 (20) ◽  
pp. 28203-28230 ◽  
Author(s):  
J. Kuttippurath ◽  
S. Godin-Beekmann ◽  
F. Lefèvre ◽  
M. L. Santee ◽  
L. Froidevaux ◽  
...  

Abstract. A detailed analysis of the polar ozone loss processes during ten recent Antarctic winters is presented with high resolution Mimosa-Chim model simulations and high frequency polar vortex observations from the Aura Microwave Limb Sounder (MLS) instrument. Our model results for the Antarctic winters 2004–2013 show that chemical ozone loss starts in the edge region of the vortex at equivalent latitudes (EqLs) of 65–69° S in mid-June/July. The loss progresses with time at higher EqLs and intensifies during August–September over the range 400–600 K. The loss peaks in late September/early October, where all EqLs (65–83°) show similar loss and the maximum loss (>2 ppmv [parts per million by volume]) is found over a broad vertical range of 475–550 K. In the lower stratosphere, most winters show similar ozone loss and production rates. In general, at 500 K, the loss rates are about 2–3 ppbv sh−1 (parts per billion by volume/sunlit hour) in July and 4–5 ppbv sh−1 in August/mid-September, while they drop rapidly to zero by late September. In the middle stratosphere, the loss rates are about 3–5 ppbv sh−1 in July–August and October at 675 K. It is found that the Antarctic ozone hole (June–September) is controlled by the halogen cycles at about 90–95% (ClO–ClO, BrO–ClO, and ClO–O) and the loss above 700 K is dominated by the NOx cycle at about 70–75%. On average, the Mimosa-Chim simulations show that the very cold winters of 2005 and 2006 exhibit a maximum loss of ~3.5 ppmv around 550 K or about 149–173 DU over 350–850 K and the warmer winters of 2004, 2010, and 2012 show a loss of ~2.6 ppmv around 475–500 K or 131–154 DU over 350–850 K. The winters of 2007, 2008, and 2011 were moderately cold and thus both ozone loss and peak loss altitudes are between these two ranges (3 ppmv around 500 K or 150 ± 10 DU). The modeled ozone loss values are in reasonably good agreement with those estimated from Aura MLS measurements, but the model underestimates the observed ClO, largely due to the slower vertical descent in the model during spring.


Sign in / Sign up

Export Citation Format

Share Document