scholarly journals The influence of large amplitude planetary waves on the Antarctic ozone hole of austral spring 2017

2019 ◽  
Vol 69 (1) ◽  
pp. 57
Author(s):  
Oleksandr Evtushevsky ◽  
Andrew R. Klekociuk ◽  
Volodymyr Kravchenko ◽  
Gennadi Milinevsky ◽  
Asen Grytsai
Keyword(s):  
Large Amplitude ◽  
Polar Vortex ◽  
Maximum Size ◽  
Planetary Waves ◽  
Ozone Hole ◽  
Late Winter ◽  
Austral Spring ◽  
Stratospheric Polar Vortex ◽  
Key Factor ◽  
The Antarctic

Quasi-stationary planetary wave activity in the lower Antarctic stratosphere in the late austral winter was an important contributor to the preconditioning of the ozone hole in spring 2017. Observations show that the ozone hole area (OHA) in spring 2017 was at the level of 1980s, that is, almost half the maximum size in 2000s. The observed OHA was close to that forecasted based on a least-squares linear regression between wave amplitude in August and OHA in September–November. We show that the key factor which contributed to the preconditioning of the Antarctic stratosphere for a relatively small ozone hole in the spring of 2017 was the development of large-amplitude stratospheric planetary waves of zonal wave numbers 1 and 2 in late winter. The waves likely originated from tropospheric wave trains and promoted the development of strong mid-latitude anticyclones in the lower stratosphere which interacted with the stratospheric polar vortex and strongly eroded the vortex in August and September, mitigating the overall level of ozone loss.

scholarly journals Anomalous quasi-stationary planetary waves over the Antarctic region in 1988 and 2002

2008 ◽  
Vol 26 (5) ◽  
pp. 1101-1108 ◽  
Author(s):  
A. V. Grytsai ◽  
O. M. Evtushevsky ◽  
G. P. Milinevsky
Keyword(s):  
Lower Stratosphere ◽  
Polar Vortex ◽  
Amplitude Distribution ◽  
Stationary Wave ◽  
Planetary Waves ◽  
Late Winter ◽  
Stratospheric Polar Vortex ◽  
Latitudinal Position ◽  
The Antarctic ◽  
Peak Value

Abstract. Anomalies in the Antarctic total ozone and amplitudes of the quasi-stationary planetary waves in the lower stratosphere temperature during the winter and spring of 1988 and 2002 have been compared. Westward displacement of the quasi-stationary wave (QSW) extremes by 50°–70° relative to the preceding years of the strong stratospheric polar vortex in 1987 and 2001, respectively, was observed. A dependence of the quasi-stationary wave ridge and trough positions on the strength of the westerly zonal wind in the lower stratosphere is shown. Comparison of the QSW amplitude in the lower stratosphere temperature in July and August shows that the amplitude distribution with latitude in August could be considered as a possible indication of the future anomalous warming in Antarctic spring. In August 2002, the QSW amplitude of 10 K at the edge region of the polar vortex (60° S–65° S) preceded the major warming in September, whereas in August 1988, the highest 7 K amplitude at 55° S preceded the large warming in the next months. These results suggest that the peak value of the lower stratosphere temperature QSW amplitude and the peak latitudinal position in late winter can influence the southern polar vortex strength in spring.

The Life Cycle and Variability of Antarctic Weak Polar Vortex Events

2022 ◽  
pp. 1-63
Keyword(s):  
Life Cycle ◽  
Polar Vortex ◽  
Southern Annular Mode ◽  
Austral Spring ◽  
Stratospheric Polar Vortex ◽  
Temperature And Precipitation ◽  
Scale Temperature ◽  
Precipitation Anomalies ◽  
Polar Stratosphere ◽  
The Antarctic

Abstract Motivated by the strong Antarctic sudden stratospheric warming (SSW) in 2019, a survey on the similar Antarctic weak polar events (WPV) is presented, including their life cycle, dynamics, seasonality, and climatic impacts. The Antarctic WPVs have a frequency of about four events per decade, with the 2002 event being the only major SSW. They show a similar life cycle to the SSWs in the Northern Hemisphere but have a longer duration. They are primarily driven by enhanced upward-propagating wavenumber 1 in the presence of a preconditioned polar stratosphere, i.e., a weaker and more contracted Antarctic stratospheric polar vortex. Antarctic WPVs occur mainly in the austral spring. Their early occurrence is preceded by an easterly anomaly in the middle and upper equatorial stratosphere besides the preconditioned polar stratosphere. The Antarctic WPVs increase the ozone concentration in the polar region and are associated with an advanced seasonal transition of the stratospheric polar vortex by about one week. Their frequency doubles after 2000 and is closely related to the advanced Antarctic stratospheric final warming in recent decades. The WPV-resultant negative phase of the southern annular mode descends to the troposphere and persists for about three months, leading to persistent hemispheric scale temperature and precipitation anomalies.

Analysis of the Antarctic Ozone Hole in November

2021 ◽  
pp. 1-53
Author(s):  
ZHE WANG ◽  
JIANKAI ZHANG ◽  
TAO WANG ◽  
WUHU FENG ◽  
YIHANG HU ◽  
...  
Keyword(s):  
Planetary Waves ◽  
Ozone Hole ◽  
Late Winter ◽  
Two Samples ◽  
Antarctic Ozone ◽  
Ozone Transport ◽  
Reflecting Surfaces ◽  
The Antarctic ◽  
Wave Divergence ◽  
Antarctic Ozone Hole

AbstractThe factors responsible for the size of Antarctic ozone hole in November are analyzed. Comparing two samples of anomalously large and small November ozone hole with respect to 1980–2017 climatology in November, the results show that the anomalously large ozone hole in austral late winter is not a precondition for the anomalously large ozone hole in November. The size of Antarctic ozone hole in November is mainly influenced by dynamical processes from the end of October to mid-November. During large November ozone hole events, weaker dynamical ozone transport appears from the end of October to mid-November, which is closely related to planetary wave divergence in the stratosphere between 60°S and 90°S. Further analyses indicate that the wave divergence is partially attributed to less upward propagation of planetary waves from the troposphere, which is associated with weak baroclinic disturbances at the end of October. Subsequently, zonal wind speed in the upper stratosphere intensifies, and the distance between critical layer (U=0) and wave reflecting surfaces becomes larger. As a result, more planetary waves are reflected and then wave divergence enhances. The processes responsible for the anomalously small Antarctic ozone holes in November are almost opposite to those for the anomalously large Antarctic ozone holes.

scholarly journals Skillful Seasonal Prediction of the Southern Annular Mode and Antarctic Ozone

2014 ◽  
Vol 27 (19) ◽  
pp. 7462-7474 ◽  
Author(s):  
William J. M. Seviour ◽  
Steven C. Hardiman ◽  
Lesley J. Gray ◽  
Neal Butchart ◽  
Craig MacLachlan ◽  
...  
Keyword(s):  
Polar Vortex ◽  
Seasonal Prediction ◽  
Southern Annular Mode ◽  
Significant Advance ◽  
Seasonal Forecasts ◽  
Austral Spring ◽  
Stratospheric Polar Vortex ◽  
Annular Mode ◽  
The North ◽  
The Antarctic

Abstract Using a set of seasonal hindcast simulations produced by the Met Office Global Seasonal Forecast System, version 5 (GloSea5), significant predictability of the southern annular mode (SAM) is demonstrated during the austral spring. The correlation of the September–November mean SAM with observed values is 0.64, which is statistically significant at the 95% confidence level [confidence interval: (0.18, 0.92)], and is similar to that found recently for the North Atlantic Oscillation in the same system. Significant skill is also found in the prediction of the strength of the Antarctic stratospheric polar vortex at 1 month average lead times. Because of the observed strong correlation between interannual variability in the strength of the Antarctic stratospheric circulation and ozone concentrations, it is possible to make skillful predictions of Antarctic column ozone amounts. By studying the variation of forecast skill with time and height, it is shown that skillful predictions of the SAM are significantly influenced by stratospheric anomalies that descend with time and are coupled with the troposphere. This effect allows skillful statistical forecasts of the October mean SAM to be produced based only on midstratosphere anomalies on 1 August. Together, these results both demonstrate a significant advance in the skill of seasonal forecasts of the Southern Hemisphere and highlight the importance of accurate modeling and observation of the stratosphere in producing long-range forecasts.

scholarly journals Is our dynamical understanding of the circulation changes associated with the Antarctic ozone hole sensitive to the choice of reanalysis dataset?

2020 ◽  
Author(s):  
Andrew Orr ◽  
Hua Lu ◽  
Patrick Martineau ◽  
Ed P. Gerber ◽  
Gareth Marshall ◽  
...  
Keyword(s):  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Polar Front ◽  
Ozone Hole ◽  
The Other ◽  
Austral Spring ◽  
Reanalysis Dataset ◽  
Stratospheric Polar Vortex ◽  
Wave Forcing ◽  
Westerly Jet

Abstract. This study quantifies differences among four widely used atmospheric reanalysis datasets (ERA5, JRA-55, MERRA-2, and CSFR) in their representation of the dynamical changes induced by severe springtime polar stratospheric ozone depletion in the Southern Hemisphere during 1980–2001. The intercomparison is undertaken as part of the SPARC (Stratosphere–troposphere Processes and their Role in Climate) Reanalysis Intercomparison Project (S-RIP). The dynamical changes associated with the ozone hole are examined by investigating the eddy heat and momentum fluxes and wave forcing. The reanalyses are generally in good agreement in their representation of the expected strengthening of the lower stratospheric polar vortex during the austral spring-summer season, as well as the descent of anomalously strong winds to the surface during summer and the subsequent poleward displacement and intensification of the polar front jet. Differences in the trends in zonal wind are generally small compared to the mean trends. The exception is CSFR, which shows greater disagreement compared to the other three reanalysis datasets, with stronger westerly winds in the lower stratosphere in spring and a larger poleward displacement of the tropospheric westerly jet in summer. Although our results suggest a high degree of consistency across the four reanalysis datasets in the representation of the dynamical changes associated with the ozone hole, there are larger differences in the wave forcing and eddy propagation changes compared to the similarities in the circulation trends. There is a large amount of disagreement in CFSR wave forcing/propagation trends compared to the other three reanalyses, while the best agreement is found between ERA5 and JRA-55. The underlying causes of these differences are consistent with the wind response being more constrained by the assimilation of observations compared to the wave forcing, which is more dependent on the model-based forecasts that can differ between reanalyses. Looking forward, these findings give us confidence that reanalysis datasets can be used to assess changes associated with the ongoing recovery of stratospheric ozone.

scholarly journals Ground-Based DOAS Measurements of Stratospheric Trace Gases at Two Antarctic Stations during the 2002 Ozone Hole Period

2005 ◽  
Vol 62 (3) ◽  
pp. 765-777 ◽  
Author(s):  
U. Frieß ◽  
K. Kreher ◽  
P. V. Johnston ◽  
U. Platt
Keyword(s):  
Trace Gases ◽  
Wavelength Region ◽  
Polar Vortex ◽  
Early Spring ◽  
Ozone Hole ◽  
Optical Absorption Spectroscopy ◽  
Austral Spring ◽  
Small Vortex ◽  
The Antarctic ◽  
Stratospheric Trace Gases

Abstract Compared to recent years, the development of the Antarctic ozone hole in 2002 showed very unusual dynamical features. The midwinter polar vortex was one of the smallest observed during the past decade. Driven by planetary waves, the vortex showed a strong asymmetry in early spring. A large air mass separated in late September, leaving what was previously a small vortex even smaller. Furthermore, stratospheric temperatures exceeded the polar stratospheric cloud (PSC) threshold earlier than in previous years, leading to a decrease in halogen activation by heterogeneous surface reactions. Ground-based observation of stratospheric trace gases in austral spring of 2001 and 2002 using passive Differential Optical Absorption Spectroscopy (DOAS) observations of zenith-scattered sunlight in the UV and visible wavelength region (320–650 nm) are presented. Using DOAS measurements of ozone, NO2, BrO, and OClO at two different Antarctic sites, Neumayer Station (70°S, 8°W) and Arrival Heights (78°S, 167°E), the chemical composition of the stratosphere is investigated under the unusual conditions of the 2002 ozone hole period and compared to the more typical observations of the previous year (2001).

Longitudinal peculiarities of planetary waves-zonal flow interaction and its role in stratosphere-troposphere dynamical coupling

2021 ◽  
Author(s):  
Wei Ke ◽  
Wen Chen ◽  
Pavel Vargin
Keyword(s):  
Wave Train ◽  
Polar Vortex ◽  
Planetary Waves ◽  
Northern Eurasia ◽  
Late Winter ◽  
Early Winter ◽  
Eastern United States ◽  
Stratospheric Polar Vortex ◽  
Downward Flux ◽  
Wave Flux

Abstract The three-dimensional (3D) planetary wave analysis provides more regionalized information on stratospheric-tropospheric dynamic interactions. The upward wave flux from the troposphere to the stratosphere is maximized above north-eastern Eurasia, while the downward flux is mainly over the North America and North Atlantic (NANA) region, which is much stronger in mid and late winter. This distribution is determined by the wave-wave interaction between the different wavenumbers of planetary waves, especially between wavenumber 1 and wavenumber 2. The upward wave flux anomalies in early winter are negatively correlated with the strength of the stratospheric polar vortex (SPV). In the mid and late winter months, the strength of the SPV is positively correlated with the first mode of 3D wave flux and has a leading relationship of approximately one month. The stronger SPV corresponds to a stronger upward wave flux above northern Eurasia and stronger downward flux over the NANA region. The interannual variation in wave flux in early winter is closely associated with the Scandinavian wave train pattern. In contrast, the wave flux variation is related to the circulation anomaly corresponding to Arctic Oscillation in mid and late winter, which causes climate anomalies across the Northern Hemisphere, especially coherent temperature changes in northern Europe, eastern United States and northeastern China.

scholarly journals The 2019 Southern Hemisphere stratospheric polar vortex weakening and its impacts

2021 ◽  
pp. 1-50
Author(s):  
Eun-Pa Lim ◽  
Harry H. Hendon ◽  
Amy H. Butler ◽  
David W. J. Thompson ◽  
Zachary Lawrence ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Polar Vortex ◽  
Austral Spring ◽  
Stratospheric Polar Vortex ◽  
Climate Conditions ◽  
Extreme Climate ◽  
The Antarctic

Capsule SummaryDuring austral spring 2019 the Antarctic stratosphere experienced record-breaking warming and a near-record polar vortex weakening, resulting in predictable extreme climate conditions throughout the Southern Hemisphere through December 2019.

scholarly journals A meridional structure of static stability and ozone vertical gradient around the tropopause in the Southern Hemisphere extratropics

2010 ◽  
Vol 10 (8) ◽  
pp. 19175-19194 ◽  
Author(s):  
Y. Tomikawa ◽  
T. Yamanouchi
Keyword(s):  
Southern Hemisphere ◽  
Seasonal Variations ◽  
Inversion Layer ◽  
Polar Vortex ◽  
Vertical Gradient ◽  
Static Stability ◽  
Radiative Heating ◽  
Stratospheric Polar Vortex ◽  
Close Relationship ◽  
The Antarctic

Abstract. An analysis of the static stability and ozone vertical gradient in the ozone tropopause based (OTB) coordinate is applied to the ozonesonde data at 10 stations in the Southern Hemisphere (SH) extratropics. The tropopause inversion layer (TIL) with a static stability maximum just above the tropopause shows similar seasonal variations at two Antarctic stations, which are latitudinally far from each other. Since the sunshine hour varies with time in a quite different way between these two stations, it implies that the radiative heating due to solar ultraviolet absorption of ozone does not contribute to the seasonal variation of the TIL. A meridional section of the static stability in the OTB coordinate shows that the static stability just above the tropopause has a large latitudinal gradient between 60° S and 70° S in austral winter because of the absence of the TIL over the Antarctic. It is accompanied by an increase of westerly shear with height above the tropopause, so that the polar-night jet is formed above this latitude region. This result suggests a close relationship between the absence of the TIL and the stratospheric polar vortex in the Antarctic winter. A vertical gradient of ozone mixing ratio, referred to as ozone vertical gradient, around the tropopause shows similar latitudinal and seasonal variations with the static stability in the SH extratropics. In a height region above the TIL, a small ozone vertical gradient in the midlatitudes associated with the Antarctic ozone hole is observed in a height region of the subvortex but not around the polar vortex. This is a clear evidence of active latitudinal mixing between the midlatitudes and subvortex.

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