Emergence of Southern Hemisphere circulation changes in response to ozone recovery

2020 ◽  
Author(s):  
Brian Zambri ◽  
Susan Solomon ◽  
David Thompson ◽  
Qiang Fu
Keyword(s):  
Southern Hemisphere ◽  
Ozone Depletion ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Montreal Protocol ◽  
Stratospheric Polar Vortex ◽  
Surface Climate ◽  
Antarctic Ozone ◽  
Ozone Depleting Substances ◽  
Circulation Changes

<p>Ozone depletion in the Southern Hemisphere (SH) stratosphere in the late 20<sup>th</sup> century cooled the air there, strengthening the SH stratospheric westerly winds near 60ºS and altering SH surface climate. Since ~1999, trends in Antarctic ozone have begun to recover, exhibiting a flattening followed by a sign reversal in response to decreases in stratospheric chlorine concentration due to the Montreal Protocol, an international treaty banning the production and consumption of ozone-depleting substances. Here we show that the post–1999 increase in ozone has resulted in thermal and circulation changes of opposite sign to those that resulted from stratospheric ozone losses, including a warming of the SH polar lower stratosphere and a weakening of the SH stratospheric polar vortex.  Further, these altered trends extend to the upper troposphere, albeit of smaller magnitudes.  Observed post–1999 trends of temperature and circulation in the stratosphere are about 20–25% the magnitude of those of the ozone depletion era, and are broadly consistent with expectations based on modeled depletion-era trends and variability of both ozone and reactive chlorine, thereby indicating the emergence of healing of dynamical impacts of the Antarctic ozone hole.</p>

scholarly journals The importance of interactive chemistry for stratosphere–troposphere–coupling

2018 ◽  
Author(s):  
Sabine Haase ◽  
Katja Matthes
Keyword(s):  
Ozone Depletion ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Ocean Model ◽  
Recent Past ◽  
Stratospheric Polar Vortex ◽  
Surface Climate ◽  
The Mean ◽  
Mean State

Abstract. Recent observational and modeling studies suggest that not only southern hemispheric surface climate is influenced by stratospheric ozone depletion but also northern hemisphere (NH) spring, implying a strong interaction between dynamics and chemistry. Here, we systematically analyze the importance of interactive chemistry for the representation of stratosphere–troposphere–coupling and in particular the effects on NH surface climate during the recent past. We use the interactive and specified chemistry version of NCAR's Whole Atmosphere Community Climate Model coupled to an ocean model to investigate differences in the mean state of the NH stratosphere as well as in stratospheric extreme events, namely sudden stratospheric warmings (SSWs), and their surface impacts. We also test the effects of zonally symmetric versus asymmetric prescribed ozone, testing the importance of ozone waves for the representation of stratospheric mean state and variability. The interactive chemistry simulation is characterized by a statistically significant stronger and colder polar night jet (PNJ) during spring when ozone depletion becomes important. We identify a negative feedback between lower stratospheric ozone and atmospheric dynamics during the break down of the stratospheric polar vortex in the NH, which contributes to the different characteristics of the PNJ between the simulations. Not only the mean state, but also stratospheric variability is better represented in the interactive chemistry simulation, which shows a more realistic distribution of SSWs as well as a more persisting surface impact afterwards compared to the simulation where the feedback between chemistry and dynamics is switched off. We hypothesize that this is also related to the feedback between ozone and dynamics through the intrusion of ozone rich air into polar latitudes during SSWs. The results from the zonally asymmetric ozone simulation are closer to the interactive chemistry simulations, implying that a three-dimensional representation of prescribed ozone is necessary and desirable in case interactive chemistry is not available or possible for (multi-) centennial simulations. Our findings underline the importance of the representation of interactive chemistry and its feedback on the stratospheric mean state and variability not only on the SH but also on the NH during the recent past.

scholarly journals The importance of interactive chemistry for stratosphere–troposphere coupling

2019 ◽  
Vol 19 (5) ◽  
pp. 3417-3432 ◽  
Author(s):  
Sabine Haase ◽  
Katja Matthes
Keyword(s):  
Ozone Depletion ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Ocean Model ◽  
Recent Past ◽  
Stratospheric Polar Vortex ◽  
Model Version ◽  
Surface Climate ◽  
The Mean ◽  
Mean State

Abstract. Recent observational and modeling studies suggest that stratospheric ozone depletion not only influences the surface climate in the Southern Hemisphere (SH), but also impacts Northern Hemisphere (NH) spring, which implies a strong interaction between dynamics and chemistry. Here, we systematically analyze the importance of interactive chemistry with respect to the representation of stratosphere–troposphere coupling and in particular the effects on NH surface climate during the recent past. We use the interactive and specified chemistry version of NCAR's Whole Atmosphere Community Climate Model coupled to an ocean model to investigate differences in the mean state of the NH stratosphere as well as in stratospheric extreme events, namely sudden stratospheric warmings (SSWs), and their surface impacts. To be able to focus on differences that arise from two-way interactions between chemistry and dynamics in the model, the specified chemistry model version uses a time-evolving, model-consistent ozone field generated by the interactive chemistry model version. We also test the effects of zonally symmetric versus asymmetric prescribed ozone, evaluating the importance of ozone waves in the representation of stratospheric mean state and variability. The interactive chemistry simulation is characterized by a significantly stronger and colder polar night jet (PNJ) during spring when ozone depletion becomes important. We identify a negative feedback between lower stratospheric ozone and atmospheric dynamics during the breakdown of the stratospheric polar vortex in the NH, which contributes to the different characteristics of the PNJ between the simulations. Not only the mean state, but also stratospheric variability is better represented in the interactive chemistry simulation, which shows a more realistic distribution of SSWs as well as a more persistent surface impact afterwards compared with the simulation where the feedback between chemistry and dynamics is switched off. We hypothesize that this is also related to the feedback between ozone and dynamics via the intrusion of ozone-rich air into polar latitudes during SSWs. The results from the zonally asymmetric ozone simulation are closer to the interactive chemistry simulations, implying that under a model-consistent ozone forcing, a three-dimensional (3-D) representation of the prescribed ozone field is desirable. This suggests that a 3-D ozone forcing, as recommended for the upcoming CMIP6 simulations, has the potential to improve the representation of stratospheric dynamics and chemistry. Our findings underline the importance of the representation of interactive chemistry and its feedback on the stratospheric mean state and variability not only in the SH but also in the NH during the recent past.

scholarly journals Technical note: LIMS observations of lower stratospheric ozone in the southern polar springtime of 1978

2020 ◽  
Vol 20 (6) ◽  
pp. 3663-3668
Author(s):  
Ellis Remsberg ◽  
V. Lynn Harvey ◽  
Arlin Krueger ◽  
Larry Gordley ◽  
John C. Gille ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Nitrogen Dioxide ◽  
Southern Hemisphere ◽  
Polar Region ◽  
Lower Stratosphere ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Technical Note ◽  
Stratospheric Ozone Layer ◽  
Antarctic Ozone

Abstract. The Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) instrument operated from 25 October 1978 through 28 May 1979. This note focuses on its Version 6 (V6) data and indications of ozone loss in the lower stratosphere of the Southern Hemisphere subpolar region during the last week of October 1978. We provide profiles and maps that show V6 ozone values of only 2 to 3 ppmv at 46 hPa within the edge of the polar vortex near 60∘ S from late October through mid-November 1978. There are also low values of V6 nitric acid (∼3 to 6 ppbv) and nitrogen dioxide (< 1 ppbv) at the same locations, indicating that conditions were suitable for a chemical loss of Antarctic ozone some weeks earlier. These “first light” LIMS observations provide the earliest space-based view of conditions within the lower stratospheric ozone layer of the southern polar region in springtime.

scholarly journals Robust effects of springtime Arctic ozone depletion on surface climate

2021 ◽  
Author(s):  
Marina Friedel ◽  
Gabriel Chiodo ◽  
Andrea Stenke ◽  
Daniela Domeisen ◽  
Stephan Fueglistaler ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Negative Temperature ◽  
Significant Degree ◽  
The Arctic ◽  
Surface Climate ◽  
Northern Hemispheric ◽  
The Impact

Abstract Massive spring ozone loss due to anthropogenic emissions of ozone depleting substances is not limited to the austral hemisphere, but can also occur in the Arctic. Previous studies have suggested a link between springtime Arctic ozone depletion and Northern Hemispheric surface climate, which might add surface predictability. However, so far it has not been possible to isolate the role of stratospheric ozone from dynamical downward impacts. For the first time, we quantify the impact of springtime Arctic ozone depletion on surface climate using observations and targeted chemistry-climate model experiments to isolate the effects of ozone feedbacks. We find that springtime stratospheric ozone depletion is followed by surface anomalies in precipitation and temperature resembling a positive Arctic Oscillation. Most notably, we show that these anomalies, affecting large portions of the Northern Hemisphere, cannot be explained by dynamical variability alone, but are to a significant degree driven by stratospheric ozone. The surface signal is linked to reduced shortwave absorption by stratospheric ozone, forcing persistent negative temperature anomalies in the lower stratosphere and a delayed breakup of the polar vortex - analogous to ozone-surface coupling in the Southern Hemisphere.These results suggest that Arctic stratospheric ozone actively forces springtime Northern Hemispheric surface climate and thus provides a source of predictability on seasonal scales.

scholarly journals Connection between Antarctic Ozone and Climate: Interannual Precipitation Changes in the Southern Hemisphere

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 579
Author(s):  
Alessandro Damiani ◽  
Raul R. Cordero ◽  
Pedro J. Llanillo ◽  
Sarah Feron ◽  
Juan P. Boisier ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Stratospheric Ozone ◽  
Southern Annular Mode ◽  
Early Summer ◽  
Summer Period ◽  
Surface Climate ◽  
Eastern Australia ◽  
Antarctic Ozone ◽  
Stratospheric Circulation ◽  
Precipitation Changes

In this study, we explored the connection between anomalies in springtime Antarctic ozone and all-year precipitation in the Southern Hemisphere by using observations from 1960–2018 and coupled simulations for 1960–2050. The observations showed that this correlation was enhanced during the last several decades, when a simultaneously increased coupling between ozone and Southern Annular Mode (SAM) anomalies became broader, covering most of the following summer and part of the previous winter. For eastern Australia, the ozone–precipitation connection shows a greater persistence toward the following summer than for other regions. On the other hand, for South America, the ozone–precipitation correlation seems more robust, especially in the early summer. There, the correlation also covers part of the previous winter, suggesting that winter planetary waves could affect both parameters. Further, we estimated the sensitivity of precipitation to changes in Antarctic ozone. In both observations and simulations, we found comparable sensitivity values during the spring–summer period. Overall, our results indicate that ozone anomalies can be understood as a tracer of stratospheric circulation. However, simulations indicate that stratospheric ozone chemistry still contributes to strengthening the interannual relationship between ozone and surface climate. Because simulations reproduced most of the observed connections, we suggest that including ozone variability in seasonal forecasting systems can potentially improve predictions.

scholarly journals Evolution of the stratospheric polar vortex in the Southern and Northern Hemispheres over the period 1979 – 2020

2021 ◽  
Author(s):  
Audrey Lecouffe ◽  
Sophie Godin-Beekmann ◽  
Andrea Pazmiño ◽  
Alain Hauchecorne
Keyword(s):  
Southern Hemisphere ◽  
Potential Vorticity ◽  
Southern Oscillation ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Geophysical Research ◽  
Quasi Biennial Oscillation ◽  
Stratospheric Polar Vortex ◽  
Antarctic Polar Vortex ◽  
The Antarctic

&lt;p&gt;The stratospheric polar vortex in the Southern Hemisphere plays an important role in the intensity of the stratospheric ozone destruction during austral spring, which started in the late 1970s. The so-called ozone hole has in turn influenced the evolution of weather patterns in the Southern Hemisphere in the last decades (WMO, 2018). The Northern Hemisphere polar vortex is less stable because of larger dynamical activity in winter. It is thus less cold and polar arctic ozone losses are less important. The seasonal and interannual evolution of the polar vortex in both hemispheres has been analyzed using meteorological fields from the European Center for Meteorology Weather Forecasts ERA-Interim reanalyses and the MIMOSA model (Mod&amp;#233;lisation Isentrope du transport M&amp;#233;so-&amp;#233;chelle de l&amp;#8217;Ozone Stratosph&amp;#233;rique par Advection, Hauchecorne et al., 2002). This model provides high spatial resolution potential vorticity (PV) and equivalent latitude fields at several isentropic levels (675K, 550K and 475K) that are used to evaluate the temporal evolution of the polar vortex edge. The edge of the vortex is computed on isentropic surfaces from the wind and gradient of PV as a function of equivalent latitude (e.g. Nash et al, 1996; Godin et al., 2001). On an interannual scale, the signature of some typical forcings driving stratospheric natural variability such as the 11-year solar cycle, the quasi-biennial oscillation (QBO), and El Ni&amp;#241;o Southern Oscillation (ENSO) is evaluated. The study includes analysis of the onset and breakup dates of the polar vortex, which are determined from the wind field along the vortex edge. Several threshold values, such as 15.2m/s, 20m/s and 25m/s following Akiyoshi et al. (2009) are used. Results on the seasonal and interannual evolution of the intensity and position of the vortex edge, as well as the onset and breakup dates of the Southern and Northern polar vortex edge over the 1979 &amp;#8211; 2020 period will be shown.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&lt;ul&gt;&lt;li&gt;Akiyoshi, H., Zhou, L., Yamashita, Y., Sakamoto, K., Yoshiki, M., Nagashima, T., Takahashi, M., Kurokawa, J., Takigawa, M., and Imamura, T. A CCM simulation of the breakup of the Antarctic polar vortex in the years 1980&amp;#8211;2004 under the CCMVal scenarios, Journal ofGeophysical Research: Atmospheres, 114, 2009.&lt;/li&gt; &lt;li&gt;Godin S., V. Bergeret, S. Bekki, C. David, G. Me&amp;#769;gie, Study of the interannual ozone loss and the permeability of the Antarctic Polar Vortex from long-term aerosol and ozone lidar measurements in Dumont d&amp;#8217;Urville (66.4&amp;#9702;S, 140&amp;#9702;E), J. Geophys. Res., 106, 1311-1330, 2001.&lt;/li&gt; &lt;li&gt;Hauchecorne, A., S. Godin, M. Marchand, B. Hesse, and C. Souprayen, Quantification of the transport of chemical constituents from the polar vortex to midlatitudes in the lower stratosphere using the high-resolution advection model MIMOSA and effective diffusivity, J. Geophys. Res., 107 (D20), 8289, doi:10.1029/2001JD000491, 2002.&lt;/li&gt; &lt;li&gt;Nash, E. R., Newman, P. A., Rosenfield, J. E., and Schoeberl, M. R. (1996), An objective determination of the polar vortex using Ertel&amp;#8217;s potential vorticity, Journal of geophysical research, VOL.101(D5), 9471- 9478&lt;/li&gt; &lt;li&gt;World Meteorological Organization, Global Ozone Research and Monitoring Project &amp;#8211; Report No. 58, 2018.&lt;/li&gt; &lt;/ul&gt;

scholarly journals Stratospheric Ozone Depletion: The Main Driver of Twentieth-Century Atmospheric Circulation Changes in the Southern Hemisphere

2011 ◽  
Vol 24 (3) ◽  
pp. 795-812 ◽  
Author(s):  
Lorenzo M. Polvani ◽  
Darryn W. Waugh ◽  
Gustavo J. P. Correa ◽  
Seok-Woo Son
Keyword(s):  
Twentieth Century ◽  
Greenhouse Gases ◽  
Atmospheric Circulation ◽  
Southern Hemisphere ◽  
Ozone Depletion ◽  
General Circulation ◽  
Stratospheric Ozone ◽  
Hadley Cell ◽  
Stratospheric Ozone Depletion ◽  
Circulation Changes

Abstract The importance of stratospheric ozone depletion on the atmospheric circulation of the troposphere is studied with an atmospheric general circulation model, the Community Atmospheric Model, version 3 (CAM3), for the second half of the twentieth century. In particular, the relative importance of ozone depletion is contrasted with that of increased greenhouse gases and accompanying sea surface temperature changes. By specifying ozone and greenhouse gas forcings independently, and performing long, time-slice integrations, it is shown that the impacts of ozone depletion are roughly 2–3 times larger than those associated with increased greenhouse gases, for the Southern Hemisphere tropospheric summer circulation. The formation of the ozone hole is shown to affect not only the polar tropopause and the latitudinal position of the midlatitude jet; it extends to the entire hemisphere, resulting in a broadening of the Hadley cell and a poleward extension of the subtropical dry zones. The CAM3 results are compared to and found to be in excellent agreement with those of the multimodel means of the recent Coupled Model Intercomparison Project (CMIP3) and Chemistry–Climate Model Validation (CCMVal2) simulations. This study, therefore, strongly suggests that most Southern Hemisphere tropospheric circulation changes, in austral summer over the second half of the twentieth century, have been caused by polar stratospheric ozone depletion.

scholarly journals The Importance of the Montreal Protocol in Protecting Earth’s Hydroclimate

2013 ◽  
Vol 26 (12) ◽  
pp. 4049-4068 ◽  
Author(s):  
Yutian Wu ◽  
Lorenzo M. Polvani ◽  
Richard Seager
Keyword(s):  
Ozone Depletion ◽  
Radiative Forcing ◽  
Hydrological Cycle ◽  
Stratospheric Ozone ◽  
Atmospheric Model ◽  
Ultraviolet B ◽  
Montreal Protocol ◽  
Mixed Layer Ocean ◽  
The World ◽  
Ozone Depleting Substances

Abstract The 1987 Montreal Protocol regulating emissions of chlorofluorocarbons (CFCs) and other ozone-depleting substances (ODSs) was motivated primarily by the harm to human health and ecosystems arising from increased exposure to ultraviolet-B (UV-B) radiation associated with depletion of the ozone layer. It is now known that the Montreal Protocol has helped reduce radiative forcing of the climate system since CFCs are greenhouse gases (GHGs), and that ozone depletion (which is now on the verge of reversing) has been the dominant driver of atmospheric circulation changes in the Southern Hemisphere in the last half century. This paper demonstrates that the Montreal Protocol also significantly protects Earth’s hydroclimate. Using the Community Atmospheric Model, version 3 (CAM3), coupled to a simple mixed layer ocean, it is shown that in the “world avoided” (i.e., with CFC emissions not regulated), the subtropical dry zones would be substantially drier, and the middle- and high-latitude regions considerably wetter in the coming decade (2020–29) than in a world without ozone depletion. Surprisingly, these changes are very similar, in both pattern and magnitude, to those caused by projected increases in GHG concentrations over the same period. It is further shown that, by dynamical and thermodynamical mechanisms, both the stratospheric ozone depletion and increased CFCs contribute to these changes. The results herein imply that, as a consequence of the Montreal Protocol, changes in the hydrological cycle in the coming decade will be only half as strong as what they otherwise would be.

The Role of Stratospheric Polar Vortex Breakdown in Southern Hemisphere Climate Trends

2014 ◽  
Vol 71 (7) ◽  
pp. 2335-2353 ◽  
Author(s):  
Lantao Sun ◽  
Gang Chen ◽  
Walter A. Robinson
Keyword(s):  
Southern Hemisphere ◽  
Ozone Depletion ◽  
Climate Model ◽  
Vortex Breakdown ◽  
Polar Vortex ◽  
Wave Drag ◽  
Hadley Cell ◽  
Climate Trends ◽  
Stratospheric Polar Vortex

Abstract This paper investigates the connection between the delay in the final breakdown of the stratospheric polar vortex, the stratospheric final warming (SFW), and Southern Hemisphere climate trends. The authors first analyze Interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) and three climate model outputs with different climate forcings. Climate trends appear when there is a delay in the timing of SFWs. When regressed onto the SFW dates (which reflect the anomaly when the SFW is delayed for one standard deviation of its onset dates), the anomaly pattern bears a resemblance to the observed climate trends, for all the model outputs, even without any trends. This suggests that the stratospheric and tropospheric circulations are organized by the timing of SFWs in both the interannual time scale and climate trends because of external forcings. The authors further explore the role of the SFW using a simplified dynamical model in which the ozone depletion is mimicked by a springtime polar stratospheric cooling. The responses of zonal-mean atmospheric circulation, including zonal wind, temperature, and poleward edge of the Hadley cell and the Ferrel cell, are similar to the observed climate trends. The authors divide the years into those in which the SFW is delayed and those in which it is not. The responses for the years in which the SFW is delayed are very similar to the overall response, while the stratosphere is only characterized by the localized cooling for those years in which the SFW is not delayed, with no subsequent downward influence into the troposphere. This suggests that, in order to affect the troposphere, ozone depletion must first delay the SFW so as to induce a deep response in planetary wave drag and the associated eddy-driven circulation.

scholarly journals Delayed Southern Hemisphere Climate Change Induced by Stratospheric Ozone Recovery, as Projected by the CMIP5 Models

2014 ◽  
Vol 27 (2) ◽  
pp. 852-867 ◽  
Author(s):  
Elizabeth A. Barnes ◽  
Nicholas W. Barnes ◽  
Lorenzo M. Polvani
Keyword(s):  
Climate Change ◽  
Southern Hemisphere ◽  
Ozone Depletion ◽  
Stratospheric Ozone ◽  
Ghg Emissions ◽  
Montreal Protocol ◽  
First Century ◽  
Cmip5 Models ◽  
Climate Response ◽  
Twenty First Century

Abstract Stratospheric ozone is expected to recover by the end of this century because of the regulation of ozone-depleting substances by the Montreal Protocol. Targeted modeling studies have suggested that the climate response to ozone recovery will greatly oppose the climate response to rising greenhouse gas (GHG) emissions. However, the extent of this cancellation remains unclear since only a few such studies are available. Here, a much larger set of simulations performed for phase 5 of the Coupled Model Intercomparison Project is analyzed, which includes ozone recovery. It is shown that the closing of the ozone hole will cause a delay in summertime [December–February (DJF)] Southern Hemisphere climate change between now and 2045. Specifically, it is found that the position of the jet stream, the width of the subtropical dry zones, the seasonality of surface temperatures, and sea ice concentrations all exhibit significantly reduced summertime trends over the first half of the twenty-first century as a consequence of ozone recovery. After 2045, forcing from GHG emissions begins to dominate the climate response. Finally, comparing the relative influences of future GHG emissions and historic ozone depletion, it is found that the simulated DJF tropospheric circulation changes between 1965 and 2005 (driven primarily by ozone depletion) are larger than the projected changes in any future scenario over the entire twenty-first century.

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