Influences of ozone depletion, the solar cycle and the QBO on the Southern Annular Mode

2007 ◽  
Vol 133 (628) ◽  
pp. 1855-1864 ◽  
Author(s):  
Howard K. Roscoe ◽  
Joanna D. Haigh
Keyword(s):  
Solar Cycle ◽  
Ozone Depletion ◽  
Southern Annular Mode ◽  
Annular Mode

scholarly journals Decadal Changes of Wind Stress over the Southern Ocean Associated with Antarctic Ozone Depletion

2007 ◽  
Vol 20 (14) ◽  
pp. 3395-3410 ◽  
Author(s):  
Xiao-Yi Yang ◽  
Rui Xin Huang ◽  
Dong Xiao Wang
Keyword(s):  
Southern Ocean ◽  
Wind Stress ◽  
Zonal Wind ◽  
Ozone Depletion ◽  
Surface Wind ◽  
Southern Annular Mode ◽  
Mean Flow ◽  
Annular Mode ◽  
Surface Wind Stress ◽  
Antarctic Ozone

Abstract Using 40-yr ECMWF Re-Analysis (ERA-40) data and in situ observations, the positive trend of Southern Ocean surface wind stress during two recent decades is detected, and its close linkage with spring Antarctic ozone depletion is established. The spring Antarctic ozone depletion affects the Southern Hemisphere lower-stratospheric circulation in late spring/early summer. The positive feedback involves the strengthening and cooling of the polar vortex, the enhancement of meridional temperature gradients and the meridional and vertical potential vorticity gradients, the acceleration of the circumpolar westerlies, and the reduction of the upward wave flux. This feedback loop, together with the ozone-related photochemical interaction, leads to the upward tendency of lower-stratospheric zonal wind in austral summer. In addition, the stratosphere–troposphere coupling, facilitated by ozone-related dynamics and the Southern Annular Mode, cooperates to relay the zonal wind anomalies to the upper troposphere. The wave–mean flow interaction and the meridional circulation work together in the form of the Southern Annular Mode, which transfers anomalous wind signals downward to the surface, triggering a striking strengthening of surface wind stress over the Southern Ocean.

The effect of ozone depletion on the Southern Annular Mode and stratosphere-troposphere coupling

2015 ◽  
Vol 120 (13) ◽  
pp. 6305-6312 ◽  
Author(s):  
Fraser W. Dennison ◽  
Adrian J. McDonald ◽  
Olaf Morgenstern
Keyword(s):  
Ozone Depletion ◽  
Southern Annular Mode ◽  
Annular Mode

The Southern Annular Mode in CMIP6 simulations

2021 ◽  
Author(s):  
Olaf Morgenstern
Keyword(s):  
Regression Analysis ◽  
Greenhouse Gases ◽  
Greenhouse Gas ◽  
Ozone Depletion ◽  
Climate Models ◽  
Stratospheric Ozone ◽  
Southern Annular Mode ◽  
Annular Mode ◽  
Incorrect Result ◽  
Leading Mode

<p>Stratospheric ozone depletion, along with increases in long-lived greenhouse gases, is well known to cause a strengthening of the Southern Annular Mode (SAM), the leading mode of variability in the Southern Hemisphere.  I here analyze simulations contributed to CMIP6 for signatures of these two leading drivers of climate change. For the period 1957-2014, seasonally large disagreements are found between four observational references; CMIP6-derived trends are in agreement with two out of four commonly used references. Using a regression analysis applied to model simulations with and without interactive ozone chemistry, a strengthening of the SAM in summer is attributed nearly completely to ozone depletion because a further strengthening influence due to long-lived greenhouse gases is almost fully counterbalanced by a weakening influence due to stratospheric ozone increases associated with these greenhouse gas increases. Ignoring such ozone feedbacks (an approach commonly used with no-chemistry climate models) would yield comparable contributions from these two influences, an incorrect result. In winter, trends are smaller but an influence of greenhouse gas-mediated ozone feedbacks is also identified. The regression analysis furthermore yields significant differences in the attribution of SAM changes to the two influences between models with and without interactive ozone chemistry, with ozone depletion and GHG increases playing seasonally a stronger and weaker, respectively, role in the chemistry models versus the no-chemistry ones. The results suggest that adequately representing stratospheric ozone feedbacks in climate models is critical for a correct attribution of trends in the SAM.</p>

scholarly journals Evolution of the eastward shift in the quasi-stationary minimum of the Antarctic total ozone column

2016 ◽  
Author(s):  
Asen Grytsai ◽  
Gennadi Milinevsky ◽  
Andrew Klekociuk ◽  
Oleksandr Evtushevsky
Keyword(s):  
Ozone Depletion ◽  
Total Ozone ◽  
Regional Climate ◽  
Southern Annular Mode ◽  
Reanalysis Data ◽  
Austral Spring ◽  
Annular Mode ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
Ozone Column

Abstract. The quasi-stationary pattern of the Antarctic total ozone has changed during the last four decades, demonstrating an eastward shift in the zonal ozone minimum. In this work, the association between the longitudinal shift of the zonal ozone minimum and changes in meteorological fields in austral spring (September–November) for 1979–2014 is analyzed. Regressive, correlative and anomaly composite analyses are applied to reanalysis data. Patterns of the Southern Annular Mode and quasi-stationary zonal waves 1 and 3 in the meteorological fields show relationships with interannual variability in the longitude of the zonal ozone minimum. On decadal time scales, consistent longitudinal shifts of the zonal ozone minimum and zonal wave 3 pattern in the middle troposphere temperature at the southern mid-latitudes are shown. As known, Antarctic ozone depletion in spring is strongly projected on the Southern Annular Mode in summer and impacts tropospheric climate. The results of this study suggest that changes in zonal ozone asymmetry accompanying the ozone depletion could be associated with regional climate changes in the Southern Hemisphere in spring.

scholarly journals Evolution of the eastward shift in the quasi-stationary minimum of the Antarctic total ozone column

2017 ◽  
Vol 17 (3) ◽  
pp. 1741-1758 ◽  
Author(s):  
Asen Grytsai ◽  
Andrew Klekociuk ◽  
Gennadi Milinevsky ◽  
Oleksandr Evtushevsky ◽  
Kane Stone
Keyword(s):  
Southern Hemisphere ◽  
Ozone Depletion ◽  
Total Ozone ◽  
Regional Climate ◽  
Southern Annular Mode ◽  
Reanalysis Data ◽  
Austral Spring ◽  
Annular Mode ◽  
Ozone Depleting Substances ◽  
The Antarctic

Abstract. The quasi-stationary pattern of the Antarctic total ozone has changed during the last 4 decades, showing an eastward shift in the zonal ozone minimum. In this work, the association between the longitudinal shift of the zonal ozone minimum and changes in meteorological fields in austral spring (September–November) for 1979–2014 is analyzed using ERA-Interim and NCEP–NCAR reanalyses. Regressive, correlative and anomaly composite analyses are applied to reanalysis data. Patterns of the Southern Annular Mode and quasi-stationary zonal waves 1 and 3 in the meteorological fields show relationships with interannual variability in the longitude of the zonal ozone minimum. On decadal timescales, consistent longitudinal shifts of the zonal ozone minimum and zonal wave 3 pattern in the middle-troposphere temperature at the southern midlatitudes are shown. Attribution runs of the chemistry–climate version of the Australian Community Climate and Earth System Simulator (ACCESS-CCM) model suggest that long-term shifts of the zonal ozone minimum are separately contributed by changes in ozone-depleting substances and greenhouse gases. As is known, Antarctic ozone depletion in spring is strongly projected on the Southern Annular Mode in summer and impacts summertime surface climate across the Southern Hemisphere. The results of this study suggest that changes in zonal ozone asymmetry accompanying ozone depletion could be associated with regional climate changes in the Southern Hemisphere in spring.

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