A pause in Southern Hemisphere circulation trends due to the Montreal Protocol

  title={A pause in Southern Hemisphere circulation trends due to the Montreal Protocol},
  author={Antara A. Banerjee and John C. Fyfe and Lorenzo M. Polvani and Darryn W. Waugh and Kai‐Lan Chang},
Observations show robust near-surface trends in Southern Hemisphere tropospheric circulation towards the end of the twentieth century, including a poleward shift in the mid-latitude jet 1 , 2 , a positive trend in the Southern Annular Mode 1 , 3 – 6 and an expansion of the Hadley cell 7 , 8 . It has been established that these trends were driven by ozone depletion in the Antarctic stratosphere due to emissions of ozone-depleting substances 9 – 11 . Here we show that these widely reported… 
Emergence of Southern Hemisphere stratospheric circulation changes in response to ozone recovery
Depletion of stratospheric ozone in the Southern Hemisphere (SH) during the late twentieth century cooled local air temperature, which resulted in stronger stratospheric westerly winds near 60° S and
Contrasting Recent Trends in Southern Hemisphere Westerlies Across Different Ocean Basins
Many studies have documented the trends in the latitudinal position and strength of the midlatitude westerlies in the Southern Hemisphere. However, very little attention has been paid to the
Influence of Ozone Forcing on 21st Century Southern Hemisphere Surface Westerlies in CMIP6 Models
The tropospheric westerly jet is a key feature of Southern Hemisphere climate. In recent decades the jet strengthened in austral summer (December–February [DJF]) and moved poleward owing to the
Is our dynamical understanding of the circulation changes associated with the Antarctic ozone hole sensitive to the choice of reanalysis dataset?
Abstract. This study quantifies differences among four widely used atmospheric reanalysis datasets (ERA5, JRA-55, MERRA-2, and CFSR) in their representation of the dynamical changes induced by
Multi-decadal surface ozone trends at globally distributed remote locations
Extracting globally representative trend information from lower tropospheric ozone observations is extremely difficult due to the highly variable distribution and interannual variability of ozone,
Twenty-first century Southern Hemisphere impacts of ozone recovery and climate change from the stratosphere to the ocean
Abstract. Changes in stratospheric ozone concentrations and increasing concentrations of greenhouse gases (GHGs) alter the temperature structure of the atmosphere and drive changes in the atmospheric
Interannual SAM Modulation of Antarctic Sea Ice Extent Does Not Account for Its Long‐Term Trends, Pointing to a Limited Role for Ozone Depletion
The expansion of Antarctic sea ice since 1979 in the presence of increasing greenhouse gases remains one of the most puzzling features of current climate change. Some studies have proposed that the
The Role of Coupled Feedbacks in the Decadal Variability of the Southern Hemisphere Eddy‐Driven Jet
Recent work has suggested that tropical Pacific decadal variability and external forcings have had a comparable influence on the observed changes in the Southern Hemisphere summertime eddy‐driven jet
Stratospheric drivers of extreme events at the Earth’s surface
The stratosphere, the layer of the atmosphere at heights between 10-50 km, is an important source of variability for the weather and climate at the Earth’s surface on timescales of weeks to decades.
Weakening of Antarctic Stratospheric Planetary Wave Activities in Early Austral Spring Since the Early 2000s: A Response to Sea Surface Temperature Trends
Abstract. Using multiple reanalysis datasets and modeling simulations, the trends of Antarctic stratospheric planetary wave activities in early austral spring since the early 2000s are investigated


Separating the Dynamical Effects of Climate Change and Ozone Depletion. Part II: Southern Hemisphere Troposphere
Abstract The separate effects of ozone depleting substances (ODSs) and greenhouse gases (GHGs) on forcing circulation changes in the Southern Hemisphere extratropical troposphere are investigated
Large cancellation, due to ozone recovery, of future Southern Hemisphere atmospheric circulation trends
The role of stratospheric ozone recovery in the Southern Hemisphere climate system, in the coming decades, is examined by contrasting two 10‐member ensembles of Community Atmospheric Model (CAM3)
Drivers of the Recent Tropical Expansion in the Southern Hemisphere: Changing SSTs or Ozone Depletion?
AbstractObservational evidence indicates that the southern edge of the Hadley cell (HC) has shifted southward during austral summer in recent decades. However, there is no consensus on the cause of
Trends in the Southern Annular Mode from Observations and Reanalyses
Several papers have described a significant trend toward the positive phase of the Southern Hemisphere annular mode (SAM) in recent decades. The SAM is the dominant mode of atmospheric variability in
Contributions of external forcings to Southern Annular Mode trends
Abstract An observed trend in the Southern Hemisphere annular mode (SAM) during recent decades has involved an intensification of the polar vortex. The source of this trend is a matter of scientific
Delayed Southern Hemisphere Climate Change Induced by Stratospheric Ozone Recovery, as Projected by the CMIP5 Models
Stratospheric ozone is expected to recover by the end of this century because of the regulation of ozonedepleting substances by the Montreal Protocol. Targeted modeling studies have suggested that
Stratospheric Ozone Depletion: The Main Driver of Twentieth-Century Atmospheric Circulation Changes in the Southern Hemisphere
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
Interpretation of Recent Southern Hemisphere Climate Change
Evidence is presented that recent trends in the SH tropospheric circulation can be interpreted as a bias toward the high-index polarity of this pattern, with stronger westerly flow encircling the polar cap.
The Impact of Stratospheric Ozone Recovery on the Southern Hemisphere Westerly Jet
Owing to the expected disappearance of the ozone hole in the first half of the 21st century, the CCMVal models predict that the tropospheric westerlies in Southern Hemisphere summer will be decelerated, on the poleward side, in contrast with the prediction of most IPCC/AR4 models.
Quantifying the Summertime Response of the Austral Jet Stream and Hadley Cell to Stratospheric Ozone and Greenhouse Gases
AbstractThe impact of anthropogenic forcing on the summertime austral circulation is assessed across three climate model datasets: the Chemistry–Climate Model Validation activity 2 and phases 3 and 5