Influences of the Antarctic Ozone Hole on Southern Hemispheric Summer Climate Change

Abstract

Over the past three decades, Antarctic surface climate has undergone pronounced changes. Many of these changes have been linked to stratospheric ozone depletion. Here linkages between Antarctic ozone loss, the accompanying circulation changes, and summertime Southern Hemisphere (SH) midlatitude surface temperatures are explored. Long-term surface climate changes associated with ozone-driven changes in the southern annular mode (SAM) at SH midlatitudes in summer are not annular in appearance owing to differences in regional circulation and precipitation impacts. Both station and reanalysis data indicate a trend toward cooler summer temperatures over southeast and south-central Australia and inland areas of the southern tip of Africa. It is also found that since the onset of the ozone hole, there have been significant shifts in the distributions of both the seasonal mean and daily maximum summertime temperatures in the SH midlatitude regions between high and low ozone years. Unusually hot summer extremes are associated with anomalously high ozone in the previous November, including the recent very hot austral summer of 2012/13. If the relationship found in the past three decades continues to hold, the level of late springtime ozone over Antarctica has the potential to be part of a useful predictor set for the following summer's conditions. The results herein suggest that skillful predictions may be feasible for both the mean seasonal temperature and the frequency of extreme hot events in some SH midlatitude regions of Australia, Africa, and South America.

The Signature of Ozone Depletion in Recent Antarctic Precipitation Change: A Study With the Community Earth System Model

“…Second, because austral spring ozone depletion leads a substantial portion of the austral summer tropospheric circulation response (e.g., Bandoro et al, ), reasonable WACCM‐simulated spring ozone depletion (Marsh et al, ) lends confidence to our quantification of summer ozone‐forced precipitation change. However, we highlight that austral summer WACCM ozone recovery subsequently lags observed ozone recovery by 1–2 months, stemming from delayed breakup of the polar vortex (Marsh et al, ).…”

Simulation of polar ozone depletion: An update

“…Prior to calculation of the tendencies, the zonal mean daily values were smoothed to remove higher frequency variability. This was done by applying a 15 day low‐pass filter (a second‐order Butterworth analog filter) to the time series [see Bandoro et al ., , and references therein]. Figure shows that in the latitude band 65–75°S at this illustrative pressure level, the reference model matches the observed rate of change of HCl remarkably well, while the LIQUIDS#2 case falls below the observations, especially later in the ozone depletion season.…”

Radiative Impacts of the 2011 Abrupt Drops in Water Vapor and Ozone in the Tropical Tropopause Layer

“…Pearson correlation coefficients (R) between these time series are determined by first detrending the data. A null hypothesis that each correlation is significantly different from zero is tested with a two-sided Student's t test using an effective number of degrees of freedom accounting for the lag-1 autocorrelations of each individual time series (e.g., Bretherton et al 1999;Santer et al 2000;Bandoro et al 2014). Correlation coefficients corresponding to these tropical time series (208S-208N, 2005-13) at each vertical level are shown in Fig.…”