Trends evolution of ozone between 1980 and 2000 at midlatitudes over the Southern Hemisphere: Decadal differences in trends

Abstract

The variability of atmospheric midlatitudinal ozone between 1980 and 2000 over the Southern Hemisphere is discussed. The distribution of ozone and ozone change during the seasonal cycle is discussed using Total Ozone Mapping Spectrometer Nimbus and Earth Probe data binned at 72 (30° longitude by 5° latitude) bins, between 60° and 30°S. Rather than using a standard trend approach, the annual mean time series for each bin were fitted with a cubic polynomial. The results show that in the zonal mean sense there is a sizable, latitude‐dependent slowdown of the ozone loss from the early 1990s onward, but when individual bins are considered, significant longitudinal patterns of ozone change appear, with both positive (enhancement) and negative (depletion) changes in total ozone. Thus regional evolution remains important as an indicator both of chemical depletion evolution and the relation with climate. Such longitudinal behavior is limited in the subtropics and grows toward the subpolar edge of the sampled region. For example, a large decrease was observed over southern South America in the 1980s, but during the 1990s there was only a limited change. The analysis for January, June, and October over the 20‐year period shows changes in the evolution along the year, both in time and space. Furthermore, such seasonally dependent changes reach a peak in October, as would be expected. The October pattern of interannual variability could be linked to Southern Annular Mode, though there probably are some other processes driving it.

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

“…2a and b, there appears to be some consistency in the epoch of inflexion in the tendencies of both the column amount and the maximum eastward longitude shift of the zonal TOC minimum (around 2000). The eastward shift in the QSW structure over Antarctica has been described previously (Huth and Canziani, 2003;Grytsai et al, 2005Grytsai et al, , 2007aMalanca et al, 2005;Canziani, 2010, 2011;Lin et al, 2010;Grytsai, 2011;Hassler et al, 2011). Eastward shift speeds of about 15-20 • decade −1 are consistent among various studies (Grytsai et al, 2007a;Lin et al, 2010;Hassler et al, 2011).…”

“…Previous studies have revealed the tendency of the Antarctic polar vortex to exhibit an eastward shift in orientation (Huth and Canziani, 2003), in the ozone minimum location (Grytsai et al, 2005;Malanca et al, 2005;Grytsai et al, 2007a, b;Canziani, 2010, 2011;Grytsai, 2011;Hassler et al, 2011) and in the phase of wave 1 in stratospheric temperature (Lin et al, 2010). This eastward shift has been described as possibly connected with a change in tropospheric stationary waves (Grytsai et al, 2007a), tropospheric jet structure (Hio and Hirota, 2002;Agosta and Canziani, 2011) and its strengthening (Wang et al, 2013), and stratospheric ozone and volcanic aerosol concentration (Lin et al, 2010).…”

“…The distribution of total column ozone over Antarctica is significantly non-uniform during austral spring, i.e., in September-November (Wirth, 1993;Malanca et al, 2005;Grytsai et al, 2007a;Canziani, 2010, 2011). This has particularly been the case since the early 1980s due to the presence of ozone depletion associated with the ozone hole (Chubachi, 1984;Farman et al, 1985;Chubachi and Kajiwara, 1986;Stolarski et al, 1986;Solomon, 1999).…”

Detection of Multidecadal Changes in UVB and Total Ozone Concentrations over the Continental US with NASA TOMS Data and USDA Ground-Based Measurements

“…As a prelude to a full-scale causal investigation, an advanced intercomparison between total ozone and Ultraviolet-B (UVB) at differing spatial and temporal scales across the continental USA is of value to explore any abnormal trends and unusual correlations [9][10][11]. However, TOMS data had anomalies in the year 2000 and Earth Probe TOMS began to experience two problems after 2000, including a drop in throughput of the instrument of about 50%, and a cross track bias such that ozone measured when looking to the far left of the orbit track is 2% to 3% lower than ozone measured when looking to the far right of the orbit track.…”

Increased UV radiation due to polar ozone chemical depletion and vortex occurrences at Southern Sub-polar Latitudes in the period [1997–2005]

“…The TOC outside vortex monthly climatology is computed with a resolution of 1 • ×1 • . A climatology varying with latitude and longitude was chosen in order to reflect TOC climatological changes as a function of longitude as noted in Malanca et al (2005). A monthly average is performed in order to take into account the dependence of TOC with season and to avoid the weak number of situations outside of the vortex for the higher latitudes.…”