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The factors responsible for the size of Antarctic ozone hole in November are analyzed. Comparing two samples of anomalously large and small November ozone hole with respect to 1980–2017 climatology in November, the results show that the anomalously large ozone hole in austral late winter is not a precondition for the anomalously large ozone hole in November. The size of Antarctic ozone hole in November is mainly influenced by dynamical processes from the end of October to mid-November. During large November ozone hole events, weaker dynamical ozone transport appears from the end of October to mid-November, which is closely related to planetary wave divergence in the stratosphere between 60°S and 90°S. Further analyses indicate that the wave divergence is partially attributed to less upward propagation of planetary waves from the troposphere, which is associated with weak baroclinic disturbances at the end of October. Subsequently, zonal wind speed in the upper stratosphere intensifies, and the distance between critical layer (U=0) and wave reflecting surfaces becomes larger. As a result, more planetary waves are reflected and then wave divergence enhances. The processes responsible for the anomalously small Antarctic ozone holes in November are almost opposite to those for the anomalously large Antarctic ozone holes.

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 in this study. We find that the stratospheric planetary wave activities in September have weakened significantly since the year 2000, which is mainly related to the weakening of the tropospheric wave sources in the extratropical Southern Hemisphere. As the Antarctic ozone also shows clear shift around the year 2000, the impact of ozone recovery on Antarctic planetary wave activity is also examined through numerical simulations. Significant ozone recovery in the lower stratosphere changes the atmospheric state for wave propagation to some extent, inducing a slight decrease in the vertical wave flux in upper troposphere and lower stratosphere (UTLS). However, the changes in the wave propagation environment in the middle and upper stratosphere over the subpolar region are not significant. The ozone recovery has a minor contribution to the significant weakening of stratospheric planetary wave activity in September. Further analysis indicates that the trend of September sea surface temperature (SST) over 20∘ N–70∘ S is well linked to the weakening of stratospheric planetary wave activities. The model simulations reveal that the SST trend in the extratropical Southern Hemisphere (20–70∘ S) and the tropics (20–20∘ S) induce a weakening of the wave 1 component of tropospheric geopotential height in the extratropical Southern Hemisphere, which subsequently leads to a decrease in stratospheric wave flux. In addition, both reanalysis data and numerical simulations indicate that the Brewer–Dobson circulation (BDC) related to wave activities in the stratosphere has also been weakening in early austral spring since the year 2000 due to the trend of September SST in the tropics and extratropical Southern Hemisphere.

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Vitrification has attracted much attention as an efficient method for solidifying heavy metals in hazardous solid wastes, but its effect is limited when hazardous solid wastes contain chlorides. Aiming at fly ash, a normal chlorine-containing solid waste, a novel process of chlorination melting and glass curing was developed to completely realize the harmlessness of heavy metals. Melting temperature, time, and auxiliary agent were adequate to realize the harmlessness, and their influence on the migration and transformation of Cl, Na, Pb, and Zn and the leaching of slag were studied. The results showed that the majority of Cl, Na, Pb, and Zn in the fly ash had been transferred to the soot, and the residual part in the slag had been solidified in glass by controlling the process conditions. Under the optimized conditions (12 wt.% CaO and 5 wt.% SiO2 was added, the N2 flow ratio was at 1 L/min, and the melting temperature was 1300 °C for 2 h), the leaching index was determined, including the acid dissolution ratio, the Pb and Zn content of the water leaching solution, and the acid leaching solution, which all met the requirements of the relevant standards. Furthermore, the novel process provided a simple and efficient approach for the disposal of other similar solid wastes containing chlorides and heavy metals.