Emergence of ozone recovery evidenced by reduction in the occurrence of Antarctic ozone loss saturation

J Kuttippurath,P C Pandey,P J Nair,P Kumar

doi:10.1038/s41612-018-0052-6

J Kuttippurath, P C Pandey + Show 2 more

Open Access

https://doi.org/10.1038/s41612-018-0052-6

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Abstract

Industrial emissions of ozone depleting substances (ODSs) during the second half of the twentieth century have led to one of the most visible human impacts on the Earth: the Antarctic ozone hole. The ozone loss intensified in the 1980s and reached the level of saturation (i.e., complete loss of ozone) due to the high levels of ODSs in the atmosphere. Significant changes in the southern hemispheric climate have been observed in the past decades due to this unprecedented ozone loss. Although the most recent studies suggest healing in the Antarctic ozone hole, the status of ozone in the loss saturation layer (~13–21 km) has not been discussed in detail. Here, a comprehensive analysis of vertical, spatial and temporal evolution of ozone loss saturation (ozone mixing ratio ≤ 0.1 ppmv) in the Antarctic vortex using high resolution measurements for the 1979–2017 period reveals that the loss saturation began in 1987 and continued to occur in all winters thereafter, except in the major warming winters of 1988 and 2002. However, our analysis shows a clear reduction in the frequency of occurrence of ozone loss saturation over the period 2001–2017 consistently throughout various datasets (e.g., ozonesonde and satellite measurements of ozone profiles and total columns), thereby revealing the emergence of an important milestone in ozone recovery.

Highlights

The ozone loss process in the stratosphere is relatively well understood, and much of the loss is driven by the chemical cycles involving chlorine and bromine compounds, whose abundance peaked around 2000 in the polar stratosphere.[1]
One of the main difficulties in determining accurate trends in ozone in the southern polar stratosphere is the complete loss of ozone there
The ozone profiles illustrate that the complete loss of ozone begins at the altitude of about 350 K (~12 km) and vertically spreads up to 550 K (~22 km) with frequent loss saturation occurrences at 400–450 K (~13–16 km), where the total loss of ozone occurs at most stations

Summary

Introduction

The ozone loss process in the stratosphere is relatively well understood, and much of the loss is driven by the chemical cycles involving chlorine and bromine compounds, whose abundance peaked around 2000 in the polar stratosphere.[1]. We present, to our knowledge, the first detailed long-term (four decades) analysis of Antarctic ozone loss saturation in terms of its first occurrence, timing, spatial differences, vertical spread, interannual changes and temporal evolution using high-resolution ozonesondes and satellite measurements inside the vortex for the 1979–2017 period.

Results

Conclusion