Abstract

The impact of ozone-depleting substances on global lower-stratospheric temperature trends is widely recognized. In the tropics, however, understanding lower-stratospheric temperature trends has proven more challenging. While the tropical lower-stratospheric cooling observed from 1979 to 1997 has been linked to tropical ozone decreases, those ozone trends cannot be of chemical origin, as active chlorine is not abundant in the tropical lower stratosphere. The 1979–97 tropical ozone trends are believed to originate from enhanced upwelling, which, it is often stated, would be driven by increasing concentrations of well-mixed greenhouse gases. This study, using simple arguments based on observational evidence after 1997, combined with model integrations with incrementally added single forcings, argues that trends in ozone-depleting substances, not well-mixed greenhouse gases, have been the primary driver of temperature and ozone trends in the tropical lower stratosphere until 1997, and this has occurred because ozone-depleting substances are key drivers of tropical upwelling and, more generally, of the entire Brewer–Dobson circulation.

Presenter Profile

Wang Lei , a researcher at the Academy of atmospheric science, Fudan University, and a part-time associate research fellow at the Lamont Doherty earth observation Institute of Columbia University.In 2010, he graduated from the Department of physics of the University of Toronto and engaged in the study of the stratospheric atmospheric circulation.In the 2011-2013 year, the earth and Planetary Science Department of Johns Hopkins University was engaged in the study of atmospheric chemistry - Stratospheric Climate coupling.In the past 2013-2017 years, Columbia University has been studying the atmospheric circulation and the Arctic sea ice's seasonally intraseasonal climate predictability and the long term climate change.Since December 2017, the Fudan University Atmospheric Science Research Institute, mainly engaged in Arctic sea ice in high latitudes, weather and climate prediction and predictability, and to study the dynamics of the.Personal home page:http://atmsci.fudan.edu.cn/team/wanglei.html