Spatiotemporal Variations of Smoke Aerosols in the Upper Troposphere and Lower Stratosphere Observed by SAGE III/ISS

Pyrocumulonimbus (PyroCbs) can inject volcanic-scale smoke plumes into the stratosphere that encircle the globe, reside for more than a year, alter stratospheric circulations, extend the lifetime and size of the Antarctic ozone hole, and affect Earth’s radiative balance. Given the ongoing and projected increases in fire activity and severity linked to a warming climate, there is an urgent need to better understand and predict climate-scale impacts from pyroCb activity.

This study aims to investigate the spatiotemporal evolution of smoke aerosols in the upper troposphere and lower stratosphere (UTLS) and their radiative effects using multi-spectral aerosol extinction observations from Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS). Three primary research questions will be addressed: 1) what is the contribution of carbonaceous aerosols to stratospheric aerosol loading; 2) how does organic carbon (OC) and black carbon (BC) content vary with time and space, in the presence of background stratospheric aerosols; and 3) what are the radiative forcing effects of pyroCb aerosols in the UTLS. We will first infer the composition of all aerosol types in the UTLS from SAGE III/ISS multi-spectral aerosol extinction using the Normalized Derivative Aerosol Index (NDAI) approach. This presentation will present preliminary results of SAGE III/ISS analysis.