Investigating the Role of the Quasi-Biennial Oscillation in SAI-Induced Lower Stratospheric Heating and Moistening

Stratospheric aerosol injection (SAI) heats the lower stratosphere by absorbing shortwave and longwave radiation. Such lower stratospheric heating, and the subsequent warming of the cold point, is expected to moisten the stratosphere by permitting more water vapor to pass through the tropical tropopause layer (TTL). But it is unclear how the impact of the quasi-biennial oscillation (QBO) on the cold point temperature and stratospheric moistening changes in the presence of SAI-induced lower stratospheric heating. Conversely, it is unclear how the QBO will modulate the mean moisture increase in the stratosphere due to SAI. In this work, we investigate these impacts by performing nudging experiments in the idealized global circulation model Isca. Specifically, we perform experiments with varying combinations of SAI and QBO nudging, and we compare the stratospheric water vapor climatologies for each nudging scenario. In this presentation, we document our progress and early results. By analyzing any modulating effects the QBO has on mean stratospheric heating or water vapor transport, this study aims to better understand stratospheric processes and contribute to the ongoing research regarding the stratospheric response to a warming climate, and to possible interventions.