This study is among the first modeling studies on stratospheric sulfate geoengineering that interactively couple a size-resolved sectional aerosol module to well-described stratospheric chemistry and radiation schemes in a global 3-D chemistry–climate model. We found that compared with SO₂ injection, the direct emission of aerosols results in more effective radiative forcing and that sensitivities to different injection strategies vary for different forms of injected sulfur.

Using a coupled Earth system model and radiative transfer modeling we show that the radiative forcing of a winter polar mesospheric ozone loss due to energetic particle precipitation is negligible. A climate impact of a mesospheric ozone loss as suggested by Andersson et al. (2014, Nature Communications) seems unlikely. A winter polar stratospheric ozone loss due to energetic particle precipitation leads to a small warming of the stratosphere, but only a few statistically significant changes.

This work focuses on solar radiation in the tropics, more specifically on ultraviolet radiation. From ground-based and satellite observations of the chemical state of the atmosphere, we were able to model the ultraviolet measurements measured in the southern tropics with a very small error. This is a first step to modelling and predicting future ultraviolet levels in the tropics from chemistry-climate projections.

This work quantifies the contribution of the seasonal changes in ozone and water vapour to the temperature cycle in a region of the atmosphere about ~ 18 km up in the tropics (the lower stratosphere). This region is important because most of the air entering the stratosphere does so through this region and temperature fluctuations there influence how much water vapour enters the stratosphere and hence the properties of the stratosphere.