Stratospheric ozone from limb observations: validation of the profiles, evaluation of trends and their dynamical and chemical drivers (SOLVE)

Living Planet Fellowship research project carried out by Carlo Arosio.

The stratospheric ozone layer suffered a significant decline at the end of the 20th century as a consequence of anthropogenic emissions of halogenated substances. An ozone recovery has been predicted for the current century in response to the actions taken under the Montreal Protocol and its amendments. The onset of this ozone recovery has been detected over the last decade and analysed using satellite measurements. The observed ozone changes show a complex structure as a function of altitude and latitude, which is related to the interplay between atmospheric transport and chemistry, both affected by climate change. The driving mechanisms responsible for the observed behaviour of stratospheric ozone are still insufficiently investigated.

Limb observations are an optimal tool to globally monitor the vertically-resolved composition of the stratosphere at high temporal and spatial resolution. While some limb-viewing NASA instruments are still in operation, no ESA limb sensors are currently operating, after the loss of communication with the Envisat satellite in 2012. The start of the next European – ALTIUS limb mission is not planned before 2022.

This project aims at investigating long-term ozone changes over the last two decades, by exploiting ESA and NASA limb satellite instruments. In particular, we build on the expertise at the University of Bremen acquired with SCIAMACHY data and use OMPS-LP satellite measurements to bridge the gap in limb observations before the ALTIUS launch. All these instruments exploit the same measurement technique, i.e. they collect scattered solar light in limb geometry.