Investigating the Influence of Blue Corona Discharges on Lower-Stratospheric Ozone Variability

Observations over recent decades show weak, and in some regions non-positive, indications of ozone recovery in the lower stratosphere, in contrast with the clearer recovery observed at higher altitudes. The processes contributing to this behaviour remain insufficiently constrained, particularly where variability is driven by episodic and spatially confined phenomena. Better constraining such processes is essential for a more complete understanding of the ongoing evolution of the ozone layer.

In this context, we investigate the potential influence of thunderstorm-related electrical discharges in the blue spectral range, also known as blue corona discharges, as a source of localized perturbations to lower-stratospheric ozone. These blue events with strong 337 nm emissions, detected by the Atmosphere Space Interactions Monitor (ASIM), are typically associated with vigorous convection and may generate reactive nitrogen and hydrogen species capable of modifying the local chemical environment.

We apply a co-location framework that combines ASIM detections with coincident limb-sounding ozone observations in the vicinity of convective systems exhibiting blue corona discharges. Initial case studies demonstrate the feasibility of this approach and reveal signatures consistent with localized ozone variability in the lower stratosphere.

Although the current number of events coincident with limb-sounding measurements does not yet permit statistically robust attribution, the results motivate the expansion of the event catalogue and the inclusion of additional observational constraints. Taken together, these findings highlight blue corona discharges as a potentially under-characterized process that may contribute to small-scale variability and regionally limited weaknesses in lower-stratospheric ozone recovery.