Evaporation and Fragmentation of the Electrified Droplets in the Polar Clouds during Spring Season as a Key Mechanism of the Ozone Depression Formation

Abstract

This study focuses on the role of the charged particles in the formation of the springtime ozone depression in the polar atmosphere. Analysis of experimental data collected in the polar atmosphere indicates that the small charged particles, predominantly ion clusters, can play a key role in the ozone molecules destruction and springtime ozone depression. The formation of these particles increases strongly during the spring season in the process of evaporation and fragmentation of the cloud-charged droplets in the lower stratosphere and upper troposphere. Additionally, small charged particles can also affect the formation and accumulation of chlorine monoxide under cold conditions of the lower stratosphere. At the same time, the chlorine mechanism of ozone destruction cannot completely explain the ozone depression formation, which probably takes place not only inside the polar vortex in the lower stratosphere but outside it also, both at the altitudes of the lower stratosphere and upper troposphere. The assumption that the charged particles play an important role in the process of ozone depression formation was put forward by previous studies, but in this research work, this assumption has been additionally confirmed, which is the springtime growth of ion clusters concentration as a result of the droplet's evaporation and defragmentation in the polar atmosphere is a key mechanism of the ozone depression formation. We simulated the process of evaporation and fragmentation in the case of a 10-micron size droplet, which implies the possible catalytic cycles of ozone destruction with the ion clusters. For the first time, the role of the Earth's magnetic field and the Polar vortex wind in the unipolar charge accumulation on the cloud particles in the lower stratosphere and upper troposphere not only inside the Polar vortex but also outside of it was substantiated. This fact in our point of view can give rise to the large-scale springtime ozone depression, spreading over the midlatitudes, which size is vastly greater than it is commonly supposed.