Low Ozone VMR Over The Northern Hemisphere In Winter 2019/20 - Effects of a Strong PSC Winter -
The winter 2019/20 has been reported as a winter with very low ozone volume mixing ratio (VMR) over the Northern hemisphere. Only a few winters have shown less stratospheric ozone in the past. The continuous observations by the MIllimeter wave RAdiometer 2 (MIRA2) of the KIT, operated in Kiruna in Swedish Lappland, also present a strong ozone loss over the course of the winter. We will present an almost uninterrupted time series of ozone profiles between 15 and 55 km measured by MIRA2. In order to test our data analysis we compared our results to satellite data from Aura/MLS finding an overall reasonable agreement, given the very different conditions coming with these different observation geometries.
MIRA2 has been installed in Kiruna in winter 2012 and observes ozone emission from the sky at around 278Â Ghz, the millimeter wave region.
In the data for winter 2019/20 we find that ozone reduction was connected to the appearance of strong polar stratospheric cloud events which started unusually early in the winter and lasted rather long all throughout the winter period, indicating an unusually strong polar vortex with periods of unusually low stratospheric temperature over Kiruna. Furthermore, as MLS data shows, there has been an early onset of chlorine activation and denitrification, which lead to the strong ozone depletion we have seen in the ground-based data. The quantitative ozone loss analysis of our MIRA2 data set is not completed yet, but we will present the variation of the ozone column density over the course of the winter.
Created 2021-03-24 16:04:07 by Uwe Raffalski Last changed 2021-04-20 20:36:47 by Uwe Raffalski