Comparison of Coincident Ozone Profiles and the Role of the Polar Vortex in the Evolution of the Ozone Layer Above Kiruna, Sweden

Abstract: This study primarily focuses on comparing coincident ozone profiles, as well as investigating the relationship between the polar vortex and the changes in the ozone layer above Kiruna, Sweden (67.85N 20.22E) during the Arctic winters 2010/2011 and 2018/2019. The instruments used are the Kiruna Microwave Radiometer (KIMRA); a millimeter wave radiometer that allows continuous observations of the evolution of ozone and other trace gases in the Arctic stratosphere, and the Microwave Limb Sounder (MLS) instrument on board the Aura satellite. The KIMRA and MLS measurements are compared to each other over the periods November 2010 to March 2011, as well as November 2018 to March 2019. Overall, the KIMRA and MLS comparison show good agreement, with KIMRA measuring more O3 in the lower stratosphere (around 50hPa) than MLS both during the daytime and nighttime. The O3 time series of KIMRA and MLS, along with the polar vortex edge based on equivalent latitudes, show minimum ozone concentrations when Kiruna was situated well inside the polar vortex.