Analysis of an event of short term ozone variation using a Millimiter-Wave Radiometer installed in subpolar region

Abstract

Abstract. Subpolar regions in the southern hemisphere are influenced by the Antarctic polar vortex during austral spring, which induces high and short term ozone variability at different altitudes mainly into the stratosphere. This variation may affect considerably the total ozone column changing the harmful UV radiation that reaches the surface. With the aim to study ozone with high time resolution at different altitudes in subpolar regions, a Millimeter Wave Radiometer (MWR) was installed at the Observatorio Atmosférico de la Patagonia Austral (OAPA), Río Gallegos, Argentina, (51.6° S; 69.3° W) by 2011. This instrument provides ozone profiles with time resolution of ~ 1 hour which enables studies of short term ozone mixing ratio variability from 25 to 70 km in altitude. This work presents the MWR ozone observations between October 2014 and 2015 focusing on an atypical event of polar vortex and ozone hole influence over Río Gallegos detected from the MWR measurements at 27 and 37 km during November of 2014. The advected potential vorticity (APV) calculated from the high-resolution advection model MIMOSA (Modélisation Isentrope du transport Méso-échelle de l'Ozone Stratosphérique par Advection) was also analysed at 675 and 950 K to understand and explain the dynamic at both altitudes and correlate the ozone rapid variation during the event with the passage of the polar vortex. In addition, the MWR dataset were compared for first time with measurements obtained from Microwave Limb Sounder (MLS) at individual altitude levels (27 km, 37 km and 65 km) and with the Differential Absorption Lidar (DIAL) installed in OAPA to analyse the correspondence between the MWR and independent instruments. The MWR-MLS comparison presents reasonable correlation with a mean bias error of +5 %, −11 % and −7 % at 27 km, 37 km and 65 km, respectively. The MWR-DIAL comparison at 27 km presents also good agreement with a mean bias error of −1 %.