Effects of Sudden Stratospheric Warming Events on the Distribution of Total Column Ozone over Polar and Middle Latitude Regions

Abstract

In winter the polar stratosphere is extremely cold. During the Sudden Stratospheric Warming events, the polar stratospheric temperature rises concurrently zonal-mean zonal flow weakens over a short period of time. As the zonal flow weakens, the stratospheric circulation becomes highly asymmetrical and the stratospheric polar vortex is displaced off the pole. The polar stratospheric temperature rises by 50˚C and the stratospheric circumpolar flow reverses direction in a span of just few days. Sudden Stratospheric Warming (SSW) leads to significant changes in the rate of several chemical reactions which occur in the polar stratosphere. During such events, the dynamical fields in the polar stratosphere completely altered and columnar ozone changed. This study concentrated on the variability of winter polar vortex, meridional temperature gradient and associated changes in the Total Column Ozone (TCO) over the polar and middle latitude regions. It is found that changes in the amount of column ozone are positively correlated with polar lower stratospheric temperature with colder (warmer) temperature correlating with less (high) amount column ozone. But in the middle latitude region we observed negative correlations between ozone concentration and stratospheric temperature. In almost all cases there is sudden increase of ozone concentration over the pole and after few days the value is reduced when the warming effect is weak. During SSW events there observed an increase of 30 DU in TCO from the average value over the pole and if the SSW is strong TCO is found to rise by 50 DU. But in the middle latitude approximately 10 DU increase is noted. From the above results it may be concluded that variability of column ozone depends on dynamic and stratospheric chemistry over the poles and in middle latitude the variability can be attributed to the dynamical aspects. Anomaly of column ozone is higher during sudden stratospheric warming events over both polar and middle latitude region. The meridional temperature gradient reverses first and after two days polar vortex changes its V. Madhu 303 direction or weakens followed by an increase of column ozone over the polar region. An increase of 30˚ Kelvin in the average temperature value noted over the polar region during sudden stratospheric warming events.

Stratospheric Warming Events in the Period January–March 2023 and Their Impact on Stratospheric Ozone in the Northern Hemisphere

“…Some studies of long-term variations of the protective ozone layer at mid-latitudes in the Northern Hemisphere and in particular over Bulgaria in recent decades show that it is relatively stable, with no significant trends being observed [2,12]. It is well known that the strongest short-term variations in ozone concentration and total stratospheric ozone are observed during the winter seasons, especially during Sudden Stratospheric Warming [13].…”

“…Some studies of long-term variations of the protective ozone layer at mid-latitudes in the Northern Hemisphere and in particular over Bulgaria in recent decades show that it is relatively stable, with no significant trends being observed [2,12]. It is well known that the strongest short-term variations in ozone concentration and total stratospheric ozone are observed during the winter seasons, especially during Sudden Stratospheric Warming [13]. Stratospheric warmings are large-scale anomalies in the winter regime of the stratosphere which cause strong variations in temperature, pressure, and wind speed without any external factor being identified for their occurrence and without the presence of any additional energy into the stratosphere [14].…”

Observation and modeling of high-<sup>7</sup>Be concentration events at the surface in northern Europe associated with the instability of the Arctic polar vortex in early 2003

“…Due to its relatively long radioactive half-life (53.22 d) and its cosmogenic origin in the upper troposphere and lower stratosphere (UT-LS) (Lal and Peters, 1967), 7 Be is considered a tracer for intrusion of stratospheric air into the troposphere and large-scale subsidence (e.g., Liu et al, 2016;Chae and Kim, 2019;Heikkila et al, 2008). The variability of the 7 Be activity concentration in surface layers is driven by both static and dynamic factors, e.g., geographical location of the monitoring sites (e.g., Hernández-Ceballos et al, 2015), seasonal atmospheric processes driving transport of carrier aerosols (Lal and Peters, 1967), stratosphere-troposphere air mass exchange (Cristofanelli et al, 2003(Cristofanelli et al, , 2009Putero et al, 2016;Brattich et al, 2017a), synoptic influences (Usoskin E. Be concentration events at the surface in northern Europe et al, 2009), downward transport in the troposphere (Lee et al, 2007), solar activity, and dry and wet deposition (e.g., Hernández-Ceballos et al, 2015, 2016Ioannidou and Papastefanou, 2006).…”

“…Further, over the last decade many studies have investigated the 7 Be records in northern Europe (Leppänen et al, 2010(Leppänen et al, , 2012Leppänen and Paatero, 2013;Sarvan et al, 2017;Leppänen, 2019), one of the three regions in Europe identified with a distinct 7 Be behavior in the surface air (Ajtić et al, 2016(Ajtić et al, , 2017Hernández-Ceballos et al, 2015, 2016. Among these studies, Ajtić et al (2016) analyzed the 7 Be concentration measured in Helsinki, Finland, over 25 years (1987 and pointed out a relatively high number of 7 Be extremes occurring over autumn and winter: more specifically, 10 % of the highest 7 Be concentrations (above the 90th percentile) were observed in the cold season (October-March).…”

“…While major SSW, the so-called vortex split , can even cause the stratospheric vortex to break down during midwinter (Waugh et al, 2017), vortex displacements are instead characterized by a shift of the polar vortex off the pole and its subsequent distortion into a "comma shape" during the extrusion of a vortex filament . Previous works suggested that the occurrence of SSW events is capable of greatly perturbing the polar vortex and hence the stratospheric potential vorticity (PV) distribution (e.g., Matthewman et al, 2009) and the vertical distribution of ozone (e.g., Sonneman et al, 2006;Madhu, 2016). Additionally, the meteorological conditions associated with SSW events in the Arctic have been linked with the occurrences of 7 Be winter extremes, especially in the presence of a very high Scandinavian teleconnection index (Ajtic et al, 2018).…”