The dynamical evolution of Sudden Stratospheric Warmings of the Arctic winters in the past decade 2011–2021

Abstract

In this study, we analyse the dynamical evolution, and identify the major warming (MW) and minor warming events of the past 11 Arctic winters (2010/11–2020/21). During the period, MW is found in 4 winters and is in January for 2012/13, 2018/19 and 2020/21 and in February for 2017/18. A major final warming is observed in the year 2015/16. The most severe MW occurred in the 2012/13 winter, for which a rise in temperature of about 30 K is found at 60° N. The investigation of tropospheric wave forcings for the period reveals that the MW in 2012/13 and 2017/18 is forced by the combined activity of waves 1 and 2, whereas the MW in 2018/19 and 2020/21 is driven by wave 1. Studies have shown that the frequency of Sudden Stratospheric Warming (SSW) in the Arctic has been increasing since 1957/58, which is about 1.1 MWs/winter during 1998/99–2009/10. However, this frequency decreases to 0.36 MWs/winter in the period 2010/11–2020/21 and 0.74 MWs/winter in 1998/99–2020/21. An inverse relationship is observed between the period of occurrence of SSWs and total column ozone (TCO) in the Arctic for the past 11 winters (2010/11–2020/21). For instance, the temperature in the lower stratosphere in January, in which most warmings occur, shows a statistically significant high positive correlation (0.79) with the average TCO in January–March. Therefore, this study assists in understanding the relationship between inter-annual variability of ozone and the occurrence of SSWs.

Characterization of the Thermospheric Mean Winds and Circulation During Solstice Using ICON/MIGHTI Observations

“…They are presented in a manner similar to June solstice mean winds (Figure 8). Note that this period does not include any stratospheric sudden warming (SSW) events (Roy & Kuttippurath, 2022). It is seen that the zonal winds are westward (with magnitudes < 40 m s −1 ) at low-latitudes and eastward at midlatitudes ( with magnitudes < 20 m s −1 ), relatively slower than the summer winds.…”

“…In order to complement the northern summer solstice results, we have also compiled northern winter winds and circulation, including data from 16 December 2019 -31 January 2020, during which no SSWs occurred (Roy & Kuttippurath, 2022). Although the data sampling is not the same between these seasons, the results can be at least qualitatively compared.…”

“…Molecular viscosity, which increases exponentially with height, smooths out smaller-scale motions, as can be seen in daytime circulation and winds between 185 and 200 km (Figures 11 and 12). In order to complement the northern summer solstice results, we have also compiled northern winter winds and circulation, including data from 16 December 2019-31 January 2020, during which no SSWs occurred (Roy & Kuttippurath, 2022). Although the data sampling is not the same between these seasons, the results can be at least qualitatively compared.…”

Observation of vertical coupling during a major sudden stratospheric warming by ICON and GOLD: a case study of the 2020/2021 warming event

“…While the peak of temperature increase occurs over the pole (usually at North), these events produce changes across the hemisphere that last for several weeks. The lower and middle atmospheric effects of SSWs have been extensively studied (Siskind et al, 2010;Laskar et al, 2019;Gu et al, 2020;Koval et al, 2021;Roy and Kuttippurath, 2022), however the response of the upper atmosphere to SSWs is understood to a lesser degree. Nevertheless, an increasing amount of modeling efforts and observations have led to some progress in understanding SSW effects in the upper atmosphere (Karpov et al, 2018;Goncharenko et al, 2021;Koucká Knížová et al, 2021;Orsolini et al, 2022;Pedatella, 2022).…”