Impact of the 2018 major sudden stratospheric warming on weather over the midlatitude regions of Eastern Europe and East Asia

Coupling between maximum temperature and ozone levels in the lower stratosphere and extreme cooling events in Northeast China

“…4, right column) compared to midlatitudes. Similar conclusion on warmer polar troposphere based in (Shi et al 2024) on the two midlatitude coolings in 2018 is confirmed by at least four cooling events in different years in this work. In addition, a similar temperature pattern is observed from climatology, where the winter temperature minimum near the surface in not located in the polar region, but shifted to 60-70N (contour -25C…”

“…4, right column) and extends poleward. The observed thermal deformation of midtropospheric air layer during extreme cold weather is generally consistent with results in (Shi et al 2024), which show a similar approach of the -20C to -30C layer to Changchun on 24 January 2018. As a result of the decrease in air temperature in the troposphere with height, surface cooling occurs due to the gradual replacement (pushing down) of a layer of warmer air in the lower troposphere by a layer of colder air from the middle troposphere (Fig.…”

“…A large enhancement of ozone, a warm center above the tropopause, deep tropopause folding, and significant downward transport of stratospheric air over the coldest surface center were found. In (Shi et al 2024), two cases of extreme cooling in the midlatitude Eastern Europe and Eastern Asia were compared. They occurred in winter 2018 under the major SSW (February) and pre-SSW (January) conditions, respectively.…”

“…However, stratospheric intrusions are considered mainly in terms of vertical air transport, especially with regard to the deep ozone penetration into the troposphere and air quality (Holton et al 1995;Kim et al 2001;Lin et al 2012;Knowland et al 2017;Zhao et al 2021;Xiong et al 2022a) and without highlighting possible contribution to appearance of surface weather anomalies. On the other hand, the stratosphere contribution to vertical thermal structure of cooling events is little studied in the CAO phenomenon (Xiong et al 2022b;Shi et al 2024).…”

“…The goal is to learn how the common features of downward stratospheric forcing described in case studies of cooling episodes (Xiong et al 2022b;Shi et al 2024) are reproduced in different winters. The annual temperature minimum in China falls in January (Song et al 2007;Li et al 2009;Qian et al 2011), as in the NH as a whole (Donohoe and Battisti 2013).…”