第一届未来大气科学论坛

This study focuses on the interannual variation characteristics and mechanisms of extreme low temperature events in southern China during winter from 1961 to 2018. Based on daily minimum temperature data from 1961 to 2018, extreme low temperature events were defined using a relative threshold method. Employing advanced statistical techniques such as Empirical Orthogonal Function (EOF) analysis, composite analysis, and correlation coefficient tests, this research systematically investigates the spatiotemporal patterns, atmospheric circulation backgrounds, thermal anomalies, and the influence of Arctic sea ice on the frequency of extreme low temperature events. The results reveal that the primary mode of extreme low temperature events exhibits a coherent in-phase variation across the entire southern region, accounting for a cumulative variance contribution rate of 59.11%. During periods of high-frequency extreme low temperature events, significant vertical shifts or adjustments in the East Asian Trough were observed. Additionally, a positive correlation was identified between the time coefficient series of the primary mode and both sea ice concentration and 2-meter air temperature in the Barents Sea and Greenland regions of the Arctic, which may be linked to the displacement of the Siberian High. Circulation analysis indicates that the development of the East Asian Trough and the southward movement of the Siberian High, combined with strong northerly winds in the key meridional wind regions, enhance the meridional circulation. This strengthening facilitates the transport of dry and cold air from high latitudes to East Asia, significantly influencing the frequency of extreme low temperature events in southern China. Furthermore, composite analyses of surface total heat anomalies and temperature advection anomalies further highlight the critical role of thermal factors in the formation of these extreme events. This research provides a scientific foundation for understanding the interannual variability of extreme low temperature events in southern China and their predictive mechanisms. It also offers novel insights into regional extreme weather events under the broader context of global climate change.

Frequency of extreme low temperature events；Synthetic analysis；Arctic sea ice