“Roller coaster”-type temperature fluctuations in China in 2024 winter and the asymmetric influence from the Polar front jet

Abstract

Notable “roller coaster”-type temperature fluctuations occurred in the 2024 winter in China though the seasonal mean temperature displayed a normal value. The standard deviation of daily temperature anomalies broke the highest record since 1961. By adopting an objective definition of the “roller coaster”-type temperature fluctuation, 19 events of such occurrences are observed during 1981–2024, four of which occurred in the 2024 winter. Corresponds to the temperature fluctuations in the winter, the Siberian high exhibits a synchronous variation, with significantly greater intensities in the three cold spells and considerably weaker values in the three warm spells. In contrast, the Polar front jet displays an asymmetric influence, with significantly enhanced zonal wind speeds in warm spells, while normal intensity in cold spells. The statistical results for each of the 45-day warm and cold groups in the current winter also support this conclusion.