Journal Article

Mechanisms behind consecutive extreme cold spells in Eurasia: insights from 2023 and historical analysis

Chen, Chen, Zeng, Gang, Chen, Deliang, Zhang, Shiyue

2025

Overview

Despite 2023 being the warmest year in the past 45 years, northern Europe experienced an extreme cold spell in mid-November, followed by a record-breaking cold spell in East Asia in early December. This study utilized various reanalysis datasets and a numerical model to investigate the mechanisms behind these consecutive extreme cold spells over Eurasia and whether these mechanisms can explain similar cases from 1979 to 2022. Our analysis reveals that these extreme cold spells are associated with increased snow cover over Northern Europe. Increased snow cover in early winter affects the energy balance, leading to a local cyclonic anomaly that promotes cold spells in Northern Europe. This anomaly then moves eastward, causing cold air masses to gather and strengthen in Siberia, which contributes to extreme cold spells in East Asia. Additionally, intensified upward tropospheric planetary waves due to increased snow cover weaken the stratospheric polar vortex, reducing its constraint on cold air and facilitating subsequent extreme cold spells in East Asia. Statistical analysis indicates that approximately 61.5% of the consecutive extreme cold spells over the past 44 years are influenced by these mechanisms. Furthermore, simulations with increased snow cover over Northern Europe show a higher probability of consecutive cold spells over Eurasia, supporting these findings.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: air / Air masses / Climatology / Cold / Cold air masses / Cold spell / Cold spells / data collection / Earth and Environmental Science / Earth Sciences / East Asia / Energy balance / Eurasia / Extreme cold / Geophysics/Geodesy / Mathematical models / Meteorologi och atmosfärsvetenskap / Meteorology and Atmospheric Sciences / Northern European region / Numerical models / Oceanography / Original Article / Planetary waves / Polar vortex / probability / Siberia / Snow / Snow cover / snowpack / Statistical analysis / Statistical methods / stratosphere / Stratospheric polar vortexes / Stratospheric vortices / troposphere / winter