Analysis for the Main Characteristics of 10–30-day Intraseasonal Variations in Spring Snowmelt Anomalies over Eurasia and Associated Abnormal Circulation Patterns

Eurasian snow cover significantly influences the climate in the mid-high latitudes. Understanding the characteristics and causes of abnormal changes in Eurasian snow cover is crucial for advancing climate research and improving climate prediction accuracy. While current research has predominantly focused on interannual and interdecadal changes and climatic effects of the snow cover, there is a lack of understanding of its intraseasonal changes. This paper discusses the intraseasonal variation in spring snowmelt across different regions of Eurasia, along with related atmospheric circulation characteristics and surface-energy evolution processes, using observation and reanalysis data through statistical methods. The results reveal that anomalies in the Eurasian spring snowmelt exhibit obvious intraseasonal variation, with a dominant cycle of 10–30 days. Intraseasonal signals mainly appear in the Scandinavian Peninsula, the eastern European Plain, and western Siberia. Further analysis shows that the intraseasonal variation in the spring snowmelt in the Scandinavian Peninsula may be related to the negative phase of the Scandinavian teleconnection (SCA−), while that in the eastern European Plain may be related to the negative phase of the Eurasian teleconnection (EU−). The intraseasonal variation in western Siberia may be related to the positive phase of the Scandinavian teleconnection (SCA+). There are obvious differences in the causes of spring snowmelt anomalies in different regions. In Scandinavia, an increase in long-wave radiation is likely the main cause. Conversely, sensible heat flux anomalies may be the main causes in the eastern European Plain and western Siberia.