Influence of Eurasian Spring Snowmelt on May and June Minimum Temperature Variability Over Northeastern China

Previous studies are more oriented toward the impacts of snow cover on seasonal mean or annual extreme climate over local and remote regions, rather than on intraseasonal variability in extreme climate. In this study, the influence of Eurasian spring snowmelt (SSD, Spring Snow water equivalent Differences) on intraseasonal extreme minimum temperature ( T min ) variability in May and June (MJ) over northeastern China and the relevant physical mechanisms during 1979–2018 are investigated. Results show that the dominant mode of Eurasian SSD features an east–west dipole pattern, characterised by reversed SSD anomalies over Siberia and Europe. Decreased Siberian SSD contributes to enlarged T min variability in MJ over northeastern China. The days with area‐averaged T min anomalies over northeastern China greater than the 90th (90P) and less than the 10th (10P) percentiles are selected to explore the relevant mechanisms. Deficient Siberian SSD corresponds to excessive evapotranspiration and snow cover in MJ with a more pronounced increase in 10P, resulting in anomalous thermal conditions and thereby modulating downstream atmospheric circulation variability. The anomalous atmospheric circulations are conducive to increased TN90P (warm nights) and TN10P (cold nights), as well as lower TNn (minimum T min ) and higher TNx (maximum T min ). Thus, increased intraseasonal T min variability appears over northeastern China due to a larger T min range and more TN90P and TN10P occurrences. Moreover, SSD is a key driver for T min variability in MJ over northeastern China, and the North Atlantic sea surface temperature provides atmospheric circulations that favour the formation of SSD distributions. The present findings highlight that Eurasian SSD is an important indicator for T min variability predictability over northeastern China.