Pacific decadal oscillation modulates the decadal variations of spring Eurasian snow cover

The prominent decadal variations can be observed in the warming-induced long-term decline of Eurasian spring snow cover, which have reversed or accelerated the decreasing trend during some periods, making the understanding and prediction of the response of snow cover to climate warming more complicated. However, it remains unknown what contributes to such decadal variations. This study reveals that the spring snow cover over the mid-high latitudes of Eurasia features a consistent oscillation on the decadal timescale, which is tightly associated with the preceding winter Pacific Decadal Oscillation (PDO). The sea surface temperature anomaly related to the winter PDO can persist into the following spring and excite an anomalous wave train type circulation extending eastward from North Pacific to Eurasia. In the positive PDO phases, there is an anticyclonic and a cyclonic circulation over northern Europe and northeast Eurasia that would reduce the surface air temperature over northern Eurasia via favoring the cold advection and negative diabatic heating. Consequently, the decreased air temperature is conducive to forming the positive anomaly of snow cover. Our results can provide a valuable clue for the decadal prediction of spring Eurasian snow cover variations.