Linkage between autumn sea ice loss and ensuing spring Eurasian temperature

This study investigated the relationship between East Siberian-Chukchi-Beaufort (EsCB) sea ice concentration (SIC) anomaly in the early autumn (September-October, SO) and northern Eurasian surface temperature (Ts) variability in the early spring (March-April, MA). Results reveal that the early autumn sea ice decrease in the EsCB Seas excites an Arctic anticyclonic anomaly in the lower troposphere in the early spring, leading to cold anomalies over central Russia. The mean temperature over central Russia drops by nearly 0.8 degrees C, and the probability of cold anomalies increases by about 30% when the EsCB SIC reduces by one standard deviation. As responses to SO EsCB sea ice loss, atmospheric anomalies of the planetary wave 2 dominate the Arctic since October-November (ON) and are in phase with the climatological mean in the troposphere. This in-phase resonance produces much more wave energy propagating into the lower stratosphere and generates an EP flux convergence anomaly in December-January (DJ), then decelerating the zonal westerly winds. One month later (January-February, JF), the attenuation of the polar vortex reaches the peak and propagates downward into the troposphere in the next 2 months with two major branches. One branch is located in Greenland and induces a zonal wave train from the North Atlantic to eastern Eurasia. Another branch is to maintain the anticyclonic anomaly in low-level over the Arctic. This configuration of atmospheric circulation anomalies provides favorable conditions for the southward invasion of Arctic cold air and makes northern Eurasia experience a colder early spring.