The Polar/ Eurasia pattern appears in all seasons. The positive phase of this pattern consists of negative height anomalies over the polar region, and positive anomalies over northern China and Mongolia. This pattern is associated with fluctuations in the strength of the circumpolar circulation, with the positive phase reflecting an enhanced circumpolar vortex and the negative phase reflecting a weaker than average polar vortex.
The Polar/Eurasian pattern is mainly associated with above-average temperatures in eastern Siberia and below-average temperatures in eastern China. It is also associated with above-average precipitation in the polar region north of Scandinavia.
The Polar/Eurasian pattern can exhibit strong low-frequency variability. For example, a negative phase of the pattern prevailed during 1955-1961, followed by appositive phase during 1964/65 - 1969/70. Similar persistent negative and positive phases of the pattern were observed during the 1980s-1990s.