The modulation of Interdecadal Pacific Oscillation and Atlantic Multidecadal Oscillation on winter Eurasian cold anomaly via the Ural blocking change

Observations reveal distinct interdecadal winter Eurasian cold anomaly (ECA) centered over central Eurasia (40°–60° N, 60°–120° E), with a more southwestward extension during 1965–1976 than 2002–2013. In this paper, Ural blockings (UB) in association the Interdecadal Pacific Oscillation (IPO) and Atlantic Multi-decadal (AMO) are analyzed to explain ECA’s decadal change from 2002–2013 using reanalysis data. It is found that ECA associated negative-phase IPO (IPO−) together AMO (AMO−), while related positive-phase (AMO+) concurring IPO−. UB mainly positive North relatively short-lived rapidly retrograde both IPO+ AMO−, but long-lived shows different longitudinal movements positions IPO− AMO+. During IPO−, grows decays slowly due weak westerly winds small meridional potential vorticity gradient (PVy) mid-high latitudes high latitudes, moves westward its decay stage, causing strong anomalies upstream region (30°–50° 30°–70° E). AMO− has similar effect slow of UB. However, AMO+ slowly, eastward movement (weak) large (small) PVy (Eurasian) downstream side. Through these UB-induced sub-seasonal changes, help variation winter-mean