Atmospheric teleconnections and regional-scale atmospheric anomalies over the Northern Hemisphere

Atmospheric teleconnections in the Northern Hemisphere such as Arctic Oscillation(AO),North Atlantic Oscillation(NAO) and Pacific-North American(PNA) teleconnection can be explained by the physical decomposition of geopotential height.The result shows that the AO reflects planetary-scale zonal-mean anomalies in the Arctic region;the PNA results from persistent regional-scale atmospheric anomalies;NAO is a combined result of both planetary-scale zonal-mean and regional-scale anomalies.The rotated empirical orthogonal function(REOF) of planetary-scale zonal-mean and regional-scale anomalies not only confirms the already known regional and wave trains,but also discovers new patterns,such as twin dipole oscillations in the Arctic region,Euro-Asia Oscillation(EAO) and Atlantic-Euro-Asia(AEA) wave-train pattern.These or wave trains are linked to adjacent regional weather anomalies and climate anomalies.