Low-frequency variability in the Northern Hemisphere winter: geographical distribution, structure and time-scale dependence

Abstract

The variability in all frequency bands exhibits substantial anisotropy, with meridionally elongated features arranged as zonally oriented wave trains prevailing over the continents and zonally elongated features organized in the form of north-south oriented dipole patterns prevailing over the oceanic sectors of the hemisphere. The wave trains are most pronounced in the 10-60 day variability, while the dipoles are most pronounced at lower frequencies. Eastward energy dispersion is apparent in the wave trains, but there is no evidence of phase propagation. Most of the "teleconnection patterns' identified in previous studies appear among the more prominent loading vectors. -from Authors