Two Leading Modes in the Evolution of Major Sudden Stratospheric Warmings and Their Distinctive Surface Influence

Abstract Height‐time domain empirical orthogonal function (EOF) analysis is conducted to extract the dominant variations in evolution of sudden stratospheric warming events (SSWs). The EOF1 corresponds weak (I+) and strong (I−) polar vortex before onset SSWs EOF2 indicates (W+) (W−) during SSWs. development I− associated with stronger eddy heat flux contributed by planetary wavenumbers 1 2, whereas I + related wavenumber 1. W are linked both while happening W− I+ W+ can exert influence on surface such as negative phase North Atlantic Oscillation, which that different initial states intensities lead influence. This could help better predict tropospheric response following