Analysis of a Global Moreton Wave Observed on 2003 October 28

We study the well-pronounced Moreton wave that occurred in association with the X17.2 flare/CME event of 2003 October 28. This Moreton wave is striking for its global propagation and two separate wave centers, which implies that two waves were launched simultaneously. The mean velocity of the Moreton wave, tracked within different sectors of propagation direction, lies in the range of v ≈ 900-1100 km s^-1 with two sectors showing wave deceleration. The perturbation profile analysis of the wave indicates amplitude growth followed by amplitude weakening and broadening of the perturbation profile, which is consistent with a disturbance first driven and then evolving into a freely propagating wave. The Extreme-Ultraviolet Imaging Telescope wave front is found to lie on the same kinematical curve as the Moreton wave fronts indicating that both are different signatures of the same physical process. Bipolar coronal dimmings are observed on the same opposite east-west edges of the active region as the Moreton wave ignition centers. The radio type II source, which is cospatially located with the first wave front, indicates that the wave was launched from an extended source region (gsim60 Mm). These findings suggest that the Moreton wave is initiated by the coronal mass ejection expanding flanks.