  Large-scale, wave-like disturbances in extreme-ultraviolet (EUV) and type II
radio bursts are often associated with coronal mass ejections (CMEs). Both
phenomena may signify shock waves driven by CMEs. Taking EUV full-disk images
at an unprecedented cadence, the Atmospheric Imaging Assembly (AIA) onboard the
Solar Dynamics Observatory has observed the so-called EIT waves or large-scale
coronal propagating fronts (LCPFs) from their early evolution, which coincides
with the period when most metric type II bursts occur. This article discusses
the relation of LCPFs as captured by AIA with metric type II bursts. We show
examples of type II bursts without a clear LCPF and fast LCPFs without a type
II burst. Part of the disconnect between the two phenomena may be due to the
difficulty in identifying them objectively. Furthermore, it is possible that
the individual LCPFs and type II bursts may reflect different physical
processes and external factors. In particular, the type II bursts that start at
low frequencies and high altitudes tend to accompany an extended arc- shaped
feature, which probably represents the 3D structure of the CME and the shock
wave around it, rather than its near-surface track, which has usually been
identified with EIT waves. This feature expands and propagates toward and
beyond the limb. These events may be characterized by stretching of field lines
in the radial direction, and be distinct from other LCPFs, which may be
explained in terms of sudden lateral expansion of the coronal volume. Neither
LCPFs nor type II bursts by themselves serve as necessary conditions for
coronal shock waves, but these phenomena may provide useful information on the
early evolution of the shock waves in 3D when both are clearly identified in
eruptive events.
