  As is well known, CME propagation often results in the fragmentation of the
solar atmosphere on smaller regions of density (magnetic field) enhancement
(depletion). It is expected that this type of fragmentation may have radio
signatures. The general aim of the present paper is to perform a comparative
analysis of type III solar and narrow-band type-III-like radio burst properties
before and during CME events, respectively. The main goal is to analyze radio
observational signatures of the dynamical processes in solar corona. In
particular, we aim to perform a comparison of local plasma parameters without
and with CME propagation, based on the analysis of decameter radio emission
data. We performed a comparison of usual type III bursts before the CME with
narrow-band type-III-like bursts, which are observationally detectable on top
of the background type IV radio bursts associated with CME propagation. We
focused on the analysis of in total 429 type III and 129 narrow-band
type-III-like bursts. We studied their main characteristic parameters such as
frequency drift rate, duration, and instantaneous frequency bandwidth using
standard statistical methods. Furthermore, we inferred local plasma parameters
using known definitions of frequency drift, duration, and instantaneous
frequency bandwidth.The analysis reveals that the physical parameters of
coronal plasma before CMEs considerably differ from those during the
propagation of CMEs (the observational periods 2 and 4 with type IV radio
bursts associated with CMEs). Local density radial profiles and the
characteristic spatial scales of radio emission sources vary with radial
distance more drastically during the CME propagation compared to the cases of
quasistatic solar atmosphere without CME(s) (observational periods 1 and 3).
The results of the work enable us to distinguish different regimes of plasma
state in the solar corona.
