Spike-type III burst pairs represent a distinct class of solar radio emissions in which clusters of spike-like bursts appear atop the high-frequency onset of type III bursts. Using high time–frequency resolution data from the Chashan Broadband Solar radio spectrometer at meter wavelengths (CBSm), we present the largest statistical study to date of such events, comprising 502 spike–type III pairs from 35 events recorded between November 2023 and October 2025. We find that spike-like clusters systematically precede their associated type III bursts by 0.5--3 s in time (∼87% of pairs) and by 3--30 MHz in frequency (∼80%), a temporal and spectral offset that differs from earlier reports. The spike-like clusters exhibit diverse morphologies, including point-like, blob-like, drifting, and diffuse structures, with durations of ∼0.5--5 s and bandwidths of 15--150 MHz. Bidirectional drifting structures with rates of ∼20--100 MHz s -1 are observed, consistent with source motion both toward and away from the Sun. Furthermore, spike emission is predominantly strongly circularly polarized, with more than 64% of clusters showing maximum polarization exceeding 0.6, in stark contrast to the generally weak polarization of type III bursts. These findings point to an origin of the spike radiation in a multi-scale, inhomogeneous, and highly dynamic electron-acceleration region, providing novel observational constraints on the mechanisms underlying coherent solar radio bursts.
Chang et al. (Wed,) studied this question.