资源环境科技发展态势分析平台

A high-frequency spectral feature is identified in ground-based spectrograph data at 15-30 MHz. The feature, likely of terrestrial origin, is often recorded by a group of citizen scientists (the Spectrograph User Group) whose main interest is to observe Jupiter's radio emissions. The feature appears as radio band noise enhancement in which the frequency of enhancement increases and then decreases with time, forming a "triangular spectral feature." The teepee tent shape leads to its name (TP for short). TPs usually have well-defined leading and trailing edges. While some TPs occur in isolation, they are often seen in groups, distributed either in time or in apex frequency. While most TPs appear diffuse, close-up views of a few TPs reveal that they actually consist of discrete bursts, highly suggestive of lightning strokes as possible radiation sources. Here, we investigate the possible generation of TPs by ionospheric reflection of radiation from remote lightning storms.