AbstractLightning emits short wavelength radio waves from the very high frequency (VHF, 30–300 MHz) to ultrahigh‐frequency (UHF, 0.3–3 GHz) range. A lightning subprocess that has recently been shown to emit in this frequency range is streamer collisions. In this work, we report a modeling study of streamers colliding in ambient electric fields ranging from subbreakdown to overbreakdown values. The streamers are initiated from isolated hydrometeors similar in size to those typically seen in thunderstorms. In every case presented, the collision produces emissions extending into the UHF range. The emission spectrum from the subbreakdown ambient field cases falls off faster as frequency increases compared with the overbreakdown cases. It appears that the length of the streamers upon colliding, under the same ambient field, has a negligible effect on the shape of the spectrum. The results are important for interpreting observations of lightning processes that involve streamer collisions.
