Abstract
We have used the LOw-Frequency ARray (LOFAR) to image a few lightning
flashes during a particularly severe thunderstorm. The images show an
exceptional amount of VHF activity at altitudes above 10 km. Much of
this is in the form of small-scale discharges occurring seemingly
randomly around the centers of active storm cells. Because of their
small and incidental structure we refer to these as ‘speckles’. A
detailed investigation shows strong evidence that these speckles are
indicative of positive leader channels and that they are equivalent to
the needle activity seen around positive leader tracks at lower
altitudes.