Exceptional Lightning

The largest flashes observed by LIS result from intense pulses of light. It has generally been thought that these so-called superbolts are a unique type of discharge that occurs in certain types of storms. Here, we use the meteorological instrumentation on TRMM to exmamine the thunderstorms that produce them.

While most optical flashes observed by the Lighting Imaging Sensor (LIS) are small, short-lived, and relatively dim, there are a number of exceptional flashes that can be noted in the LIS dataset. This study examines extreme lightning events and identifies the regions of the globe and the types of storms that produce them. We also incorporate ground-based radio lightning measurements from the National Lightning Detection Network to gain a better perspective on the discharge unmodified by the clouds.

LIS and NLDN flashes are collocated with both pixel-level TRMM Microwave Imager (TMI) and Precipitation Radar (PR) measurements (Illuminated Cloud Features – ICFs) as well Radar Precipitation Features (RPFs). Differences between land-based and oceanic lightning and in the diurnal cycles of exceptional flashes are noted. Correlations are also found between the sizes and energies of LIS flashes and NLDN flashes that suggest that despite radiative transfer concerns, LIS is still sensitive to the strength of the discharge.