Observations of VHF source powers radiated by lightning

Three-dimensional lightning mapping observations have been used to estimate the peak source powers radiated by individual VHF events of lightning disc harges. The peak powers vary from minimum locatable values of about 1 W typ ically up to 10-30 kW or more in the 60-66 MHz; passband of the receivers. An energetic positive bipolar event radiated in excess of 300 kW peak power . The strongest radiation sources tended to be observed in the upper part o f storms, corresponding to the upper positive charge region, where the brea kdown is of negative polarity. The results illustrate the bidirectional nat ure of intracloud discharges, with the largest source powers being along th e negative portion of the discharge and an order of magnitude greater than the source powers along the positive portion. Overall, the source powers fo llow an approximate P-l distribution for powers above about 100 W. The radi ation sources indicate the location of the main charge regions in a storm; sample comparisons with radar data show that the main negative charge coinc ided with the precipitation core.