THE COUNTING OF LIGHTNING FLASHES
Abstract
The principles involved in using lightning-flash counters are first discussed, with especial reference to the ERA and CCIR types of counter. The concept of an effective range is introduced, and it is shown how the value obtained for the effective range is influence by counter sensitivity and by the amplitude distribution of the lightning-generated signals at the thunderstorm source. The results obtained at two sites in Thailand with ERA and CCIR counters are presented, analyzed, and compared with data for Singapore. It is established that during months of high thunderstorm incidence the lightning- flash density is proportional to the square of the well-known thunderstorm-day parameter; for low-activity months, the proportionality is direct. The transition between the two laws occurs when the number of thunderstorm days per month, T sub m, is about three. Over most of Thailand T sub m always exceeds three except during the months of December through February. Seasonal and diurnal variational patterns in lightning incidence are derived. Monthly changes are related, as indicated above, to the T sub m statistic. As regards diurnal variation, from March to June thunderstorms tend to break out in the local afternoon; later in the year the peak activity moves to the early evening and night hours.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1968
- Accession Number
- AD0682023
Entities
People
- Edward T. Pierce
Organizations
- SRI International