Monday, 10 January 2005
On The Need for Electric-Field Meters to Support Critical Lightning Hazard-Warning Decision Processes
Lightning location systems use electromagnetic signals from lightning discharges to provide the location, time of occurrence and other parameters of cloud-to-ground lightning strikes in near-real time with good efficiency and accuracy. Government agencies and private-sector companies, such as the Los Alamos National Laboratory (LANL) and Weather Decision Technologies, Inc. (WDT), use lightning location data, often in combination with network radar data, to provide lightning warning decision support products such as the LANL LTRAX and the WDT Lightning Prediction Algorithm. These lightning data analysis products predict where lightning will occur within, say, 30 minutes, on the basis of where lightning has occurred already. However, these predictions lack the rigor of objective local real-time measurement needed for many critical lightning hazard-warning decisions. Recent research reported in Lengyel (2004) suggests that a significant fraction of lightning casualties occur as a result of the first or one of the first few lightning flashes in a storm or at the end of a storm when people tend to resume outdoor activities too soon (Holle, et al., 1999). On the other hand, both anecdotal information and risk analysis (Eisenhawer and Bott, 2005, this conference) suggest that the 30 minute end-of-storm rule sometimes wastes valuable time. It is a noteworthy fact that few if any of the tens of thousands of automated weather stations in use worldwide today can report strong electric-field hazards or the occurrence of a local thunderstorm. We suggest that installation and informed use of modern low-power electric-field meters can serve to reduce risks and increase efficiency by providing vastly improved and more objective information for critical lightning hazard-warning decisions.
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