A Comparison of Horizontal Cloud-To-Ground Lightning Flash Distance Using Weather Surveillance Radar And The Distance Between Successive Flashes Method

This is a AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH SCHOOL OF ENGINEERING report procured by the Pentagon and made available for public release. It has been reproduced in the best form available to the Pentagon. It is not spiral-bound, but rather assembled with Velobinding in a soft, white linen cover. The Storming Media report number is A983163. The abstract provided by the Pentagon follows: On April 29th, 1996 an airman servicing a C-130 aircraft on Huriburt AFB Florida was struck and killed by a lightning flash that traveled an estimated 7 to 10 miles from storms south of the airfield. Ten other workers were injured in the incident. The fatal flash occurred just 8 minutes after the base weather station allowed a lightning advisory to expire. The incident brought to question the adequacy of lightning advisory criteria. Very little research has been done on the horizontal distance that cloud-to-ground lightning flashes occurs from the center of a thunderstorm. This thesis used the WSR-88D method, which used the WSR-88D Algorithm Testing And Display System (WATADS) to calculate the distance from a lightning flash to a thunderstorm centroid. The WSR-88D method was compare with a lightning spatial and temporal clustering method known as the Distance Between Successive Flashes (DBSF) method. This method can use enormous amounts of lightning data, and is well suited to accomplish a climatology of horizontal flash distance from a lightning centroid. For the combined April and July 1996 data used in this thesis, the average percentage of lightning flashes that occurred beyond the 5 nautical niile lightning safety radius outlined in AFOSH 91-100 for both the WSR-88D method and the DBSF method was 30.86%. This result questions the adequacy of the 5 nautical mile lightning safety distance criterion currently being used at most United States Air Force Bases for protection both life and property.