Determining the Horizontal Distance Distribution of Cloud-to-Ground Lightning

<p>Military installations airports sporting events and other facilities curtail operations when cloud-to-ground (CG) lightning is present. The National Lightning Detection Network records approximately 20 million lightning flashes each year (Orville and Huffines 1999). Because of the frequency and random nature of CG lightning more people become casualties to lightning each year than to either tornadoes or hurricanes. Lightning specific warning criteria are not standard and appear to have evolved over time as a result of increasing the distance in response to lightning incidents until the proper balance between threat and impact were achieved rather than through research and lightning data analysis. This research effort attempted to quantify what constitutes a safe distance when lightning is present. The method used in this research project groups lightning flashes into clusters using spatial and temporal constraints. However not all flashes meet the time and distance criteria for clustering and remained outside of the grouped flashes and as such are identified as isolated flashes. These isolated flashes are outliers in the data set but are precisely the flashes that prove most dangerous. For this reason not only were the distances between each flash and cluster center studied but also the distances between each isolated flash and its nearest neighboring flash. Distributions for both distances were studied for the continental U.S. by season.</p><p>This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact and remains as true to the original work as possible. Therefore you will see the original copyright references library stamps (as most of these works have been housed in our most important libraries around the world) and other notations in the work.</p><p>This work is in the public domain in the United States of America and possibly other nations. Within the United States you may freely copy and distribute this work as no entity (individual or corporate) has a copyright on the body of the work.</p><p>As a reproduction of a historical artifact this work may contain missing or blurred pages poor pictures errant marks etc. Scholars believe and we concur that this work is important enough to be preserved reproduced and made generally available to the public. We appreciate your support of the preservation process and thank you for being an important part of keeping this knowledge alive and relevant.</p>