Objective Airport Warnings over Small Areas Using NLDN Cloud and Cloud-to-Ground Lightning Data

Abstract

ightning can have a significant impact on ground-crew and other operations at airports, resulting in a cascade of delays beyond the immediate locations. Measures of these impacts have not been presented previously in a comprehensive approach for a variety of factors. Prior approaches typically used lightning data within outer observation radii of varying sizes to anticipate cloud-to-ground (CG) flashes in a smaller inner warning area such as an airport. The goal of this paper is to address issues related to the balance between safety and the efficiency of lightning warnings for such situations. The first of two topics addressed in this study is to examine the value of adding cloud pulses to CG strokes. The detection efficiency of the U.S. NLDN for cloud pulses increased to about 50% by late summer 2013, so NLDN data during the entire 2014 summer are considered at 10 locations. Verification is performed for the occurrence of NLDN-detected CG strokes at the airports. Cloud pulses were found to improve the 2-min probability of detection by 13% compared with CG strokes only. The second topic of the study is the reduction of the inner warning area from the size of an entire airport to a small section of the airport, from a radius of 4.8 to 0.5 km. The probability of detection with a 2-min lead time increases to over 0.90 for the smaller area, while the false alarm ratio also increases substantially when CGs plus cloud pulses are included.