The potential of high performance, regional total lightning networks and enhanced display products for public safety and broadcast meteorology applications

Vaisala has been operating a regional total (cloud and cloud-to-ground) lightning demonstration network in the Dallas-Fort Worth, TX area since 2001. This Lightning Detection and Ranging (LDAR II) network builds upon the VHF lightning detection technology first developed at NASA Kennedy Space Center called LDAR. This same technology has also been modified by New Mexico Tech into the Lightning Mapping Array (LMA). The Dallas-Fort Worth (DFW) LDAR II network detects over 90% of all cloud and cloud-to-ground lightning within 120 kilometers of DFW International Airport. LDAR II's ability to map these lightning flashes in three dimensions, coupled with its high flash detection efficiency, allow a complete three-dimensional reconstruction of the lightning channels in a thunderstorm. Data from this network is currently being used for real-time thunderstorm monitoring at the Fort Worth National Weather Service Office.

Current media and safety display products show cloud-to-ground (CG) lightning. This information only conveys part of the CG lightning threat that exists to the public during thunderstorm activity. The DFW LDAR II network has regularly detected lightning flashes that extend over 50-100 kilometers in length. These flashes pose a significant safety risk to the general public because, at any time, they are capable of producing a CG flash along their path. Many examples of these horizontally extensive lightning flashes will be shown using unique display tools developed by Vaisala. CG-only lightning displays are also not very useful for monitoring thunderstorm growth and dissipation and severe weather trends. Approximately 70% of all lightning stays in the cloud and never reaches the ground. In fact, some thunderstorms produce greater than 10 cloud flashes for every CG flash and a few may only produce cloud lightning for the first 60 minutes of a severe thunderstorm. Total lightning detection provides a rich dataset that can be used with radar data to improve severe weather warnings and potentially increase the lead time for these warnings. Since the total lightning data is a continuous data stream, it can provide valuable information on thunderstorm growth and dissipation trends and severe weather development between radar volume scans.

A couple of unique storm animation tools will be presented. These tools provide easily-interpreted simultaneous displays of storm/cell location, total lighting rate, and/or cloud-to-ground lightning rate. These fields can be accurately superimposed on base maps of geo-coded information such as terrain height. Finally, Vaisala's VHF total lightning mapping sensors using interferometric technology will be discussed. These sensors provide wide area, 2-dimensional VHF total lightning mapping with lower accuracy than LDAR II.