1996

Schulz W., G. Diendorfer: Detection Efficiency and Site Errors of Lightning Location Systems

14^th International Lightning Detection Conference (ILDC), Tucson, Arizona, 1996 Detection efficiency (DE) is one of the most important system performance parameters of a lightning location system. We present a theoretical model for the DE, which does not need the assumption of a theoretical peak current distribution. For testing the model we split the Austrian lightning location network into two separate networks. After correcting the number of flashes of the two different networks for DE we get about the same value for both networks. In the second part of this paper we show, that the cable connections of the direction finder have a significant influence on the site error of a sensor. PDF File (218 KB)

Diendorfer G., W. Schulz: Unusual Lightning Strikes in Austria During a Winter Thunderstorm

14^th International Lightning Detection Conference (ILDC), Tucson, Arizona, 1996 On December 26, 1996, during a late evening winter thunderstorm, several flashes with extraordinary characteristics were located by the Austrian Lightning Detection Network ALDIS. In a time period of about 90 minutes 22 flashes with a total of 435 strokes were detected at almost the same location on top of a mountain. One of the flashes had a multiplicity of 40 strokes in 1442 ms, five more flashes had a multiplicity of higher than 30 strokes. PDF File (66 KB)

Schulz W., G. Diendorfer, R. Iorio, F. Hofbauer, A. Stimmer: Correction of Lightning Density and Lightning Current Distributions for Detection Efficiency

23^th International Conference on Lightning Protection (ICLP), Firenze, Italy, 1996 Lightning location systems are primarily used to determine the coordinates of the lightning striking point. These systems also provide information about the peak amplitude of the lightning current. In literature we can find several ground flash densities and lightning peak current distributions determined from data collected by lightning detection systems. Usually the effects of a limited detection efficiency of those systems to the ground flash density and the peak current distribution are not taken into account. Detection efficiency of a location system mainly depends on the network configuration (number of sensors and baseline) and the setup of the direction finder threshold. In this paper we present a method for correcting at least partly errors caused by the limited detection efficiency based on a simple probability approach. We take into account the network configuration, the threshold and the saturation limits of the used DF's. PDF File (76 KB)

Schulz W., G. Diendorfer: Site Error Correction with Time Information

23^th International Conference on Lightning Protection (ICLP), Firenze, Italy 1996 Site error correction is an important process in the operation of a lightning location system based on magnetic direction finder technology. Different algorithms have been published in literature to correct systematic angle errors [Schulz and Diendorfer, 1993; Soerenson, 1995]. These algorithms use the angle information only for the correction, because the old version of the LLP system only provided the angle information of a flash. With the new IMPACT technology, in addition to the angle also the arrival time of the signal at the site is measured. So it is possible to correct the site errors more efficiently by including time information in the site error algorithms. In this paper we show, how site error correction can be performed including the time information and how the use of the additional time information improves the results. In addition to the correction of the angular error it is also possible to correct the propagation error of the signal approximately. The improvement in data quality of the localized strokes due to the application of a time correction is evaluated. PDF File (4,9 MB)