Cloud‐to‐ground lightning in Austria: A 10‐year study using data from a lightning location system

Abstract

[1] In this paper we present lightning statistics for more than three million cloud-toground (CG) flashes located during the 10-year operation period 1992-2001 of the Austrian lightning location system (LLS) called ALDIS (Austrian Lightning Detection and Information System). Like a majority of other LLS operated worldwide, ALDIS underwent configuration changes and continuous performance improvement. Since these changes can alter the lightning statistics, we also relate the variation of the individual lightning parameters during the period of operation to changes in ALDIS configuration and performance. This analysis should be useful to other network operators and data users. Flash densities in Austria are normally between 0.5 and 4 flashes km À2 yr À1 depending on terrain. Flashes are classified as negative, positive, or bipolar. Seventeen percent of the flashes were classified as positive, and 2.3% of the total number of flashes were bipolar. Fifty percent of the positive multiple-stroke flashes were bipolar flashes with positive first stroke; this influences the positive flash multiplicity and interstroke interval statistics. Compared to many other networks, the ALDIS network reports much lower median negative peak currents. For 2001, the median first-stroke peak current for negative flashes was 10 kA. Estimated multiplicity of negative flashes for the 10-year period is affected by the algorithm that groups strokes into flashes, as well as the improved DE of the network as a result of the integration of ALDIS into the European LLS (EUCLID). This performance improvement also resulted in a higher number of single-stroke flashes.Interstroke interval and median first-stroke peak current show a clear correlation with multiplicity for negative flashes, irrespective of detection efficiency. Negative flashes with higher multiplicity show smaller average interstroke intervals and larger first stroke median peak currents. No correlation between interstroke interval and stroke order was found. On average, regions with higher flash density show slightly higher flash multiplicity.

Geographical variations of negative cloud-to-ground lightning parameters: A review

“…The median values (60 ms) was essentially the same in both locations. This value is also the same that observed by Schulz et al [28] in Austria in a 1O-year study using data from a high detection efficiency lightning location system. Many other authors have reported median values of inter stroke intervals around 60 ms [e.g., 6,17,29,30].…”

Lightning flash multiplicity in eastern Mediterranean thunderstorms

“…Both values are lower than reported in most lightning climatology studies around the world (and see Table 1). This may be explained by the dominance of winter thunderstorms in the Eastern Mediterranean, which have different characteristics than summer or tropical convective storms that are most studied globally (Cummins et al, 1998b;Schulz et al, 2005).…”

Effect of cloud-to-ground lightning and meteorological conditions on surface NOx and O3 in Hong Kong

“…As suggested by Cummins et al (1998), positive flashes with peak current lower than 10 kA should be regarded as cloud discharges. However, some other researchers pointed out that "the limit of 10 kA is somewhat arbitrary, and may be related to network configuration and climate" (Schulz et al, 2005). When the weak positive strokes (b10 kA) were removed from the dataset, the average peak current for positive strokes was from 15.2 to 20.7 kA as shown in Table S1 in the Supplementary material.…”