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Subject matter of this paper is the analysis of the total of six upward positive lightning initiated from the Peissenberg Tower, Germany. All of them occurred during the cold season from February to April in the years 1997 to 1999. Three of them were initiated without nearby preceding lightning activity (called “self-initiated” upward lightning) and the other three occurred during nearby lightning activity (called “other-triggered” up-ward lightning). The analysis suggests that the other-triggered upward lightning is a downward lightning involving a relatively long upward connecting leader. The first current component, however, was different from the current of a first return stroke of a positive cloud-to-ground flash. On average, the duration was 15.7 ms, the maximum was 4.37 kA, and the charge was 13.3 C. Due to the long duration and the relatively low current, the first current component is more consistent with the initial continuous current (ICC) of an upward lightning. The initial period of the ICC exhibits a slowly rising portion lasting about 1 ms. During that period, the ICC was superimposed by weak current pulses. The arithmetic means of the pulse peak and the pulse duration were 0.49 kA and 9.6 μs, respectively. The average leader velocity was \bf \bf 2.3 \, \bm \times \,\bf 10^\bf 5 m/s and the average leader charge density was \bf 1.02 \, \bf \times\, \bf 10^\bf -3 C/m. Much stronger current pulses were observed after that initial period. Then, the arithmetic means were 5.3 kA for the pulse peak and 46.6 μs for the pulse duration. The ICC of the self-initiated upward lightning did not exhibit such an initial slowly rising portion with weak superimposed current pulses. The ICC immediately increased to several kilo-amperes involving strong current pulsation. For the ICC, the arithmetic means were 58 ms for the duration, 6.4 kA for the maximum, and 105 C for the charge. For the current pulses, the arithmetic means were 5.7 kA for the pulse peak and 19 μs for the pulse duration. The leader charge density was estimated to be up to several 10 mC/m. [ABSTRACT FROM PUBLISHER]

In this study, we analyze a lightning event, which occurred on March 20, 2020 at 8:05 pm. Three other-triggered upward lightning developed simultaneously from the 150 m high Peissenberg Tower and from two small structures, a 35 m high mast and a 25 m high Church Tower. The velocity of the upward leaders ranged from 2.1 × 104 to 4.1 × 104 m/s. In addition, to these upward leaders, the total of 51 isolated leaders were observed. These leaders had no contact to the lightning channel or to other leaders or to objects at ground, i.e., most of them did not develop along a path of the decayed channel of a previous leader. Therefore, it is doubtful whether the isolated leaders may be recoil leaders. The lightning to the Peissenberg Tower was a bipolar flash with a current, which contained several (unusual) positive and negative components. The first component was a negative initial continuous current (ICC), followed by a strong negative current component, with a maximum of 4.1 kA and a duration of 40.2 ms. This current component was superimposed by a pulse train of 26 extremely strong current pulses with peak values up to 1.87 kA. The negative current component was followed by a positive current pulse with a peak value of 31 kA, a 10%–90% risetime of 1.80 ms, an action integral of 0.68 MJ/Ω, a full width on half maximum of 0.67 ms and a duration of 15.7 ms. The positive current pulse was superimposed by strong oscillations with the frequency of about 5 kHz and with amplitudes up to 10.2 kA. After its cessation, the positive current pulse turned into a negative continuing current with the duration of 217 ms, the maximum of 245 A, and the transferred charge of 18.0 C. The negative continuing current was followed by a negative return stroke which in turn was followed by a positive continuing current, which lasted 19.7 ms and had a maximum of 173 A. Finally, a second negative return stroke occurred, which was followed by a short negative continuing current with an M-component. [ABSTRACT FROM AUTHOR]

Events of a class, consisting of the subsequent strokes of multiple-stroke flashes presenting the largest peak current, have features that make their effects very severe in terms of insulation stress, notably the combination of a relatively intense peak current and a very short front time. According to instrumented-tower measurements, their median peak current 27.2 kA is around 55% higher than that of the whole set of subsequent strokes and their median front time is around 0.7 μs. The frequency of such events is relatively significant since around 80% of lightning flashes are multiple-stroke flashes. [ABSTRACT FROM AUTHOR]