Continuing current in negative cloud‐to‐ground lightning

Shindo, Takatoshi; Uman, M. A.

doi:10.1029/jd094id04p05189

Cited by 90 publications

(78 citation statements)

References 10 publications

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“…Similar results were found in other studies [41]. It is reported that fires occurring on terrain facing suntraps were more likely to spread due to higher solar incidence and comparatively drier fuel [42].…”

Section: Environmental Determinants Of Lightning Fire Occurrencesupporting

confidence: 80%

“…Lightning is more likely to cause ignition due to a greater likelihood of a long continuum current [30,31,40]. Shindo and Uman [41] studied 90 cloud-to-ground discharges and found that only 1 of 19 single-stroke discharges was followed by a long-continuing current, whereas 21 discharges of the remaining 71 multiple-stroke discharges contained a long continuum current. These results supported our findings that increased probability of multiple-stroke discharges leaded to an increased probability of ignition.…”

Section: Environmental Determinants Of Lightning Fire Occurrencementioning

confidence: 99%

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Modeling Forest Lightning Fire Occurrence in the Daxinganling Mountains of Northeastern China with MAXENT

Chen

Niu

et al. 2015

Forests

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Forest lightning fire is a recurrent and serious problem in the Daxinganling Mountains of northeastern China. Information on the spatial distribution of fire danger is needed to improve local fire prevention actions. The Maxent (Maximun Entropy Models), which is prevalent in modeling habitat distribution, was used to predict the possibility of lightning fire occurrence in a 1 × 1 km grid based on history fire data and environment variables in Daxinganling Mountains during the period 2005-2010.We used a jack-knife test to assess the independent contributions of lightning characteristics, meteorological factors, topography and vegetation to the goodness-of-fit of models and evaluated the prediction accuracy with the kappa statistic and AUC (receiver operating characteristic curve) analysis. The results showed that rainfall, number of strikes and lightning current intensity were major factors, and vegetation and geographic variable were secondary, in affecting lightning fire occurrence. The predicted model performs well in terms of accuracy, with an average AUC and maximum kappa value of 0.866 and 0.782, respectively, for the validation sample. The prediction accuracy also increased with the sample size. Our study demonstrated that the Maxent model can be used to predict lightning fire occurrence in the Daxinganling Mountains. This model can provide guidance to forest managers in spatial assessment of daily fire danger. OPEN ACCESSForests 2015, 6 1423

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Section: Environmental Determinants Of Lightning Fire Occurrencesupporting

confidence: 80%

Section: Environmental Determinants Of Lightning Fire Occurrencementioning

confidence: 99%

Modeling Forest Lightning Fire Occurrence in the Daxinganling Mountains of Northeastern China with MAXENT

Chen

Niu

et al. 2015

Forests

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“…Our collection methodology does not allow us to estimate continuing currents directly, but some estimates can be made. As observed by [24], high multiplicity means a high probability of a continuing current. Similarly, high positive currents tend to imply continuing currents [8].…”

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confidence: 91%

Attachment of Natural Lightning Flashes to Trees: Preliminary Statistical Characteristics

Mäkelä¹,

Karvinen²,

Porjo³

et al. 2009

JLR

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Lightning attachment to trees was studied based on 37 trees that were struck in Finland in summer 2007 and 2008. The type and severity of lightning damage was correlated with multiple parameters related to the flash, the meteorological characteristics of the strike time, and the surroundings of the tree. Damage was classified into three categories: bark-loss (minor), wood-loss (extensive), end explosive (complete loss of tree material). Four statistically significant parameters were found. The absolute value of the peak flash current is strongly correlated with damage; also, an indirect argument suggests that positive flashes cause more damage than negative flashes. The amount of damage is inversely correlated with the rainfall in the previous three hours, indicating that a wet ground and tree surface protect trees against damage by providing a conducting path to the ground. The ground type also has a weaker statistically significant effect, with poorly conducting ground leading to more extensive damage. Old and rotten trees are statistically most likely to experience explosive damage. Other parameters are inconclusive. The distribution of tree heights points to the possibility that the electrogeometric method does not necessarily predict the strike probability to a given tree. In many cases, the struck trees were clearly within the protective radius of a higher structure, although this is often difficult to determine from photographs. It is therefore suggested that models of lightning flashes to trees should include both the conductivity and height of the tree. The results may be significant for remote prediction of lightning damage, as well as for understanding lightning protection of structures which include trees.

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“…Shindo and Uman [1989] once grouped the continuing current into three categories according to their duration: long continuing current with duration exceeding 40 ms, short continuing current with duration between 10 ms and 40 ms, and questionable continuing current with duration between 1 ms and 10 ms. For easy comparison, the same definition is followed in the following statistical analysis. Of all the 185 positive flashes, 133 (71.89%) contained continuing current with duration longer than 1 ms, including 36 long, 47 short, and 50 questionable continuing currents.…”

Section: Duration Of Continuing Currentmentioning

confidence: 99%

Characteristics of positive cloud‐to‐ground lightning in Da Hinggan Ling forest region at relatively high latitude, northeastern China

Qie

Wang

et al. 2013

JGR Atmospheres

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[1] In 2009 and 2010, a multistation network of fast and slow antennas was installed on the edge of a relatively high latitude forest region in Da Hinggan Ling (50.4°N, 124.1°E) of northeastern China. The documented 185 positive cloud-to-ground (CG) flashes containing 196 return strokes were analyzed in the paper. It was found that 71.89% of the positive CG flashes contained continuing current. The average duration of continuing current was short with an arithmetic mean value of 33.29 ms and a geometric mean value of 16.74 ms; only one continuing current lasted longer than 150 ms, probably because of the small size of the storm cell in this relatively high latitude region. The vast majority (94.59%) of positive CG flashes was characterized by a single stroke, and the average number of stroke per flash is 1.06. The average charge transferred by positive stroke and continuing current, based upon the analysis of five flashes with well-documented simultaneous measurements of more than five stations, was +5.2 C from a height of 6.0 km (above ground) and +10.2 C from a height of 6.4 km, respectively. The charge moment for +CG strokes ranged from +13.7 C km to +55.9 C km, while that for continuing current ranged from +29.0 C km to +96.9 C km, respectively. The preliminary breakdown process in positive CG flashes can be classified into three types, namely type S (same), type D (different), and type C (chaotic) according to the disparities in the initial polarity of bipolar pulses from the return stroke, which account for 62.92%, 23.60%, and 13.48%, respectively. According to the electric field waveforms indicative (or not indicative) of intracloud (IC) discharge, positive CG flashes are classified into four types, i.e., ordinary positive CG flash (63.78%), hybrid +CG-IC flash (21.08%), hybrid IC-+CG flash (5.41%), and hybrid IC-+CG-IC flash (9.73%). About 15.14% of the recorded positive CG flashes were byproduct of IC lightning discharge.

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Continuing current in negative cloud‐to‐ground lightning

Cited by 90 publications

References 10 publications

Modeling Forest Lightning Fire Occurrence in the Daxinganling Mountains of Northeastern China with MAXENT

Modeling Forest Lightning Fire Occurrence in the Daxinganling Mountains of Northeastern China with MAXENT

Attachment of Natural Lightning Flashes to Trees: Preliminary Statistical Characteristics

Characteristics of positive cloud‐to‐ground lightning in Da Hinggan Ling forest region at relatively high latitude, northeastern China

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