Characteristics of Winter Lightning Currents in Hokuriku District

Nakahori, K.; Egawa, Takashi; Mitani, Hiroshi

doi:10.1109/tpas.1982.317407

Cited by 22 publications

(14 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The solid dashed line represents the region of convergence along the Olt River, where convection is often initiated. than negative flashes (e.g., Nakahori et al 1982;Idone et al 1984) and are also more likely to start forest fires (e.g., Fuquay et al 1967;Rakov and Uman 2003). Fig.…”

Section: Positive Cloud-to-ground Lightning Densitymentioning

confidence: 99%

A Cloud-to-Ground Lightning Climatology for Romania

Antonescu

Burcea

2010

Monthly Weather Review

View full text Add to dashboard Cite

The first study of the characteristics of cloud-to-ground (CG) lightning in Romania, based on the data recorded by the Romanian National Lightning Detection Network (RNLDN), is presented. The data, more than 1. The monthly variation of the median first-strike peak currents has a maximum in winter and reaches a minimum in July, for both negative and positive currents. The mean diurnal cycle for total CG lightning flashes peaks between 1230 and 1430 UTC (2.2%) and shows a minimum between 0600 and 0800 UTC (0.3%).

show abstract

Section: Positive Cloud-to-ground Lightning Densitymentioning

confidence: 99%

A Cloud-to-Ground Lightning Climatology for Romania

Antonescu

Burcea

2010

Monthly Weather Review

View full text Add to dashboard Cite

show abstract

“…The negative pulse exhibits fluctuations on its tail, including a brief polarity reversal, and is followed by a slow, positive waveform, having a peak approaching 3 kA. Nakahori et al (1982) observed, in a lightning discharge to a 200-m smokestack during a winter storm in Japan, a negative initial-stage current with superimposed pulses up to 20 kA or so in amplitude followed by a positive return-stroke current pulse having a peak of 31 kA. Fernandez (1997) reported on a positive initial-stage current in triggered lightning at Camp Blanding, Florida, that was followed by leader/return-stroke sequences transferring a negative charge to the ground.…”

mentioning

confidence: 99%

A Review of Positive and Bipolar Lightning Discharges

Rakov¹

2003

Bulletin of the American Meteorological Society

141

102

View full text Add to dashboard Cite

Characteristics of lightning discharges that transport either positive charge or both positive and negative charges to the ground are reviewed. These are termed positive and bipolar lightning discharges, respectively. Different types of positive and bipolar lightning are discussed. Although positive lightning discharges account for 10% or less of global cloud-to-ground lightning activity, there are five situations that appear to be conducive to the more frequent occurrence of positive lightning. These situations include 1) the dissipating stage of an individual thunderstorm, 2) winter thunderstorms, 3) trailing stratiform regions of mesoscale convective systems, 4) some severe storms, and 5) thunderclouds formed over forest fires or contaminated by smoke. The highest directly measured lightning currents (near 300 kA) and the largest charge transfers (hundreds of coulombs or more) are thought to be associated with positive lightning. Two types of impulsive positive current waveforms have been observed. One type is characterized by rise times of the order of 10 μs, comparable to those for first strokes in negative lightning, and the other type is characterized by considerably longer rise times, up to hundreds of microseconds. The latter waveforms are apparently associated with very long, 1–2 km, upward negative connecting leaders. The positive return-stroke speed is of the order of 108 m s−1. Positive flashes are usually composed of a single stroke. Positive return strokes often appear to be preceded by significant in-cloud discharge activity, then followed by continuing currents, and involve long horizontal channels. In contrast to negative leaders, which are always optically stepped when they propagate in virgin air, positive leaders seem to be able to move either continuously or in a stepped fashion. The reported percentage of bipolar flashes in summer storms ranges from 6% to 14% and from 5% to 33% in winter storms. Bipolar lightning discharges are usually initiated by upward leaders from tall objects. It appears that positive and negative charge sources in the cloud are tapped by different upward branches of the bipolar-lightning channel.

show abstract

“…In the thunderstorms that occur in temperate regions the positive lightning contributes to 5%-20% of the ground flashes whereas in tropics it is about 3%-5% [9]. Some exceptional statistical observations are reported in the winter lightning of Japanese and Korean coastal regions where the percentage of positive lightning may reach values as high as 70% [1][2][3][4][5][6][7][8].…”

Section: Characteristics Of Lightning Currentsmentioning

confidence: 99%

“…The peak current is about 30 kA on average for first stroke and about 15 kA for subsequent strokes of negative flashes [12,13]. Positive flashes usually have a single stroke of which the currents have much larger peak value, slower rising edge and longer total duration [1,4,12,13]. A majority of the positive return stroke currents carry a large amount of charge during the long stroke phase [12,13].…”

Section: Characteristics Of Lightning Currentsmentioning

confidence: 99%

“…It is worth mentioning that a majority of the busy sea ports in tropics are located in the most lightning dense regions in the world (Singapore, Kochi, Johor, Klang, Colombo, Legazpi etc.). Furthermore, many of the ports in Japan and Korea (such as Kobe and Busan) experience dangerous positive lightning during the winter [1][2][3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Protection of Naval Systems Against Electromagnetic Effects Due to Lightning

Gomes¹,

Kadir²

2011

PIER

View full text Add to dashboard Cite

Abstract-This study investigates possible lightning threats to naval crafts, especially those sailing in the shallow waters of tropical oceans where thunderstorms prevail throughout the year and Far-East Asian region where dangerous positive lightning is a significant characteristic in winter thunderstorms. It is empathized that sea water acts as nearly a perfect conductor thus lightning electromagnetic transients propagate over the sea with almost zero attenuation of amplitude and high frequency components intact. The ratio between the peak electric fields at 5 km from the lightning channel, after fields propagate over dry soil and over sea water is 0.75. The ratio between the peak electric field derivatives under the same conditions is 0.1. Such small ratios are observed in the magnetic fields and their time derivatives as well. Apart from the conductivity, the topological irregularities of the plane over which propagation takes place also contribute to further attenuation of fields and their time derivatives. This makes marine naval systems more vulnerable to lightning induced effects than their ground-based counterparts. The paper discusses in detail the lapses of existing naval standards in the defense of electrical and electronic systems against both direct lightning currents and induced effects of nearby lightning. Consequently we propose the development of a dedicated standard for the lightning protection of naval systems, with the inclusion of several significant recommendations specified in this paper.

show abstract

Characteristics of Winter Lightning Currents in Hokuriku District

Cited by 22 publications

References 1 publication

A Cloud-to-Ground Lightning Climatology for Romania

A Cloud-to-Ground Lightning Climatology for Romania

A Review of Positive and Bipolar Lightning Discharges

Protection of Naval Systems Against Electromagnetic Effects Due to Lightning

Contact Info

Product

Resources

About