A Study of Radar Echoes and their Relation to Lightning Discharges of Thunderclouds in the Hokuriku District

Michimoto, Koichiro

doi:10.2151/jmsj1965.71.2_195

Cited by 56 publications

(36 citation statements)

References 9 publications

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“…This height is known to be very important in the charge separation (Takahashi, 1978;Rakov and Uman, 2003), which is considered to be the 1st order approximation for the charge height. The location of the -10°C isotherm above the ground level was found to be a decisive factor for lightning activity in winter (Michimoto, 1993), and no lightning is observed in situations when it is at or below 1.4 km. The average (or mean) value is plotted as a square against each month, with the standard deviation shown as a bar.…”

Section: Analysis Results (Monthly Basis)mentioning

confidence: 94%

“…There are two fundamental ones; (1) sprites that develop in the mesosphere (Sentman and Wescott, 1995) and (2) elves which are detected in the lower ionosphere (Fukunishi et al, 1996). It is generally agreed that elves are caused by heating and ionization by the electromagnetic pulse (EMP) from ground flashes (Nickolaenko and Hayakawa, 1995;Inan et al, 1996). Whereas, it is generally suggested that sprites occur due to the quasi-electrostatic (QE) electric field originating from the negative charge left in the thundercloud after the parent positive cloud-to-ground (CG) strokes (Pasko et al, 1995(Pasko et al, , 1997a.…”

Section: Introductionmentioning

confidence: 99%

“…The details of the observing system are given in Matsudo et al (2007). Many sprites were observed in this area (Fukunishi et al, 1999;Hobara et al, 2001;Adachi et al, 2002;Hayakawa et al, 2004;Hobara et al, 2006), because of the well-known characteristics of winter lightning such as extremely low cloud top, large charge transfer, and approximately the 50 % share of positive CGs (Takeuti et al, 1978;Michimoto, 1993). In our recent paper by Matsudo et al (2007), we described several additional kinds of sprite structure.…”

Section: Introductionmentioning

confidence: 99%

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Morphology of winter sprites in the Hokuriku area of Japan: Monthly variation and dependence on air temperature

Myokei

Matsudo

Asano

et al. 2009

JAE

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Abstract. Continuous observations of mesospheric optical emissions (sprites) were performed from two optical sites, Shimizu and Chofu during the period of seven months from November 2004 to May 2005, with the target of specific winter sprites in the Hokuriku area of Japan (in the coast of Japan Sea). Two different kinds of analysis have been performed; one is based on the monthly data and the second is the case study. The correlation between the monthly percentage occurrence of different sprite types (columns, carrots and intermediate (including V-shaped sprites, co-existence of columns and carrots)) and monthly variation of the -10ºC temperature height has indicated a negative value (r ∼ -0.41) for columns and a high positive value (r ∼ +0.69) for carrots. Further detailed analysis was performed with the height of -10°C at the time of sprite occurrence. It was found that winter sprites occur when the height of -10°C isotherm is located in a range from 1200 m to 3000 m. When the altitude is small, like 1200 -1400 m, the dominant shape is columnar. When the height of -10°C is increased up to 1800 -3000 m, a new situation takes place; that is, more spectacular shapes like carrots tend to be frequently observed. This point is also confirmed by analyzing the temperature at a particular height of 850 hPa. Carrots tend to occur above a threshold of temperature of 850 hPa (-7°C). We can conclude that charge height as the consequence charge separation caused by vertical temperature variation plays an essential role in determining the spatial forms of sprites. Finally, we discuss the initiation of sprites and sprite morphology, with a reference to the observed facts in this paper.

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Section: Analysis Results (Monthly Basis)mentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Morphology of winter sprites in the Hokuriku area of Japan: Monthly variation and dependence on air temperature

Myokei

Matsudo

Asano

et al. 2009

JAE

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“…[14] In reference to (3) of the conclusion, a Trimpi is easily triggered around the Sea of Japan where there seems to be a tendency for higher percentage of ground flashes to lower positive charge, and positive ground flashes occasionally lower extremely large amounts of charge [Michimoto, 1993]. These thunderstorms are formed over the Sea of Japan, often in or to the rear of fronts.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…[Brook et al, 1982;Takeuti and Nakano, 1983;Michimoto, 1993]. However, in the winter season around Japan, a large number of lightning discharges seem to occur not only in the areas of Sea of Japan, but also Pacific area.…”

Section: Occurrence Rate Of Trimpis In Relation To Lightning Areamentioning

confidence: 99%

Characteristic of subionospheric VLF perturbations associated with winter lightning around Japan

Otsuyama

Manabe

Hayakawa

et al. 2004

Geophysical Research Letters

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The VLF signature of ionospheric perturbations (Trimpis) associated with winter lightning around Japan has been investigated during a three‐month observation (December 2000 to February 2001). The absence of observed optical phenomena (mesospheric optical emissions such as sprites) in the Hokuriku area (Sea of Japan side) indicates that the period was not extremely active in lightning as compared with the previous winter [Hobara et al., 2001]. Based on VLF subionospheric observation at Moshiri (Hokkaido) and Maizuru (near Kyoto) for two VLF transmitter signals (NWC (Australia) and NPM (Hawaii)), we have found the following; (1) Lightning discharges are found not only on the Japan‐Sea side, but also on the Pacific side. Although more lightning was observed on the Pacific side of Japan, the Trimpi occurrence rate is more enhanced over the Sea of Japan. (2) Trimpis tend to occur only when the lightning activity is enhanced. (3) Trimpi occurrence rate shows no particular diurnal variation. (4) There is no significant difference in the Trimpi occurrence rate between + and − CG discharges. (5) The intensity of scattered signal (with respect to the unperturbed wave) is, in most case, ranging from −15 to −25 dB. These characteristics are discussed in terms of meteorological and lightning conditions.

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Large bipolar lightning discharge events in winter thunderstorms in Japan

Yoshida

Ushio

et al. 2014

JGR Atmospheres

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Using a low-frequency lightning location system comprising nine stations, we have observed and analyzed 374 large and bipolar electric field change waveforms that occurred during the winter of 2012-2013. Since the waveforms are different from those produced by any well-studied lightning discharge processes, we refer to these source discharge events using a new name: large bipolar events (LBEs). LBEs can be characterized by the following features: (1) All have the same polarity as negative return stroke. (2) All exhibit a single bipolar pulse with a pulse width around 15 μs and similar positive and negative cycles. (3) All are located on the land along the Japan Sea coast, indicating they are probably associated with high grounded objects. (4) Most LBEs produce very large electric field changes that are even larger than that of positive and negative return strokes. (5) Most LBEs are temporally isolated within several milliseconds but are frequently followed by intracloud discharges after tens of milliseconds. (6) Most LBEs produce a single well-distinguished ionospheric reflection pulse, and the time difference between LBE pulse and the corresponding reflection pulse can be used to calculate ionospheric reflection height. It is speculated that LBE is a type of powerful and transient lightning discharge event produced within a compact region of strong electric field formed when the negative charge layer in thunderclouds is very close to the top of a tall grounded object.

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A Study of Radar Echoes and their Relation to Lightning Discharges of Thunderclouds in the Hokuriku District

Abstract: In the present work, winter thunderclouds and active convective clouds were observed by means of

Cited by 56 publications

References 9 publications

Morphology of winter sprites in the Hokuriku area of Japan: Monthly variation and dependence on air temperature

Morphology of winter sprites in the Hokuriku area of Japan: Monthly variation and dependence on air temperature

Characteristic of subionospheric VLF perturbations associated with winter lightning around Japan

Large bipolar lightning discharge events in winter thunderstorms in Japan

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