Publication:
Microwave radiation associated with stepped leaders of negative cloud-to-ground flashes

dc.citedby5
dc.contributor.authorBaharin S.A.S.en_US
dc.contributor.authorAhmad M.R.en_US
dc.contributor.authorAl-Shaikhli T.R.K.en_US
dc.contributor.authorSidik M.A.B.en_US
dc.contributor.authorSabri M.H.M.en_US
dc.contributor.authorAl-Kahtani A.A.N.en_US
dc.contributor.authorMohammad S.A.en_US
dc.contributor.authorLu G.en_US
dc.contributor.authorZhang H.en_US
dc.contributor.authorCooray V.en_US
dc.contributor.authorid57206727343en_US
dc.contributor.authorid16021287600en_US
dc.contributor.authorid57203802841en_US
dc.contributor.authorid6506871127en_US
dc.contributor.authorid57200560218en_US
dc.contributor.authorid57219739527en_US
dc.contributor.authorid57208018699en_US
dc.contributor.authorid12781228700en_US
dc.contributor.authorid57203311320en_US
dc.contributor.authorid7005428121en_US
dc.date.accessioned2023-05-29T09:37:22Z
dc.date.available2023-05-29T09:37:22Z
dc.date.issued2022
dc.descriptionBandwidth; Clouds; Electrons; Microwave antennas; Microwave sensors; Cloud-to-ground flash; Electron avalanches; Head-on collision; High-frequency radiation; Leadtime; Microwave pulse; Radiation pulse; Stepped leader; Streamer; Very high frequency; Microwaves; cloud to ground lightning; corona; electron; microwave radiationen_US
dc.description.abstractIn this paper, Very-High Frequency (VHF) and microwave radiation pulses associated with stepped leader pulses (conventional breakdown) are examined. A total of 100 stepped leader pulses (SLPs) with the associated 100 quiet periods (QPs) from ten negative cloud-to-ground (CG) flashes within the reversal distance (<8 km) have been analyzed. The QP is defined as the period between two SLPs when no electrical activity within the fast antenna sensor bandwidth was detected. The measurement system is made up of fast antenna (FA) and slow antenna (SA) sensors, a VHF sensor (60 MHz center frequency with 40 MHz bandwidth), and a microwave sensor (0.97 GHz center frequency with 20 MHz bandwidth). The waveforms were sampled at 2.5 GHz (400 ps). The total durations of the SLPs and QPs were 2.648 � 1.152 ?s and 2.708 � 1.670 ?s, respectively. All microwave and VHF radiation waveforms have been detected as clear individual oscillating pulses. The key finding is that the microwave radiation can be classified into three categories based on the total number of detected individual oscillating pulses during the QP. Two microwave pulses detected during the QP (Category 1) are suggested to be associated with the electron avalanche/corona process at the tip of an existing negative leader and a space stem. The VHF pulses associated with the microwave pulses are suggested to be emitted by propagating streamers. On the other hand, a single microwave pulse detected during the QP (Category 2) is suggested to be emitted by the electron avalanche/corona process of a space stem. The VHF pulses associated with the microwave pulse are suggested to be emitted by propagating streamers. In both categories, 70% of the microwave radiation pulses have been observed to precede VHF radiation pulses with an average lead time of 0.848 � 1.336 ?s. The head-on collision of a downward propagating negative streamer and an upward propagating positive streamer (from space stem) emitted significant microwave radiation. A new negative leader was formed when the head-on collision took place. The microwave radiation pulses emitted by the head-on collision process were observed to precede SLPs with an average lead time of 0.423 � 0.378 ?s. Around 80% of the microwave radiation pulses preceded VHF radiation pulses with average lead time of 0.540 � 0.596 ?s. Therefore, microwave and VHF radiation pulses are suggested to be emitted by different processes of the electrical breakdown mechanism. The microwave radiation is emitted by electron avalanche/corona/head-on collision while the VHF radiation is emitted by propagating streamers. � 2022en_US
dc.description.natureFinalen_US
dc.identifier.ArtNo106091
dc.identifier.doi10.1016/j.atmosres.2022.106091
dc.identifier.scopus2-s2.0-85124809503
dc.identifier.urihttps://www.scopus.com/inward/record.uri?eid=2-s2.0-85124809503&doi=10.1016%2fj.atmosres.2022.106091&partnerID=40&md5=92cee0884a6ff97d5e7b5c9e35448249
dc.identifier.urihttps://irepository.uniten.edu.my/handle/123456789/26867
dc.identifier.volume270
dc.publisherElsevier Ltden_US
dc.sourceScopus
dc.sourcetitleAtmospheric Research
dc.titleMicrowave radiation associated with stepped leaders of negative cloud-to-ground flashesen_US
dc.typeArticleen_US
dspace.entity.typePublication
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