Since 1980, we have detected impulsive noise bursts of seismogen ic emissions at 82 kHz, 1525 Hz and 36Hz by a multipoint detec tion network around Tokyo region and Izu peninsula. In the ear lier times, this system has recorded EM signals prior to several earthquake events. And they have recorded volcanic eruptions on November 15 and 21, 1986 at Mt. Mihara on Ohshima Island, on July 12, 1989 in Itoh Bay at the Izu peninsula region, and since June in 1991 at Mt.Unzen on the Shimabara peninsula. To obtain a clear explanation of the source mechanizum of these emissions, we were progressing the statistical analysis of these emission charac teristics by data of 29 events in the last five years.
{"title":"RESULTS OF STATISTICAL ANALYSIS OF LF SEISMOGENIC EMISSIONS AS PRECURSORS TO THE EARTHQUAKE AND VOLCANIC ERUPTIONS","authors":"T. Yoshino, I. Tomizawa, T. Sugimoto","doi":"10.1541/JAE.12.203","DOIUrl":"https://doi.org/10.1541/JAE.12.203","url":null,"abstract":"Since 1980, we have detected impulsive noise bursts of seismogen ic emissions at 82 kHz, 1525 Hz and 36Hz by a multipoint detec tion network around Tokyo region and Izu peninsula. In the ear lier times, this system has recorded EM signals prior to several earthquake events. And they have recorded volcanic eruptions on November 15 and 21, 1986 at Mt. Mihara on Ohshima Island, on July 12, 1989 in Itoh Bay at the Izu peninsula region, and since June in 1991 at Mt.Unzen on the Shimabara peninsula. To obtain a clear explanation of the source mechanizum of these emissions, we were progressing the statistical analysis of these emission charac teristics by data of 29 events in the last five years.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"104 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131298857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Morimoto, H. Kikuchi, S. Yoshida, T. Ushio, Z. Kawasaki
This paper reviews developments and lightning observations on a small satellite “Maido-1” and its electromagnetic (EM) payload, the very high frequency (VHF) sensor. Maido-1 satellite was launched on January 23, 2009 and injected into the sunsynchronous polar orbit at an altitude of 660 km. A radio frequency receiver was installed on Maido-1 to examine the feasibility of the space-based digital interferometer receiving lightning EM impulses in VHF band. Through the nine months of the operation period of Maido-1, the VHF sensor conducted 158 lightning observations and recorded about 15,000 VHF EM waveforms around the world. The main achievements of the VHF sensor on Maido-1 are 1) functional confirmation of the sensor manufactured by commercial off-theshelf products, 2) validation of the sensor sensitivity designed by the numerical estimation for the attenuation in the propagation path, and 3) verification of the available EM noise environment for the lightning observation on the orbit. Characteristics of pulse duration and pulse pair founded in the recoded waveforms are studied using numerical simulation for a layered ionosphere model. This paper also proposes the estimation considering the ionospheric propagation, and its effectiveness is demonstrated.
{"title":"Lightning observations of a small satellite “Maido-1”","authors":"T. Morimoto, H. Kikuchi, S. Yoshida, T. Ushio, Z. Kawasaki","doi":"10.1541/JAE.36.39","DOIUrl":"https://doi.org/10.1541/JAE.36.39","url":null,"abstract":"This paper reviews developments and lightning observations on a small satellite “Maido-1” and its electromagnetic (EM) payload, the very high frequency (VHF) sensor. Maido-1 satellite was launched on January 23, 2009 and injected into the sunsynchronous polar orbit at an altitude of 660 km. A radio frequency receiver was installed on Maido-1 to examine the feasibility of the space-based digital interferometer receiving lightning EM impulses in VHF band. Through the nine months of the operation period of Maido-1, the VHF sensor conducted 158 lightning observations and recorded about 15,000 VHF EM waveforms around the world. The main achievements of the VHF sensor on Maido-1 are 1) functional confirmation of the sensor manufactured by commercial off-theshelf products, 2) validation of the sensor sensitivity designed by the numerical estimation for the attenuation in the propagation path, and 3) verification of the available EM noise environment for the lightning observation on the orbit. Characteristics of pulse duration and pulse pair founded in the recoded waveforms are studied using numerical simulation for a layered ionosphere model. This paper also proposes the estimation considering the ionospheric propagation, and its effectiveness is demonstrated.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"427 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131758318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The depression (reduction in amplitude) of ULF magnetic field variations of magnetospheric origin is studied at various distances from the epicenter of the strongest earthquake (EQ) which occurred in Japan on March 11, 2011. For this purpose, we have used the ULF data in Japan observed by fluxgate magnetometers at three places located at distances of ~300 km to ~1300 km from the epicenter of the main shock. The period of data analysis is from December 1, 2010 to May 31, 2011. We have found a sharp increase in depression of the horizontal ULF magnetic field component at the frequency of 0.03 0.05 Hz (30-50 mHz) at all of three Japanese observatories (Kakioka, Memambetsu and Kanoya) three days before the first strong foreshock (Mw=7.5) and five days before the main shock (Mw = 9). This peak in depression is found to be several times greater than all previous values, but the depression seems to be most enhanced at Kakioka, the station nearest to the EQ epicenter. So that it is likely that this phenomenon could be a possible precursor to the huge 3.11 EQ.
{"title":"ULF Magnetic Field Depression as a Possible Precursor to the 2011/3.11 Japan Earthquake","authors":"A. Schekotov, E. Fedorov, Y. Hobara, M. Hayakawa","doi":"10.1541/JAE.33.41","DOIUrl":"https://doi.org/10.1541/JAE.33.41","url":null,"abstract":"The depression (reduction in amplitude) of ULF magnetic field variations of magnetospheric origin is studied at various distances from the epicenter of the strongest earthquake (EQ) which occurred in Japan on March 11, 2011. For this purpose, we have used the ULF data in Japan observed by fluxgate magnetometers at three places located at distances of ~300 km to ~1300 km from the epicenter of the main shock. The period of data analysis is from December 1, 2010 to May 31, 2011. We have found a sharp increase in depression of the horizontal ULF magnetic field component at the frequency of 0.03 0.05 Hz (30-50 mHz) at all of three Japanese observatories (Kakioka, Memambetsu and Kanoya) three days before the first strong foreshock (Mw=7.5) and five days before the main shock (Mw = 9). This peak in depression is found to be several times greater than all previous values, but the depression seems to be most enhanced at Kakioka, the station nearest to the EQ epicenter. So that it is likely that this phenomenon could be a possible precursor to the huge 3.11 EQ.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116608583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A special negative cloud-to-ground (-CG) flash imaged by a low frequency lightning mapping system is reported in this paper. This flash initiated at a high altitude of about 11 km. The initiation location is inferred to be the lower edge of the upper positive charge region. Both initial positive and negative leaders had downward propagations, but during the initial 500 ms the negative leader had little development. An important feature of this -CG flash is that it did not start with classic preliminary breakdown (PB) pulses; there were only a few very small and narrow (~1 μs) pulses during the initial 100 ms. The absence of PB pulses was a direct result of the inactive initial negative leader, which was caused by the high initiation altitude. We suggest that lightning flashes, including CG and intracloud flashes, initiating at high altitudes (roughly >10 km) mostly start without classic PB pulses.
{"title":"A negative cloud-to-ground lightning flash initiating at a high altitude and starting without classic preliminary breakdown pulses","authors":"Ting Wu, Daohong Wang, N. Takagi","doi":"10.1541/jae.39.16","DOIUrl":"https://doi.org/10.1541/jae.39.16","url":null,"abstract":"A special negative cloud-to-ground (-CG) flash imaged by a low frequency lightning mapping system is reported in this paper. This flash initiated at a high altitude of about 11 km. The initiation location is inferred to be the lower edge of the upper positive charge region. Both initial positive and negative leaders had downward propagations, but during the initial 500 ms the negative leader had little development. An important feature of this -CG flash is that it did not start with classic preliminary breakdown (PB) pulses; there were only a few very small and narrow (~1 μs) pulses during the initial 100 ms. The absence of PB pulses was a direct result of the inactive initial negative leader, which was caused by the high initiation altitude. We suggest that lightning flashes, including CG and intracloud flashes, initiating at high altitudes (roughly >10 km) mostly start without classic PB pulses.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131988949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Tomita, T. Morimoto, H. Motoyoshi, Y. Nakamura, H. Sakai
. The Ku-band radar reflectivity factors Z at multiple altitudes near the ground are compared with the surface precipitation rate R in the case of snow. R is obtained by the Snow-rain intensity meter, and the types of precipitation are identified using the CMF (Center of Mass Flux Distribution) of the size and fall speed distribution obtained by the optical disdrometer. It is validated that the raindrop constants B and β with Ku-band radar observations give us the information about the characteristics of snow aggregate by comparing them with those of sleets . The results are consistent with X-band radar observations. The bright band is also noticeable in Ku-band.
。对近地面多个高度的ku波段雷达反射率因子Z与积雪情况下的地表降水率R进行了比较。R由雪雨强度计获得，而降水类型则由光学分差仪获得的大小和下落速度分布的CMF (Center of Mass Flux Distribution)来识别。通过与雨夹雪的比较，验证了ku波段雷达观测的雨滴常数B和β能提供雪团的特征信息。结果与x波段雷达观测结果一致。亮带在ku波段也很明显。
{"title":"Z-R relationship of snow on Ku-band radar observations","authors":"K. Tomita, T. Morimoto, H. Motoyoshi, Y. Nakamura, H. Sakai","doi":"10.1541/jae.39.33","DOIUrl":"https://doi.org/10.1541/jae.39.33","url":null,"abstract":". The Ku-band radar reflectivity factors Z at multiple altitudes near the ground are compared with the surface precipitation rate R in the case of snow. R is obtained by the Snow-rain intensity meter, and the types of precipitation are identified using the CMF (Center of Mass Flux Distribution) of the size and fall speed distribution obtained by the optical disdrometer. It is validated that the raindrop constants B and β with Ku-band radar observations give us the information about the characteristics of snow aggregate by comparing them with those of sleets . The results are consistent with X-band radar observations. The bright band is also noticeable in Ku-band.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132696227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Hata, K. Ohta, J. Izutsu, I. Takumi, T. Fujii, Tokiyasu Sato, S. Yahashi, N. Watanabe
{"title":"Development of ULF Band Receiver for Detecting Electromagnetic-Wave Precursor of Earthquakes","authors":"M. Hata, K. Ohta, J. Izutsu, I. Takumi, T. Fujii, Tokiyasu Sato, S. Yahashi, N. Watanabe","doi":"10.1541/JAE.30.13","DOIUrl":"https://doi.org/10.1541/JAE.30.13","url":null,"abstract":"","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132119956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chorus emissions are the most common form of very low frequency (VLF) emissions in the Earth’s magnetosphere which typically consist of a series of rising tones generated near the magnetic equator, excited by energetic electrons injected into the inner magnetosphere. In the present study, observation of chorus emissions recorded at Indian low latitude ground station Jammu (geomag. lat., 19 26 N; L = 1.17) during a geomagnetic quiet period on 24 February, 1999 is reported. The spectral analysis of recorded chorus emissions shows that each chorus element originates from the upper edge of the underlying hiss band. The observed mean chorus element parameters are as follows: lower band frequency fmin = 1.2 kHz, upper band frequency fUB = 1.96 kHz, frequency sweep rate df/dt = 1.14 kHz/s and repetition period T = 2.5 s. To explain the observed dynamic spectra of these chorus emissions, a possible generation mechanism is presented based on the recent nonlinear theory. It is observed that the seeds of chorus emissions grow from the saturation level of the whistler-mode instability at the equator and then propagate away from the equator as a result of a nonlinear growth mechanism that depends on the wave amplitude. On the basis of this theory, frequency sweep rate of chorus emission is computed and compared with that of our experimentally observed values, which shows, in general, a good agreement.
{"title":"Observations of Rising Tone Chorus Emissions at Indian Low Latitude Ground Station and Their Generation Mechanism","authors":"Sanju Singh, K. K. Singh, Ashutosh Kumar Singh","doi":"10.1541/JAE.33","DOIUrl":"https://doi.org/10.1541/JAE.33","url":null,"abstract":"Chorus emissions are the most common form of very low frequency (VLF) emissions in the Earth’s magnetosphere which typically consist of a series of rising tones generated near the magnetic equator, excited by energetic electrons injected into the inner magnetosphere. In the present study, observation of chorus emissions recorded at Indian low latitude ground station Jammu (geomag. lat., 19 26 N; L = 1.17) during a geomagnetic quiet period on 24 February, 1999 is reported. The spectral analysis of recorded chorus emissions shows that each chorus element originates from the upper edge of the underlying hiss band. The observed mean chorus element parameters are as follows: lower band frequency fmin = 1.2 kHz, upper band frequency fUB = 1.96 kHz, frequency sweep rate df/dt = 1.14 kHz/s and repetition period T = 2.5 s. To explain the observed dynamic spectra of these chorus emissions, a possible generation mechanism is presented based on the recent nonlinear theory. It is observed that the seeds of chorus emissions grow from the saturation level of the whistler-mode instability at the equator and then propagate away from the equator as a result of a nonlinear growth mechanism that depends on the wave amplitude. On the basis of this theory, frequency sweep rate of chorus emission is computed and compared with that of our experimentally observed values, which shows, in general, a good agreement.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133739034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Long term statistics of aircraft lightning strikes and thunder days at Komatsu airport","authors":"Tomoyuki Suzuki, Tatsuki Hirano, Yasunari Taniguchi, Takamitsu Kimura","doi":"10.1541/jae.41.1","DOIUrl":"https://doi.org/10.1541/jae.41.1","url":null,"abstract":"","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125873163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daohong Wang, T. Ushio, Z. Kawasaki, K. Matsuura, Y. Shimada, S. Uchida, C. Yamanaka, Y. Izawa, Y. Sonoi, N. Simokura
. To study the possibility of triggering techniques of lightning discharges with a laser plasma, several experiments were carried out with a C0 2 pulse laser and a switching voltage generator. The following results were obtained. Both long straight discharges and zigzag discharges were induced with a laser plasma channel and the strong guiding effect of the laser channel has been confirmed. Laboratory investigation of the necessary condition for initiating and guiding a streamer with a laser plasma channel reveals that, (1) the necessary electric field for initiating a streamer with a laser plasma depends closely on the absorbed energy used to produce laser plasma channels and the minimum electric field is about 200kV/m, and (2) the necessary electric field for guiding a streamer by a laser plasma is lower than that of initiating a streamer and the minimum electric field is about 170kV/m. The simple calculation of the electric field distribution at the top of a grounded tower shows that a laser plasma channel may trigger a lightning discharge from the top of the tower .
{"title":"THE STUDY OF THE POSSIBILITY OF LIGHTNING TRIGGERING BY MEANS OF A LASER","authors":"Daohong Wang, T. Ushio, Z. Kawasaki, K. Matsuura, Y. Shimada, S. Uchida, C. Yamanaka, Y. Izawa, Y. Sonoi, N. Simokura","doi":"10.1541/JAE.14.49","DOIUrl":"https://doi.org/10.1541/JAE.14.49","url":null,"abstract":". To study the possibility of triggering techniques of lightning discharges with a laser plasma, several experiments were carried out with a C0 2 pulse laser and a switching voltage generator. The following results were obtained. Both long straight discharges and zigzag discharges were induced with a laser plasma channel and the strong guiding effect of the laser channel has been confirmed. Laboratory investigation of the necessary condition for initiating and guiding a streamer with a laser plasma channel reveals that, (1) the necessary electric field for initiating a streamer with a laser plasma depends closely on the absorbed energy used to produce laser plasma channels and the minimum electric field is about 200kV/m, and (2) the necessary electric field for guiding a streamer by a laser plasma is lower than that of initiating a streamer and the minimum electric field is about 170kV/m. The simple calculation of the electric field distribution at the top of a grounded tower shows that a laser plasma channel may trigger a lightning discharge from the top of the tower .","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115846109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The connection between meteor showers and VLF atmospheric noise signals","authors":"Y. Reuveni, C. Price, Y. Yair, R. Yaniv","doi":"10.1541/JAE.31.23","DOIUrl":"https://doi.org/10.1541/JAE.31.23","url":null,"abstract":"","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115967320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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