On the basis of conducting simultaneous observations of cumulonimbi using the X-band radar, and photogrammetry, several cases of cumulonimbus initiations were observed during the mid-summer days from 2010 to 2011 in the southern Kanto region of Japan. The relationship between the maximum growing speed and the maximum height of 40 turrets was almost linear. The average maximum growing speed was 7 m/s. Turrets were categorized into two groups based on their growing speed, relative to this value. The first, named the “inactive” group, consists of turrets that have a relatively low growing speed with a maximum growing speed that is less than 8.5 m/s, and reach up to 8 km AGL. Another group is the “active” group, in which the turrets develop vertically (10 km or more AGL) with a larger maximum growing speed (> 8.5 m/s). In the active group, some turrets grew with a maximum growing speed that was greater than 15 m/s and had a maximum height that was recorded as greater than 10 or 15 km AGL. The turrets that developed over the Boso Peninsula, Japan, during the observation period indicated that the generation area moved northward as time progressed and turrets eventually developed in the northern regions of the Boso Peninsula.
在利用x波段雷达和摄影测量同时观测积雨云的基础上，对2010 - 2011年日本关东地区南部仲夏日积雨云的起爆现象进行了观测。40炮塔的最大生长速度与最大高度之间几乎呈线性关系。平均最高生长速度为7 m/s。根据相对于这个值的增长速度，炮塔被分为两组。第一类被称为“非活动”组，由生长速度相对较低的炮塔组成，最大生长速度小于8.5 m/s，最高可达8 km AGL。另一组是“主动”组，其中炮塔垂直发展(10公里或更高的AGL)，最大生长速度较大(> 8.5米/秒)。在活跃组中，部分炮塔的最大生长速度大于15 m/s，最大高度大于10或15 km AGL。观测期间在日本博索半岛上空形成的炮塔表明，随着时间的推移，产生区向北移动，最终在博索半岛北部地区形成了炮塔。
{"title":"Relationship between Growing Speed and Turret Development","authors":"F. Kobayashi, Akihito Katsura, Takumi Ookubo","doi":"10.1541/jae.38.1","DOIUrl":"https://doi.org/10.1541/jae.38.1","url":null,"abstract":"On the basis of conducting simultaneous observations of cumulonimbi using the X-band radar, and photogrammetry, several cases of cumulonimbus initiations were observed during the mid-summer days from 2010 to 2011 in the southern Kanto region of Japan. The relationship between the maximum growing speed and the maximum height of 40 turrets was almost linear. The average maximum growing speed was 7 m/s. Turrets were categorized into two groups based on their growing speed, relative to this value. The first, named the “inactive” group, consists of turrets that have a relatively low growing speed with a maximum growing speed that is less than 8.5 m/s, and reach up to 8 km AGL. Another group is the “active” group, in which the turrets develop vertically (10 km or more AGL) with a larger maximum growing speed (> 8.5 m/s). In the active group, some turrets grew with a maximum growing speed that was greater than 15 m/s and had a maximum height that was recorded as greater than 10 or 15 km AGL. The turrets that developed over the Boso Peninsula, Japan, during the observation period indicated that the generation area moved northward as time progressed and turrets eventually developed in the northern regions of the Boso Peninsula.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"149 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":"123318296","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}
Yutaka Konishi, T. Takeuti, Shou Inoue, T. Hashimoto, N. Takagi, Y. Katsuragi
{"title":"On a two dimensional simulation model of lightning stepped leader considering its fractalcharacteristics","authors":"Yutaka Konishi, T. Takeuti, Shou Inoue, T. Hashimoto, N. Takagi, Y. Katsuragi","doi":"10.1541/JAE.16.29","DOIUrl":"https://doi.org/10.1541/JAE.16.29","url":null,"abstract":"","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"272 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":"123418247","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 review of the effect of geomagnetic storms on very low frequency (VLF) waves (whistlers and emissions) at low latitudes is presented, based on the spectral analysis of the storm-time VLF data collected over a period of about four decades at our low latitude ground-based Indian stations. The review begins with an introduction about the characteristics of whistlers and VLF emissions and the importance of storm-time VLF events for the developments of our theoretical knowledge in plasma physics. This is followed by four different sections (2-5) in order to understand and explain the physics of VLF events observed at low latitudes during magnetic storms. All aspects of whistler duct and geomagnetic activity are described in section 2 whereas section 3 deals with VLF wave (whistlers and emissions) activity and whistler dispersion. Section 4 presents method of analysis of whistler duct alongwith duct lifetime and VLF emission source used in the spectral analysis of storm-time VLF data reported in the present paper. Section 5 describes in brief the experimental setup used in recording of VLF data at our Indian ground stations with a presentation of some selected storm-time whistlers and emissions alongwith their detailed spectral analysis of the observed salient features. Spectral analyses of the storm-time whistlers and emissions using VLF data from our Indian stations have provided the following results (section 6): mid/high latitude emissions generated in the equatorial region of higher 𝐿 -values through the process of Doppler-shifted cyclotron resonance mechanism and propagated along the higher field lines in different ducts formed by disturbances during magnetic storm and after exiting from the ducts, they penetrated the ionosphere and are trapped in Earth-ionosphere waveguide and after propagating in the waveguide are thus recorded at low latitude ground stations. (3) The increased intensity of whistler and emission activities during magnetic storm periods are due to the formation of additional ducts by the enhanced flux of energetic electrons during magnetic storm periods. along with their dispersion analysis. The dispersion analysis of the storm-time whistlers observed at mentioned Indian stations, shows, that unusual high dispersion whistlers are registered during magnetic storm periods and their dispersions ranges from about 15 - 250 s 1/2 . From the dispersion analysis of these observed storm-time high dispersion whistlers using Dowder-Allcock method (Dowden and Allcock, 1971) and curve-fitting technique of Tarcsai (Tarcsai, 1975), we find that these whistlers have propagated along the higher geomagnetic field lines in different ducts corresponding to 𝐿 -values of 2.88 to 6.52. Hence it may be inferred that storm-time whistlers recorded at low latitudes belong to mid/high latitudes and these whistlers may have propagated in different ducts along higher 𝐿 -values and after exiting from ducts, they penetrated the ionosphere and are trappe
。本文基于对印度低纬度地面站近40年来收集的风暴时间甚低频(VLF)数据的频谱分析，综述了地磁风暴对低纬度地区甚低频(VLF)波(哨声和辐射)的影响。本文首先介绍了口哨和甚低频辐射的特性，以及风暴时甚高频事件对等离子体物理理论知识发展的重要性。接下来是四个不同的部分(2-5)，以便理解和解释磁暴期间在低纬度观测到的VLF事件的物理现象。第2节描述了哨声管道和地磁活动的所有方面，而第3节处理VLF波(哨声和发射)活动和哨声弥散。第4节介绍了在本文报道的风暴时间VLF数据的光谱分析中使用的口哨风管、风管寿命和VLF发射源的分析方法。第5节简要介绍了在我们的印度地面站记录VLF数据所使用的实验装置，并介绍了一些选定的风暴时间哨子和发射，以及对观测到的显著特征的详细光谱分析。利用我们印度站点的VLF数据对风暴时哨声和排放物进行光谱分析，得出以下结果(第6节):在高𝐿-值的赤道地区，通过多普勒偏移回旋共振机制产生的中高纬度辐射，在磁暴扰动形成的不同管道中沿较高场线传播，从管道中出来后，穿透电离层，被困在地球-电离层波导中，在波导中传播后，被低纬度地面站记录。(3)磁暴期间哨声和发射活动强度的增加是由于高能电子通量的增强在磁暴期间形成了额外的管道。以及他们的分散分析。对上述印度站点观测到的风暴时哨子的色散分析表明，在磁暴期间记录到不寻常的高色散哨子，其色散范围约为15 - 250 s /2。利用Dowder-Allcock方法(Dowden and Allcock, 1971)和Tarcsai曲线拟合技术对这些观测到的风暴时高色散哨子进行色散分析，我们发现这些哨子在𝐿-值为2.88 ~ 6.52的不同管道中沿较高的地磁场线传播。因此可以推断，低纬度记录的风暴时间哨声属于中高纬度地区，这些哨声可能沿着较高的𝐿值在不同的管道中传播，从管道中出来后，它们穿过电离层并被困在地球电离层波导中，然后在我们低纬度印度地面站接收到的波导中传播。在波导入口处的波法向角(位于0.2 - 2.3 0范围内)使得它们向赤道传播，并在低纬度的印度地面站接收(Singh等人，2008,2009,2010,2011)。
{"title":"Effect of geomagnetic storms on VLF waves at low latitudes based on the analysis of whistlers and VLF emissions observed at Indian ground stations: A Review","authors":"K. K. Singh, A. P. Mishra","doi":"10.1541/jae.38.67","DOIUrl":"https://doi.org/10.1541/jae.38.67","url":null,"abstract":". A review of the effect of geomagnetic storms on very low frequency (VLF) waves (whistlers and emissions) at low latitudes is presented, based on the spectral analysis of the storm-time VLF data collected over a period of about four decades at our low latitude ground-based Indian stations. The review begins with an introduction about the characteristics of whistlers and VLF emissions and the importance of storm-time VLF events for the developments of our theoretical knowledge in plasma physics. This is followed by four different sections (2-5) in order to understand and explain the physics of VLF events observed at low latitudes during magnetic storms. All aspects of whistler duct and geomagnetic activity are described in section 2 whereas section 3 deals with VLF wave (whistlers and emissions) activity and whistler dispersion. Section 4 presents method of analysis of whistler duct alongwith duct lifetime and VLF emission source used in the spectral analysis of storm-time VLF data reported in the present paper. Section 5 describes in brief the experimental setup used in recording of VLF data at our Indian ground stations with a presentation of some selected storm-time whistlers and emissions alongwith their detailed spectral analysis of the observed salient features. Spectral analyses of the storm-time whistlers and emissions using VLF data from our Indian stations have provided the following results (section 6): mid/high latitude emissions generated in the equatorial region of higher 𝐿 -values through the process of Doppler-shifted cyclotron resonance mechanism and propagated along the higher field lines in different ducts formed by disturbances during magnetic storm and after exiting from the ducts, they penetrated the ionosphere and are trapped in Earth-ionosphere waveguide and after propagating in the waveguide are thus recorded at low latitude ground stations. (3) The increased intensity of whistler and emission activities during magnetic storm periods are due to the formation of additional ducts by the enhanced flux of energetic electrons during magnetic storm periods. along with their dispersion analysis. The dispersion analysis of the storm-time whistlers observed at mentioned Indian stations, shows, that unusual high dispersion whistlers are registered during magnetic storm periods and their dispersions ranges from about 15 - 250 s 1/2 . From the dispersion analysis of these observed storm-time high dispersion whistlers using Dowder-Allcock method (Dowden and Allcock, 1971) and curve-fitting technique of Tarcsai (Tarcsai, 1975), we find that these whistlers have propagated along the higher geomagnetic field lines in different ducts corresponding to 𝐿 -values of 2.88 to 6.52. Hence it may be inferred that storm-time whistlers recorded at low latitudes belong to mid/high latitudes and these whistlers may have propagated in different ducts along higher 𝐿 -values and after exiting from ducts, they penetrated the ionosphere and are trappe","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"30 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":"122951589","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}
This paper was intended to find out any relation between anomalous lineof-sight propagation on the very high frequency (VHF) band and occurrences of earthquakes near the VHF propagation paths. After the stochastic consideration, it was found out that earthquakes associated with anomalous propagation were characterized by relatively large magnitude earthquakes, and relatively near distances from epicenters. Moreover, the authors investigated the relation between average wind speed on the earth’s surface and anomalous line-of-sight propagation in VHF band. As a result, we can obtain the high probability which indicates strong relation between the anomalous propagation and occurrences of earthquakes by considering the average wind speed of the earth’s surface.
{"title":"Statistical relation among earthquakes, average wind speed on the earth's surface, and anomalous propagation of broadcasting waves in the line-of-sight VHF band","authors":"K. Tanigawa, K. Motojima, N. Haga","doi":"10.1541/JAE.37.11","DOIUrl":"https://doi.org/10.1541/JAE.37.11","url":null,"abstract":"This paper was intended to find out any relation between anomalous lineof-sight propagation on the very high frequency (VHF) band and occurrences of earthquakes near the VHF propagation paths. After the stochastic consideration, it was found out that earthquakes associated with anomalous propagation were characterized by relatively large magnitude earthquakes, and relatively near distances from epicenters. Moreover, the authors investigated the relation between average wind speed on the earth’s surface and anomalous line-of-sight propagation in VHF band. As a result, we can obtain the high probability which indicates strong relation between the anomalous propagation and occurrences of earthquakes by considering the average wind speed of the earth’s surface.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"8 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":"125230336","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}
It is well known that single lightning flash storm (SLFS, Ippatsurai in Japanese) is sometimes observed Hokuriku area in winter Japan. However, the frequency and seasonal variation of SLFS are not evaluated quantitatively over the whole of Japan. We investigate the variability of SLFS by using human observations at weather station and electromagnetic observations over Japan from December 2009 to November 2011 for 3 years by Japan Meteorological Agency. As a result, it is confirmed that the higher occurrences of SLFS are concentrated on the Hokuriku coastal area in winter. Additionally, SLFS is also highly observed in Kuroshio extension region in winter and with scattered distribution over the western Japan in summer.
{"title":"Frequency and seasonal variation of single lightning flash storm, ″Ippatsurai″, in Japan","authors":"S. Hayashi, Chizuru Marui","doi":"10.1541/JAE.36.13","DOIUrl":"https://doi.org/10.1541/JAE.36.13","url":null,"abstract":"It is well known that single lightning flash storm (SLFS, Ippatsurai in Japanese) is sometimes observed Hokuriku area in winter Japan. However, the frequency and seasonal variation of SLFS are not evaluated quantitatively over the whole of Japan. We investigate the variability of SLFS by using human observations at weather station and electromagnetic observations over Japan from December 2009 to November 2011 for 3 years by Japan Meteorological Agency. As a result, it is confirmed that the higher occurrences of SLFS are concentrated on the Hokuriku coastal area in winter. Additionally, SLFS is also highly observed in Kuroshio extension region in winter and with scattered distribution over the western Japan in summer.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"10 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":"126153344","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. Myokei, Y. Matsudo, T. Asano, M. Sekiguchi, Tomoyuki Suzuki, Y. Hobara, M. Hayakawa
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.
{"title":"Morphology of winter sprites in the Hokuriku area of Japan : Monthly variation and dependence on air temperature","authors":"K. Myokei, Y. Matsudo, T. Asano, M. Sekiguchi, Tomoyuki Suzuki, Y. Hobara, M. Hayakawa","doi":"10.1541/JAE.29.23","DOIUrl":"https://doi.org/10.1541/JAE.29.23","url":null,"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.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"29 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":"129274300","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. Nakamura, V. Korepanov, Y. Kasahara, Y. Hobara, M. Hayakawa
One major candidate of lithosphere-atmosphere-ionosphere (LAI) coupling mechanism is through atmospheric oscillations triggered near Earth’s surface due to some pre-earthquake (EQ) effect, and this channel has been extensively proved by using meteorological disturbances much more easily treated than pre-EQ effects (Korepanov et al., 2009). In the present paper this channel is challengingly studied, for the first time, for pre-EQ phenomena, and we take a rather strong EQ named Niigata-chuetsu EQ on 23 October, 2004 (with magnitude of 6.8 and with depth of 13 km) for which we already know that the ionospheric perturbation did take place prior to the EQ (Hayakawa et al., 2006). In this paper the LAI coupling has been intensively studied by means of coordinated observational data (surface atmospheric pressure data as an indicator of atmospheric gravity waves (AGWs), our own subionospheric VLF/LF data as a measure of ionospheric perturbations and the ground-based ULF data as a measure to monitor the modulation in the ionospheric dynamic region). The wavelet analyses for these parameters in different spatial regions have all indicated the enhancements of fluctuations in the wave frequency of 10 ~ 100 min (in the frequency range of AGWs). The correlation of wavelet spectra between the atmospheric pressure and VLF/LF amplitude has yielded a high value with the delay of a few hours, while there is nearly no distinct delay of the wavelet spectra between the ionospheric perturbation and the ground-based ULF fluctuation. These observational facts are compared with the theoretical estimation of AGW hypothesis, which may provide a convincing support to the AGW channel of the LAI coupling.
岩石圈-大气-电离层(LAI)耦合机制的一个主要候选机制是通过一些地震前(EQ)效应在地球表面附近触发的大气振荡，这一通道已经通过使用比地震前(EQ)效应更容易处理的气象扰动得到了广泛的证明(Korepanov等，2009)。在本文中，我们首次对前EQ现象进行了具有挑战性的研究，并在2004年10月23日采用了一个相当强的EQ，名为Niigata-chuetsu EQ(震级为6.8，深度为13 km)，我们已经知道电离层扰动确实发生在EQ之前(Hayakawa et al.， 2006)。本文通过协调观测资料(地表大气压力资料作为大气重力波(AGWs)的指标，我们自己的亚层VLF/LF资料作为电离层扰动的测量，以及地面ULF资料作为电离层动力区调制的监测)对LAI耦合进行了深入研究。对这些参数在不同空间区域的小波分析均表明，在10 ~ 100 min (agw频率范围内)波浪频率波动增强。大气压力与极低频/极低频幅值之间的小波谱相关性较高，延迟数小时，而电离层扰动与地面极低频波动之间的小波谱几乎没有明显的延迟。这些观测事实与AGW假设的理论估计进行了比较，为LAI耦合的AGW通道提供了令人信服的支持。
{"title":"An evidence on the lithosphere-ionosphere coupling in terms of atmospheric gravity waves on the basis of a combined analysis of surface pressure, ionospheric perturbations and ground-based ULF variations","authors":"T. Nakamura, V. Korepanov, Y. Kasahara, Y. Hobara, M. Hayakawa","doi":"10.1541/JAE.33.53","DOIUrl":"https://doi.org/10.1541/JAE.33.53","url":null,"abstract":"One major candidate of lithosphere-atmosphere-ionosphere (LAI) coupling mechanism is through atmospheric oscillations triggered near Earth’s surface due to some pre-earthquake (EQ) effect, and this channel has been extensively proved by using meteorological disturbances much more easily treated than pre-EQ effects (Korepanov et al., 2009). In the present paper this channel is challengingly studied, for the first time, for pre-EQ phenomena, and we take a rather strong EQ named Niigata-chuetsu EQ on 23 October, 2004 (with magnitude of 6.8 and with depth of 13 km) for which we already know that the ionospheric perturbation did take place prior to the EQ (Hayakawa et al., 2006). In this paper the LAI coupling has been intensively studied by means of coordinated observational data (surface atmospheric pressure data as an indicator of atmospheric gravity waves (AGWs), our own subionospheric VLF/LF data as a measure of ionospheric perturbations and the ground-based ULF data as a measure to monitor the modulation in the ionospheric dynamic region). The wavelet analyses for these parameters in different spatial regions have all indicated the enhancements of fluctuations in the wave frequency of 10 ~ 100 min (in the frequency range of AGWs). The correlation of wavelet spectra between the atmospheric pressure and VLF/LF amplitude has yielded a high value with the delay of a few hours, while there is nearly no distinct delay of the wavelet spectra between the ionospheric perturbation and the ground-based ULF fluctuation. These observational facts are compared with the theoretical estimation of AGW hypothesis, which may provide a convincing support to the AGW channel of the LAI coupling.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"173 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":"133851291","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}
. In order to make a prediction of earthquakes, we have to find out any relationship between electromagnetic phenomena and earthquakes. We have been observed VHF radio waves that propagate from line-of-sight region for several years. During the observation, we noticed some anomalous propagation associated with lightning storms on the VHF band. When strong lightning storms occur, the anomalous propagation sometimes appears on the VHF radio waves. To get more absolute relationship between anomalous propagation and earthquakes, the anomaly associated without earthquakes should be excluded from anomaly data. Therefore, we investigate the relationship between the anomalous propagation on VHF radio waves and occurrences of lightning storms by statistical original method. In this paper, using statistical estimation, we find out strong relationship between the anomalous propagation on the VHF band and occurrences of lightning storms near the wave propagation path.
{"title":"Statistical relation between lightning and anomalous propagation in the line-of-sight VHF band","authors":"Toshitaka Nanjo, N. Haga, K. Motojima, H. Iwasaki","doi":"10.1541/JAE.36.23","DOIUrl":"https://doi.org/10.1541/JAE.36.23","url":null,"abstract":". In order to make a prediction of earthquakes, we have to find out any relationship between electromagnetic phenomena and earthquakes. We have been observed VHF radio waves that propagate from line-of-sight region for several years. During the observation, we noticed some anomalous propagation associated with lightning storms on the VHF band. When strong lightning storms occur, the anomalous propagation sometimes appears on the VHF radio waves. To get more absolute relationship between anomalous propagation and earthquakes, the anomaly associated without earthquakes should be excluded from anomaly data. Therefore, we investigate the relationship between the anomalous propagation on VHF radio waves and occurrences of lightning storms by statistical original method. In this paper, using statistical estimation, we find out strong relationship between the anomalous propagation on the VHF band and occurrences of lightning storms near the wave propagation path.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"289 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":"122693539","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}
Haitao Huang, Daohong Wang, M. Uman, Ting Wu, N. Takagi
We have performed a study on the luminosity waveforms of 13 return strokes (RSs) in 4 rocket triggered lightning flashes recorded by a high-speed optical imaging system LAPOS5 with a time resolution of 35 ns and a spatial resolution of about 2 m. It was found that as the return strokes propagate upward over the bottom 10 m to 26 m of the lightning channels, which is above their initiation heights, on average the RSs optical waveforms decrease their peaks by 41%, lengthen their 20-90% rise times and 100-80% decay times, and change the relative times of the fastest rising points by 0.38 μs, 0.51 μs, and 0.15 μs. We have also estimated the propagation speeds for all the return strokes by using their 20% peak light intensity points and fastest rising points as reference points for time difference measurements, respectively. It was found that the average RS speed obtained with the 20% peak light intensity points (1.11× 108 m/s) is about twice that obtained with the fastest rising points (0.67× 108 m/s). In addition, we found that for different RSs in an individual lightning flash, the RS with faster propagation speed tends to have a less distorted optical waveform at the higher height.
{"title":"Fine progression features of return stroke luminosity at the bottom of rocket-triggered lightning channels","authors":"Haitao Huang, Daohong Wang, M. Uman, Ting Wu, N. Takagi","doi":"10.1541/JAE.39.57","DOIUrl":"https://doi.org/10.1541/JAE.39.57","url":null,"abstract":"We have performed a study on the luminosity waveforms of 13 return strokes (RSs) in 4 rocket triggered lightning flashes recorded by a high-speed optical imaging system LAPOS5 with a time resolution of 35 ns and a spatial resolution of about 2 m. It was found that as the return strokes propagate upward over the bottom 10 m to 26 m of the lightning channels, which is above their initiation heights, on average the RSs optical waveforms decrease their peaks by 41%, lengthen their 20-90% rise times and 100-80% decay times, and change the relative times of the fastest rising points by 0.38 μs, 0.51 μs, and 0.15 μs. We have also estimated the propagation speeds for all the return strokes by using their 20% peak light intensity points and fastest rising points as reference points for time difference measurements, respectively. It was found that the average RS speed obtained with the 20% peak light intensity points (1.11× 108 m/s) is about twice that obtained with the fastest rising points (0.67× 108 m/s). In addition, we found that for different RSs in an individual lightning flash, the RS with faster propagation speed tends to have a less distorted optical waveform at the higher height.","PeriodicalId":274637,"journal":{"name":"Journal of atmospheric electricity","volume":"12 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":"128462569","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. Nishi, Hidemitsu Shinbara, K. Shin, Teruaki Yoshida
{"title":"Observation results of non-line-of sight 77.1 MHz FM radio waves on three different paths for three years","authors":"M. Nishi, Hidemitsu Shinbara, K. Shin, Teruaki Yoshida","doi":"10.1541/JAE.31.11","DOIUrl":"https://doi.org/10.1541/JAE.31.11","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":"127176489","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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