Observation of signals of VLF radio stations and VLF noise during the solar eclipse on March 29, 2006

Effects of the solar eclipse on March 29, 2006 on signals of VLF radio stations, regular radio-noise intensity in the VLF range 0.3–10 kHz, and the number of atmospherics registered in Yakutsk mainly from the western direction are considered. The full lunar shadow zone consistently shaded the daytime section of the radio-signal propagation path from the western coast of Africa to Altai. A multichannel parallel analyzer-recorder (operating in the frequency range 0.47–8.7 kHz), one-point thunderstorm direction-and-range finder (0.3–100 kHz), narrow-sector radio-noise direction finder (0.3–10 kHz), recorder of VLF radio-station signals, and broadband radio-noise recorder (0.3–100 kHz) were used for observations. Time synchronization of the recorder of VLF radio-station signals was carried out with the help of GPS-clocks. The effect was observed in radio-station signals, radio-noise, and number of atmospherics from a direction of (270 ± 20)°, counted from the north clockwise, in the last stage of the eclipse (∼11–12 UT), when the lunar shadow approached the night terminator and crossed the signal propagation path. The effect was manifested through a ∼20% gain of the received signals, ∼40% increase in the number of atmospherics, and radio-station phase changes. The registered effects are similar to those we observed during the eclipse on March 9, 1997. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 84–87, June, 2007.     

Lidar monitoring of an aerosol precursor of seismic activity during the total solar eclipse of March 29, 2006

A decrease in the tectonic aerosol flux during a total solar eclipse was detected for the first time using a backscattering lidar. The experiment was performed in the tunnel of the Baksan Neutrino Observatory, Russian Academy of Sciences, on March 29, 2006 (11:17:30 UT). It was found that the decrease in the aerosol release is 2 h ahead of the decrease in the amplitude of seismic vibrations. The decrease in seismic activity is interpreted as a result of lithosphere bulging at the ridge of the eclipse-induced tidal wave, which arrives at the point of observation with a delay. The increased sensitivity of aerosol release to lithosphere deformation in comparison with a seismograph and the detected advance give grounds to consider the change in the lidar signal as a precursor of the change in seismic activity.     

The search for vulcanoids in the 2008 total solar eclipse

Interior to Mercury’s orbit is a dynamically stable region where a population of small, asteroid-like bodies called Vulcanoids has been hypothesized to reside. The Vulcanoid Zone (VZ) extends inward from about 0.18 au to about 0.08 au. During the Total Solar Eclipse (TSE) in 2008, a search for Vulcanoids was completed. Although no Vulcanoids was detected to a moving object detection limit of V=12.8, the search was far more comprehensive than previous searches.     

Photometry of the solar corona of March 7, 1970

Isophotes obtained by equidensitometry techniques from four exposures of the March 7, 1970 corona are used for derivation of intensity distributions along the equator, poles, streamers and dark ‘gaps’ in the visible corona. The distributions differ from the van de Hulst curves for a maximum corona. The Kodaikanal measures agree well with the NRL measures of the outer corona made from a rocket coronagraph and together provide data from 1·2R_⊙ to 8·0R_⊙ along the solar equator. Radial intensity gradients for different position angles and the Ludendorff parameters obtained, characterize this corona as typical of the solar maximum.     

New measurements with a torsion pendulum during the solar eclipse

During the solar eclipse of 11 July 1991 in Mexico the period of a torsion pendulum was measured in order to reexamine possible anomalies observed in previous experiments of this kind. In our experiment no significant change was found as the relative change in the period associated with the eclipse was less than 2.0×10^–6 (90% confidence). Results were similar to our previous ones made during the eclipse in 1990 in Finland when the Sun was much lower in the horizon. However, two small but distinct shifts were observed in the horizontal position of the pendulum wire which were well correlated with the beginning and the end of the eclipse.     

Paraconic pendulum: Proposal to detect the gravity screening effect during the full solar eclipse

Summary The possibility to detect Allais effect by the paraconic pendulum with the needle and ball suspension is considered. Foucalt force and friction force are estimated with the conclusion to use the ball suspension system for pendulum.     

日环食激发大气声重力波的研究

利用1987年9月23日日环食期间在中国多个测站获得的地面微压波、无线电探空及太阳辐射资料研究了日食激发声重力波的波源机制、波谱特征、地区差异,并与同时进行的电离层探测结果进行了比较。结果表明此次日环食过程中肯定有重力波发生,其周期与太阳直接辐射起伏经历的时间有明显的一致性。不同地方的日食重力波都来自太阳直接辐射变化直接产生的强迫振荡和各地大气层内的浮力振荡。前者的波动周期较长,振幅较大,直接与日食期间太阳辐射的起伏有关;后者的波动周期较短,振幅较小,与各地日食时局地大气层内的稳定度及湿度条件有关。研究中发现由日食引起的太阳直接辐射有两种与重力波激发有关的起伏过程,一种是初亏-复圆阶段的振荡,其周期与各地日食开始时间有关;一种是复圆后的振荡,其周期与各地食分值有关。这两种起伏周期与日食参数的相关系数都在0.99以上。本文在分析日食的太阳辐射和局地大气效应的基础上,提出了相应的声重力波发生的物理机制,并讨论了日食声重力波与同时发生的电离层振荡的关系。针对70年代以来国内外一直未能解决的日食是否激发大气声重力波的问题,本文得到一个简单而重要的结论:早上发生日食的地方有长周期宽频谱的大气声重力波产生,下午发生日食的地方则没有这种波出现。     

Measurements of atmospheric electrical conductivities during the total solar eclipse of 22 July, 2009

The effect of total solar eclipse on atmospheric conductivities has been studied. Continuous measurements of both types of positive and negative electrical conductivities and some meteorological parameters in conjunction with the total solar eclipse of 22 July, 2009 were made from 21 to 23 July, 2009 at Roorkee (29°52′ N, 77°53′ E, 275 m above sea level). Roorkee observed 90% maximum obscurity of eclipse since it was close to the path of totality. The event started from 05:28 AM IST and ended at 07:42 AM IST with the total eclipse at 06:30 AM IST. Considerable increase of both positive and negative conductivities were recorded during the eclipse with respect to those made on any other day. Increase in relative humidity and decrease in temperature were also observed during the period of eclipse.     

A study on excitation of atmospheric gravity waves from annular solar eclipse

Utilizing the data of microbarometric waves on ground level,radiosonde reports and solar radiations obtained from various observation sta-tions in China during the annular solar eclipse on September 23,1987,themechanism of AGWs excited by the eclipse,the spectral characteristics and thelocal differences have been studied,and the results have been compared withthose from the ionospheric sounding at the same time.It turns out that therewere AGWs excited certainly during this annular solar eclipse,their periods areobviously in accordance with the duration of the fluctuation in the direct solarradiation.     

The abnormal influence of the partial solar eclipse on December 24th, 1992, on the time comparisons between atomic clocks

Summary During the partial solar eclipse on Dec. 24th, 1992, time comparisons between atomic clocks were made: direct comparisons between different clocks at one and the same station, clock transport comparisons, GPS comparisons and LOC comparisons. And it is concluded from the observations that solar eclipse exerts an influence on the rate of atomic clocks. Project Supported by the State Science and Technology Commission of China and by the National Natural Foundation of China.     

日全食下城市热环境的变化特征分析

2009年7月22日,我国长江流域能很好地观测到一次千载难逢的日全食现象,且重庆是一个非常好的日全食观测点.作者观测了重庆地区7月21日及22日两天的室外气象数据(太阳辐射,空气温度,相对湿度等),基于实验观测数据,分析和探讨了日全食对室外热环境的影响.日全食当天,室外气温和地表温度随太阳辐射强度的减小而减小,空气温度...     

Feature of the multifractal structure of small-scale ionospheric turbulence during the solar eclipse of August 1, 2008

Using the method of radio sounding of the mid-latitude ionosphere by the satellite signals, we study the multifractal structure of small-scale ionospheric turbulence during a solar eclipse. The measured multipower and generalized multifractal spectra of small-scale ionospheric turbulence at the initial and closing stages of the eclipse turn out to be almost identical on the space radio paths with different orientations. This is indicative of a sufficiently high stability of the nonuniform spatio-temporal distribution of small-scale fluctuations of the ionospheric electron number density under conditions of geophysical disturbances due to global physical processes in the ionospheric plasma during a solar eclipse. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 52, No. 4, pp. 302–306, April 2009.     

1987年9月23日日环食所产生的大气内重力波

在日食期间,月影以超声速移过地球大气而使局部大气冷却。Chimonas和Hines认为大气冷却的结果产生激波,诱发大气重力波。这时在电离层中可检测到TID而在地面上可检测到大气压力变化。虽然在电离层中这种重力波信号很弱,但仍可检测到。地面压力变化发生在日食附近地区,甚至离主食带相当远的地方也可以测到。本文报告了在中国首次直接观测日环食引起地面压力波的检测结果。1987年9月23日日环食期间,位于环食带的乌鲁木齐,太原,徐州,苏州及位于偏食带的北京和贵阳共六个次声观测站用电容式微气压计在我国首次探测到日环食产生的声重力波,其周期为10—60min,振幅为7—20Pa(峰-峰值)。动态谱分析的结果表明,各地的重力波周期都有连续的谱分布,其主周期为40min。此外,各地记录到出现时间不同而周期更长的波,对这些结果本文作了初步计论。     

Mixing layer height and meteorological measurements in Hefei China during the total solar eclipse of 22 July, 2009

Mixing layer height measurements with an elastic-backscattered lidar were carried out in Hefei, China, during the total solar eclipse of 22 July, 2009. The mixing layer height evolution is studied with the observation of changes in near-ground temperature, relative humidity and wind speed. The lidar emits the laser at the wavelengths of 532 and 355 nm, respectively, and obtains the backscattered signal with the resolution of 10 m. The whole eclipse witnessed the mixing layer change similar to that occurring during sunset. The results also show the mixing layer height decreased to 287 m rapidly during the total eclipse within only more than 1 min from the initial 354 m. The entrainment thickness reached the minimum of 43 m in the eclipse, indicating the weakening of the penetrative convection. Thereafter the thickness kept a constant value of 180 m. The temperature in the whole eclipse is uptrend, increasing only by 0.5 °C as a whole. The wind speed decreased and simultaneously the wind direction changed. The wind speed reached its minimum of 2 m/s at the end of the eclipse.