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1.
Summary On the occasion of the total solar eclipse in Viareggio (Italy) measurements of intensity of sky radiation and polarization have been carried out at 90 degrees vertical distance from the sun. UV-, green- and red-filters have been used. The results showed a diminution of the intensity during the eclipse of about 3 powers of ten. The sky brightness in the point 90 degrees distant during the total eclipse was similar to the brightness when sun is 7 degrees below the horizon. About one minute before the total eclipse the degree of polarization diminuished to zero. — Furthermore photos of nearly the total sky were made using two cameras with wide angle lenses. 相似文献
2.
Ground-based observations of the spectral sky radiance within the totality region during a total solar eclipse are of significant interest because the contribution from direct and single scattered light from the solar disk is eliminated. In the present paper, we develop a numerical model of the spectral sky radiance during totality, evaluate the contribution of double scattered sunlight to the sky radiance at totality and compare it to solar corona emissions. The results show that the single scattered coronal light is the major contaminant in ground-based observations of the corona, opposite to what was believed before. For observation directions outside the corona the double scattered sun radiation dominates over the single scattered coronal light. 相似文献
3.
XueWu Cheng Yong Yang ZeLong Wang FaQuan Li GuoTao Yang ZhengYu Zhao Wei Gong JiHong Wang Xiong Hu Xin Lin XiaoCheng Wu ShaLei Song ShunSheng Gong 《中国科学:地球科学(英文版)》2016,59(2):418-424
During the total solar eclipse on July 22, 2009 in Wuhan, the joint observation test of Na layer and ionosphere was conducted by using the daytime observation atmospheric lidar and the GPS ionosphere detector. The results show that the full width at half maximum (FWHM) of Na layer density slightly narrowed during the total solar eclipse and broadened after the eclipse, while the height of Na peak slightly decreased in the eclipse and increased after the eclipse. These implying that Na layer changes reflect the rapid process of sunrise and sunset. The ionosphere total electron content (TEC) and the sky background light noise also presented an obvious fluctuation characteristic with the changes of solar irradiation during the process of total solar eclipse. The difference lies in that the changes of FWHM of Na layer atoms are much slower than that of ionosphere, the reason for this might be that the Na layer, after being disturbed by the total solar eclipse, will generate a series of complicated photochemical reactions and momentum transport processes, and then recombine the Na atoms. The Na atoms to be detected by the lidar need a lag process, which rightly conforms to the theoretical simulated results. 相似文献
4.
《Journal of Atmospheric and Solar》2008,70(6):836-853
An annular eclipse occurred over Europe in the morning hours of 3 October 2005. The well-defined obscuration function of the solar radiation during the eclipse provided a good opportunity to study the ionospheric/thermospheric response to solar radiation changes. Since the peak electron density behavior of the ionospheric F2 layer follows the local balance of plasma production, loss and transport, the ionospheric plasma redistribution processes significantly affect the shape of the electron density profile. These processes are discussed here based on a comparison of vertical incidence sounding (VS) and vertical total electron content (TEC) data above-selected ionosonde stations in Europe. The equivalent slab thickness, derived with a time resolution of 10 min, provides relatively good information on the variation of the electron density profile during the eclipse. The computations reveal an increased width of the ionosphere around the maximum phase. As indicated by the available measurements over Spain, the photo production is significantly reduced during the event leading to a slower increase of the total ionization in comparison with the neighboring days. The supersonic motion of the Moon's cool shadow through the atmosphere may generate atmospheric gravity waves that propagate upward and are detectable as traveling ionospheric disturbances at ionospheric heights. High-frequency (HF) Doppler shift spectrograms were recorded during the eclipse showing a distinct disturbance along the eclipse path. Whereas the ionosonde measurements at the Ebro station/Spain in the vicinity of the eclipse path reveal the origin of the wave activity in the lower thermosphere below about 180 km altitude, the similar observations at Pruhonice/Czech Republic provide arguments to localize the origin of the abnormal waves in the middle atmosphere well below the ionospheric heights. Although ionosonde and HF Doppler measurements show enhanced wave activity, the TEC data analysis does not, which is an indication that the wave amplitudes are too small for detecting them via this interpolation method. The total ionization reduces up to about 30% during the event. A comparison with similar observations from the solar eclipse of 11 August 1999 revealed a quite different ionospheric behavior at different latitudes, a fact that needs further investigation. 相似文献
5.
E.F. Nymphas M.O. Adeniyi M.A. Ayoola E.O. Oladiran 《Journal of Atmospheric and Solar》2009,71(12):1245-1253
The total solar eclipse of 29 March, 2006 which was visible at Ibadan (7.55°N, 4.56°E), south-western Nigeria was utilized to document atmospheric surface-layer effects of the eclipse for the first time in Nigeria. The meteorological parameters measured are global radiation, net radiation, wind speed (at different heights), atmospheric pressure and soil temperature (5, 10 and 30 cm), moisture and heat flux and rainfall. The results revealed remarkable dynamic atmospheric effects. The observations showed that the incoming solar radiation, net radiation and air temperature were significantly affected.There was an upsurge of wind speed just before the first contact of the eclipse followed by a very sharp decrease in wind speed due to the cooling and stabilization of the atmospheric boundary layer. The atmospheric pressure lags the eclipse maximum by 1 h 30 min, while the soil temperature at 5 and 10 cm remain constant during the maximum phase of the eclipse. 相似文献
6.
Swept-frequency (1/10 MHz) ionosonde measurements were made at Helston, Cornwall (50°06N, 5°18W) during the total solar eclipse on August 11, 1999. Soundings were made every three minutes. We present a method for estimating the percentage of the ionising solar radiation which remains unobscured at any time during the eclipse by comparing the variation of the ionospheric E-layer with the behaviour of the layer during a control day. Application to the ionosonde date for 11 August, 1999, shows that the flux of solar ionising radiation fell to a minimum of 25±2% of the value before and after the eclipse. For comparison, the same technique was also applied to measurements made during the total solar eclipse of 9 July, 1945, at Sörmjöle (63°68N, 20°20E) and yielded a corresponding minimum of 16 ± 2%. Therefore the method can detect variations in the fraction of solar emissions that originate from the unobscured corona and chromosphere. We discuss the differences between these two eclipses in terms of the nature of the eclipse, short-term fluctuations, the sunspot cycle and the recently-discovered long-term change in the coronal magnetic field. 相似文献
7.
M. Antón A. Serrano M.L. Cancillo J.M. Vaquero J.M. Vilaplana 《Journal of Atmospheric and Solar》2010,72(9-10):789-793
The ground track of the annular eclipse of 3 October 2005 crossed the Iberian Peninsula. The main objective of this work was to analyze the variability of the solar irradiance and the total ozone column during the course of this event at El Arenosillo (Southwestern Spain). For achieving this goal, two Kipp & Zonen broadband radiometers (one for measuring total solar irradiance and other for measuring ultraviolet erythemal solar irradiance), one NILU-UV multi-band instrument and one Brewer spectroradiometer were used in this work. Total irradiance (310–2800 nm), and ultraviolet erythemal radiation (UVER) were recorded at a high frequency of 5 s, showing a strong reduction (higher than 80%) of the irradiance at the maximum solar obscuration which was of 79.6%. The irradiance decrease during the course of the eclipse was positively correlated with the percentage of eclipse obscuration, showing a very high agreement (R2～0.99). The irradiance recorded at selected wavelengths from the NILU-UV instrument shows a more pronounced decrease in the UV irradiance at the lower wavelengths during the solar eclipse. Finally, the evolution of the total ozone column (TOC) derived from Brewer and NILU instruments during the eclipse presented an opposite behavior: while the Brewer derived TOC values increase about 15 DU, the NILU derived TOC values decrease about 11 DU. This opposite behavior is mainly related to an artifact in the spectral irradiances recorded by the two instruments. 相似文献
8.
V. I. Skomorovsky V. D. Trifonov G. P. Mashinch Yu. S. Zaiganova V. G. Fainshtein G. I. Kushtal’ S. A. Chuprakov 《Geomagnetism and Aeronomy》2011,51(8):1063-1077
A new telescope has been created to investigate the solar corona during eclipses. One lens simultaneously forms three corona
images occurring as coronal radiation passes through three polarizers with transmission directions rotated 0°, 60°, and 120°
relative to the selected direction; in addition, one image is formed without the polarizer. The telescope was used for solar
corona observation during the eclipse of August 1, 2008. We obtained the distributions of polarization brightness, K corona
brightness, degree of K corona polarization, and total degree of polarization as well as polarization directions depending
on the latitude and radius in the sky plane. Radial distributions of the electron density depending on latitude were calculated.
The coronal plasma temperature was determined for different corona structures under the assumption of hydrostatic equilibrium. 相似文献
9.
“年月日日环食期间太阳辐射和大气重力波的分析研究”课题组 《地球物理学报》1990,33(4):399-407
本文通过对1987年9月23日日环食期间太阳辐射和地面气象要素等实测资料的分析,指出了在日环食过程中太阳辐射和地面气象要素等的变化,也叙述了日食期间地面臭氧含量的变化;第一次在国内测得了由日食引起的大气重力波,进而讨论了大气重力波的若干特性. 相似文献
10.
Using observations with a high angular resolution of ??1??, we reveal a cyclotron radiation source with a ring-shaped structure of the image. The source is located in the solar corona above the main spot of the NOAA 11140 active region. Observations were carried out during the solar eclipse of January 4, 2011, using two RT-32 radio telescopes that operated at wavelengths of 3.5, 6.2, and 13 cm and registered Stokes parameters I and V. The features of the structure are interpreted within the known theory of the cyclotron radio radiation of hot coronal plasma (2?C4 MK) in the presence of the strong magnetic field of the sunspot (??3 kG). 相似文献
11.
Xinmiao Zhang Zhengyu Zhao Yuannong Zhang Chen Zhou 《Journal of Atmospheric and Solar》2010,72(11-12):869-875
An exceptionally long total solar eclipse occurred over the Yangtze River Basin in the mid-latitudes of China on 22 July 2009. The moon’s umbral shadow crossed through the ionospheric equatorial anomaly region. During the solar eclipse, new ionospheric behaviors were observed using a multi-station sounding approach. These new phenomena include: (1) visible Doppler spreading of F layer echoes at multiple group distances during the solar eclipse period, (2) strong ionospheric response near the peak of the northern equatorial anomaly crest and (3) synchronous oscillations in the Es and F layer during the recovery phase of the solar eclipse. 相似文献
12.
Dieter Lorenz 《Pure and Applied Geophysics》1962,53(1):143-158
Zusammenfassung Es wird über eine photographische Methode berichtet, die gestattet, die Verteilung der Himmelsstrahlung zu bestimmen. Der Himmel wird mit einer Weitwinkelkamera photographiert und die Aufnahmen werden mit einem Photometer ausgewertet. Über einen Graukeil, der auf das gleiche filmmaterial aufbelichtet und mit den Aufnahmen zusammen entwickelt wird, lassen sich die mit dem Photometer ermittelten Schwärzungswerte in (relative) Intensitätswerte der Himmelsstrahlung umrechnen. Der durch das Photoobjektiv bedingte Helligkeitsabfall von der Bildmitte aus nach den Bildrändern zu wird experimentell ermittelt und als Korrektur an den Meßwerten angebracht. Die Intensitätsverteilung der Himmelsstrahlung während der totalen Sonnenfinsternis am 15. Februar 1961 in Viareggio (Norditalien), am Abend zuvor und am Folgetag wird wiedergegeben und diskutiert. Während der totalen Verfinsterung spiegelt sich insbesondere die Wanderung des Mondschattens relativ zum Beobachtungsort in den Darstellungen wieder. Während der partiellen Verfinsterung ist dagegen die relative Helligkeitsverteilung praktisch die gleiche wie bei unverfinsterter Sonne.
Summary A photographic method is described which permits to determinate the distribution of the sky radiation. The sky is photographed by a wide angle camera and the resulting pictures are evaluated by a photometer. A photometric step wedge copied on a film of the same type and number is developed together with the pictures. Then the density values measured by the photometer can be transformed into (relative) intensity values of the sky radiation. The decrease in brightness from the centre of the picture to the rim caused by the photographic lens is determined experimentally and is taken into account as a correction to the density values. The distribution of intensity of the sky radiation in Viareggio (North Italy) during the total eclipse of the sun on the 15th of february 1961, on the previous evening and on the following day are shown and discussed. During the total eclipse especially the migration of the moon's shadow in relation to the observation point is clearly defined. During the partial eclipse, however, practically the same relative distribution of sky radiation is found as without eclipse.相似文献
13.
Population of Daphnia carinata exposed to different times on the day showed sharp inhibition of reproduction (measured different life table data) on the day of solar eclipse as compared to pre- and post-eclipse days. Sudden fall of water temperature and abrupt change to darkness as prevailed during the solar eclipse were responsible for inhibition of reproduction in Daphnia carinata. Cold and dark induced reproductive inhibition was also confirmed in a simulated experiment mimicing eclipse reduction in light and temperature. 相似文献
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Summary The article first describes in chronological order the observations on the propagation of radio waves during the solar eclipses, and the development of the conflicting results on the similar transmissions of radio signals. The general theory of the absorption of radio waves in the ionosphere is briefly described and therefrom a method is derived to estimate the variation of the absorption of obliquely incident radio waves during a solar eclipse.The variation of field-strength can be studied in terms of the relationship between the vertical incident equivalent frequency of the signals and the critical frequencies of the ionospheric layers at the regions of reflection. The total absorption of radio waves consists of the non-deviative absorption in theD region and the deviative absorption in the higher layers of the ionosphere. During the eclipse, theD region absorption decreases in phase with the progress of the eclipse, but the variation of deviative absorption may differ in each observation. The deviative absorption is large when the equivalent frequency is close to the critical frequency of the layer reflecting the waves or of the layer just penetrated by the waves. The changes in the deviative absorption during an eclipse can be estimated on the basis of the variation of the critical frequencies of the ionospheric layers. The resultant changes in the total absorption during a solar eclipse may thus be estimated. The different types of field strength variation expected during an eclipse are given.The observations of the vertical incident absorption of radio waves and the field strength variations of obliquely incident continuous wave radio signals during the solar eclipse are described and the changes are explained on the basis of the above theory. 相似文献
17.
The longest total solar eclipse during the 21st century occurred in South and East Asia on July 22, 2009. Ionospheric response to this rare total solar eclipse which was observed right from the time of sunrise in the Indian zone, has been studied in terms of the total electron content (TEC) obtained from three global positioning system (GPS) receivers located at Udaipur, Hyderabad and Bengaluru, and electron density obtained using space based GPS-Radio Occultation technique. The study reveals significant reductions in the electron density and TEC that persisted up to 2 h past the last contact even during early morning eclipse. These observations imply that during the early morning eclipse, the production and loss of ionization dominate over the plasma transport processes. 相似文献
18.
日偏食对低纬地磁场的影响 总被引：1，自引：0，他引：1
１９９５年１０月２４日日偏食期间，我们在海南省琼中进行了地磁场总强度的观测和分析，同时运用该地磁台三分量磁照图，分析了地磁Ｄ场Ｄ、Ｈ、Ｚ三分量在日偏食期间的变化特征。结果表明：日偏食期间，磁偏角初亏后逐渐偏东，食甚后偏西；水平强度和总强度初亏后逐渐变小，食甚后上升；垂直强度初亏后逐渐变大，食甚后约１个小时变小。 相似文献
19.
L. F. Chernogor 《Geomagnetism and Aeronomy》2010,50(3):346-361
Quasi-periodic variations in the Doppler shift of the HF range frequency at a vertical path and critical frequency of the
F
2 layer caused by wave disturbances in the ionosphere on the day of the partial (the magnitude was about 0.42) solar eclipse
and on background days are analyzed. For the spectral analysis, the window Fourier transform, adaptive Fourier transform,
and wavelet analysis were jointly used. It is shown that on the day of the eclipse and the background day, spectral characteristics
of wave disturbances within the 150–200 km height range differed substantially. The changes in the spectral composition began
approximately 30–35 min after the solar eclipse beginning and lasted more than 1.5 h. 相似文献
20.
巴布亚新几内亚日全食的地磁场效应 总被引：1，自引：0，他引：1
为了研究1983年6月11日日全食的地磁场效应,我们在巴布亚新几内亚的莫尔兹比港（Port Moresby）进行了地磁观测。经过资料分析,在消除当天的正常日变化和干扰变化后,日食效应比较明显,水平强度减小（-3.6±1.2nT）,磁偏角偏东（0.6′±0.1′E）和垂直强度增加（5.0±1.1nT）。证实了日全食引起地磁场强度和方向的变化,与食分、食甚持续时间、太阳高度角（即日食发生的地方时）和季节有关。 相似文献