Showing papers on "Solar eclipse published in 1979"
TL;DR: In this paper, the use of measurements combined with detailed stratospheric modeling of time dependent events, to confirm chemical mechanisms and their laboratory rate constants, is examined, and proposed measurements of the time dependent behavior of NO and NO2 to be made by U2 aircraft at 20-km altitude are also discussed.
Abstract: The use of measurements combined with detailed stratospheric modeling of time dependent events, to confirm chemical mechanisms and their laboratory rate constants, is examined. Careful simultaneous solutions of these equations have shown a significant daytime variation of ozone down to altitudes of about 30 km that can affect the interpretation of spectral absorption type experiments. The calculated sunset variations of NO and HO show a log linear concentration decay for limited time periods that can be readily converted into atmospheric temperatures by using known reaction rates up to about 70-km altitude. Proposed measurements of the time dependent behavior of NO and NO2 to be made by U2 aircraft at 20-km altitude are also discussed.
65 citations
TL;DR: In this article, the surface layer turbulence follows a continuum of equilibrium states in response to stability changes brought about by the change in surface heat flux during a solar eclipse of 80% totality, and the response of the rms velocity fluctuation lags behind that of rms temperature fluctuation by about 20 min.
Abstract: Measurements of velocity and temperature fluctuations were made over a period including a solar eclipse of 80% totality to determine the _response of surface layer to the change in ground heat flux. The response of the rms velocity fluctuation lags behind that of the rms temperature fluctuation by about 20 min. Although the velocity spectrum exhibits a good inertial subrange for the whole period of observation, the inertial subrange in the temperature spectrum disappears shortly after the start of the eclipse. It is found that during the eclipse the surface layer turbulence approximately follows a continuum of equilibrium states in response to stability changes brought about by the change in surface heat flux.
52 citations
01 Jan 1979
TL;DR: The Times reported that the greatest possible interest had been aroused in scientific circles by the hope that rival theories of a fundamental physical problem would be put to the test, and there was a very large attendance of astronomers and physicists as mentioned in this paper.
Abstract: “REVOLUTION IN SCIENCE/NEW THEORY OF THE UNIVERSE/NEWTONIAN IDEAS OVERTHROWN.”1 These were headlines in the Times of London on Friday, Nov. 7, 1919. Here the Times reported the extraordinary joint meeting of the Royal Society of London and the Royal Astronomical Society on the afternoon of the previous day where results obtained from the total solar eclipse of the twenty-ninth of May, 1919, were announced. The principal aim of the British observations of this eclipse was to test rival laws concerning the path of light passing near the sun. The Times reported that “The greatest possible interest had been aroused in scientific circles by the hope that rival theories of a fundamental physical problem would be put to the test, and there was a very large attendance of astronomers and physicists.” According to the Times report, the Astronomer Royal, Frank Watson Dyson, “convinced the meeting that the results were definite and conclusive” and it was “generally accepted” that Einstein’s relativity theory of gravitation had been confirmed and the Newtonian theory had been overthrown.
21 citations
TL;DR: In this article, the results of accurate group height measurements of the ionosphere which were taken in the path of totality of a solar eclipse were presented, and a tentative model was proposed that explains these periods and the periods reported for the 1973 West African eclipse.
14 citations
TL;DR: In this article, a one-dimensional transport-kinetics model is used to examine the variations in stratospheric minor species concentrations expected to occur during an eclipse of the sun.
Abstract: A one-dimensional transport-kinetics model is used to examine the variations in stratospheric minor species concentrations expected to occur during an eclipse of the sun. The short chemical lifetime of some of the important stratospheric species suggest that significant variations in concentration of some species are expected. Species which show large diurnal behavior, such as NO and OH, should be expected to have especially noticeable changes during the eclipse. Such variations during an eclipse, if measured, could provide a validation for the short response time chemistry in several catalytic cycles currently used in models of stratospheric chemistry.
13 citations
TL;DR: In this article, the results available on ion composition and electron densities from the rocket measurements carried out during the total solar eclipse of November 12, 1966, at Cassino, Brazil, are subjected to a detailed numerical analysis using the presently known ion chemistry models for the D and E regions.
Abstract: Results available on ion composition and electron densities from the rocket measurements carried out during the total solar eclipse of November 12, 1966, at Cassino, Brazil, are subjected to a detailed numerical analysis using the presently known ion chemistry models for the D and E regions. Solutions of the continuity equations applicable to the individual ionic species are carried out under equilibrium conditions to determine the ion production rates that can best represent the rocket measurements of the ion composition and electron density carried out to represent the full sun conditions. The ion production rates so derived are then inserted in a set of time dependent solutions of the continuity equations to predict the ion density height distribution during the eclipse corresponding to the available rocket measurements. A comparison between the calculated results and the observations during the totality is then made to determine the residual ion production rates in the lower ionosphere, from which the part that cannot be accounted for by solar radiation is attributed to the precipitation of high-energy particles in the South Atlantic geomagnetic anomaly. The results are discussed in the light of the previous estimates of the ion production rates based on the nighttime occurrence of blanketing type Es in the anomaly region.
10 citations
Journal Article•
9 citations
5 citations
TL;DR: In this paper, the ion chemistry of the lower ionosphere was used to deduce the height distribution of nitric oxide concentration in the region from 80 to 110 km, compared with other available experimental determinations of the NO height distributions using rocket borne radiometric measurement of NO gamma band emissions in the day glow.
Abstract: Ion composition results obtained by Narcisi et al. from rocket observations carried out during the November 1966 solar eclipse campaign at Cassino, south Brazil, are analysed on the basis of the presently known detailed ion chemistry of the lower ionosphere, to deduce the height distribution of nitric oxide concentration in the region from 80 to 110 km. The results are compared with other available experimental determinations of the NO height distributions using rocket borne radiometric measurement of NO gamma band emissions in the day glow.
3 citations
TL;DR: In this article, it was shown that internal gravity waves generated by the 23 October 1976 total solar eclipse would have come to a focus in a region well north of Australia, and also in Antarctica.
Abstract: Calculations are presented which suggest that internal gravity waves generated by the 23 October 1976 total solar eclipse would have come to a focus in a region well north of Australia, and also in Antarctica. No evidence is found for a focus in Western Australia, as suggested by Beer et al. (1976).
TL;DR: In this paper, measurements of the direct solar radiation during the annular solar eclipse of April 29, 1976 are given in three wavelength bands (centered on 800, 680, and 450 nm).
Abstract: Measurements of the direct solar radiation during the annular solar eclipse of April 29, 1976 are given in three wavelength bands (centered on 800, 680, and 450 nm). A decrease of the solar radiation after the last contact was observed, especially in the red and infrared. This is considered in connection with the results of other direct light and zenith light measurements.
TL;DR: In this article, a survey of the geomagnetic Ci index for the years 1906-1976 (164 eclipses) was performed by using a modified version of the well-known t test for the difference of two means to define eclipse departure probability (Pd).
Abstract: Solar eclipses occur with periodicities of 29.53 days, 6 months, 8.85 years, and 18.6 years. Since these are nearly commensurate with known solar-terrestrial event repetition cycles (27.3 days, semiannual, and 11 years), searches for possible solar eclipse effects in daily geophysical data using standard autocorrelation techniques are likely to have serious side-band interference problems. Therefore a survey of the geomagnetic Ci index for the years 1906–1976 (164 eclipses) was performed by using a modified version of the well-known t test for the difference of two means to define eclipse departure probability (Pd). Eclipse epoch Ci changes are shown to satisfy a simple probabilistic model composed of two events—one due to the eclipse E and another due to a ‘background’ of zero ecliptic latitude Ci fluctuations ZL such that the mean values of the departure probabilities are 〈Pd(E|ZL)〉 = 0.5±0.1, 〈Pd(E)〉 = 0.3 ± 0.1, and 〈Pd(ZL|E)〉 = (1.8±0.2)〈Pd(ZL)〉. It is also shown that the derived 〈Pd(E)〉 value is consistent with a simple statistical occulation model and the Pd derived from geomagnetic effects observed during one total solar eclipse. The large and persistent conditional probabilities, however, appear to require some sort of geomagnetic reverberation effect between the earth and moon.