A theory of radiative transfer has been developed which describes quantitatively the radiative features of resonant atomic and molecular emissions in the upper stratosphere, mesosphere and the thermosphere. Three typical cases have been studied: (1) the transfer of a single emission line (single ground state and single excited state), (2) the transfer of an optically coupled multiplet (multiple ground states and single excited state), (3) the transfer of thermally coupled multiple emission lines (multiple-stated ground and excited levels, whose internal states are in thermodynamical equilibrium by particle collisions). Mathematical formalisms are established for the transfer processes in a plane-parallel, horizontally homogeneous, Doppler-broadening atmosphere having external and internal primary sources of excitation. The primary sources contain (1) the resonance fluorescence of solar radiation, (2) the resonance fluorescence of the earth-shine, (3) the excitations due to thermal collisions of particles, (4) the excitations due to chemical reactions of atmospheric particles. Attempt has been made to formulate explicitly these excitation sources.

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The paper discusses the daily variation of the geomagnetic H-field averaged over the Five International Quiet days, Sq(H), at low latitude stations. The Sq(H) at a station near the dip equator during a low sunspot year represents an increase from about 0600 LT to 1600 LT and an almost constant value from 1600 LT throughout the night time. During a high sunspot year the H-field continues to decrease from noon to evening and through the night time up to sunrise, there being no period in the night when the field remains constant.
The harmonic analysis of Sq(H) curves shows that the local time of maximum of the diurnal as well as the semidiurnal wave advances towards local noon with the increase of the average sunspot number. During minimum sunspot years the daily maximum in H occurs almost at 1100 LT while during maximum sunspot years the maximum occurs at about 1200 LT.
The amplitudes (C₁) of the diurnal and (C₂) of the semidiurnal waves are shown to increase linearly with sunspot number. For any of the stations, the rate of increase of the diurnal component with sunspot number is about 2.5 times which is remarkably larger than the corresponding rate of about 1.8 times for the semidiurnal component, such that the ratio C₁/C₂ at the low latitude stations is about 1.7 in 1964 and about 2.0 in 1959.
The monthly mean daily range, rSq(H), shows a predominant semiannual variation with equinoxial peaks at the equatorial stations and a predominant annual variation with summer maximum at the non-equatorial station Alibag. A linear increase of the annual mean daily range with Zurich mean sunspot number Rz is established, the rate of increase being larger towards the equator.
The dependence of the diurnal range on the sunspot number is due to enhanced E-region ionization with increasing sunspot number. The delay in the time of diurnal maximum with increasing Rz, the semiannual variation of rSq(H) at equatorial stations and the annual variation of rSq(H) at nonequatorial stations are suggested to be due to the effects of E-region electric fields.

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Seven geomagnetically disturbed days were studied at a number of stations in the American Hemisphere for the purpose of determining the systematic spectral composition changes with activity level, Ap, and geomagnetic latitude. The spectral amplitudes, A, at 5, 10, 30, 60, and 120-min period, T, from a Fourier analysis of magnetograms showed a linear relationship with Ap that varied with T. There was an auroral latitude maximum of activity at all periods (which shifted poleward for lower Ap), a low latitude minimum, and a daytime equatorial enhancement of the spectra. Calling m the spectral slope from A=kT^m, where k is a constant, the slopes were determined for the period ranges of 5 to 10, 10 to 60, and 60 to 240min. Average slope values in these ranges were about 2.4, 1.0, and 0.8 respectively. The 10 to 60-min slope values increased linearly with increasing Ap and decreased at auroral latitudes.

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Twenty-one resistivity changes as precursors of an earthquake as observed by means of a Yamazaki resistivity variometer are analyzed. On the basis of a Weibull distribution analysis applied to the observed data, it is made clear that a characteristic parameter of the distribution of precursor time takes on an almost the same value as that for a group of short-term precursors, such as land deformation, tilt and strain, and underground water. No correlation between earthquake magnitude and precursor time is alsofound for both the groups. It is surmised that the resistivity precursors, as well as the others cited in the above, may be caused by preliminary failure immediately prior to the main rupture in the earth's crust.

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The third Japanese scientific satellite “TAIYO”: has accomplished the first ten month mission during a period of minimum activity of the sun. The onboard electron temperature probe worked perfectly during this mission, obtaining the distribution of electron temperature in the height region from 250km to 3, 000km in the low latitude of ±31 degrees. The solar radio flux as well as the sunspot number was almost constant and low except for some enhancement especially in August 1975. Therefore, the electron temperature was also quite stable and showed regular characteristics in time and space without being disturbed by the geophysical disturbance. In the present paper, the orbital variation of electron temperature is carefully examined. Also, the mean electron temperature profiles in the nighttime at some particular localities are discussed. Among them, the profiles obtained in the geomagnetic South Atlantic anomaly region show a remarkable temperature gradient in both the ionosphere and protonosphere. These anomalous distributions of electron temperature suggest close coupling of the protonosphere and the ionosphere in this anomaly region.

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