摘要:

A chemical method for the automatic and quantitative recording of atmospheric ozone near the ground, from aircraft, or by means of sounding balloons, is described. A network of surface ozone recording stations is now being established in New Mexico and one airborne unit has been flown in an airplane. Preliminary recordings are communicated.

ISSN:0148-0227    

DOI:10.1029/JZ056i003p00307

年代:1951

数据来源: WILEY

摘要:

Observations in the Mojave Desert of the diurnal variations of the zenith intensity of the forbidden oxygen line at 5577 Å for ten nights over a two‐year interval are recorded. In general, a maximum of intensity occurs at local midnight, ±2.5 hours. A detailed study of one night is reported wherein the diurnal variation of regions of the sky other than the zenith are shown to follow time patterns similar in general but with significant variations in detail. The intensity changes of various parts of the sky are interpreted as geographical variations of local zenith intensity. Isophotal plots of these geographical variations throughout the night indicate the presence of definite patterns in the upper atmosphere. During the post‐twilight period, an enhancement of intensity is observed in the western sky. In the predawn observations, no enhancement is noted in the eastern sky. Between the post‐twilight and predawn, the intensity goes through a maximum which is partially localized to the north of our station. Evidence is presented which indicates that the over‐all intensity change can be described as a fixed excitation pattern on the dark side of the earth through which a given observer seems to move with the rotation of the earth. The character of the pattern seems to change with the season. The variation of intensity with zenith distance for the whole night indicates an effective height of emission

ISSN:0148-0227    

DOI:10.1029/JZ056i003p00325

年代:1951

数据来源: WILEY

摘要:

A method is presented for obtaining solutions to the one‐dimensional wave equationwhich arises in the course of the application of the wave theory to the study of the ionosphere. The π's represent characteristic wave functions of the ionosphere,K0the propagation constant of free space, ∈(x) the complex index of refraction of the ionosphere, and the primes denote differentiations with respect to the space coordinatex. The method has been applied to the following “E‐layer” problem with good results.Operating frequency —150 kc/sec Angle of incidence —NormalN(electron density) —Chapman spatial distribution with various values of maximum electron density ν (collisional frequency) —Exponentially decreasing with heightH(scale height) —10 km (constant) Earth's magnetic field —Evaluated at 100 km over State College, Pennsylvania Dispersion theory —Appleton‐Hartree (Sellmeyer)An example of the method for obtaining the wave functions and reflection coefficients is carried out in detail, and reflection coefficients are presented for five different values of maximum electron density. This method is compared with the ray optics and the W.K.B. method. The results are compared v

ISSN:0148-0227    

DOI:10.1029/JZ056i003p00355

年代:1951

数据来源: WILEY

摘要:

This paper discusses in two parts the lowermost region of the ionosphere, namely, theD‐layer. In Part I, a résumé of the present state of our knowledge is given. In Part II, new theoretical studies are made on the formation and structure of the layer, based on contemporary knowledge. It is assumed that theD‐layer is produced by ionization of O2at the first ionization potential, as first suggested by S. K. Mitra,et al. The number densities of electrons and ions are calculated for various heights, taking due account of the variations of atmospheric temperature and effective recombination coefficient with height. The number density distribution of electrons does not show any maximum; that of ions, however, gives a maximum at nearly the same height as that of the rate of ion production. The distributions obtained have been used to give (i) the variation of reflection height with solar zenith angle (for long and very long waves), and (ii) values of the coefficient of reflection for various frequencies at the low frequency

ISSN:0148-0227    

DOI:10.1029/JZ056i003p00373

年代:1951

数据来源: WILEY

摘要:

Results of vertical‐incidence pulse observations at the Central Radio Propagation Laboratory, National Bureau of Standards, show that ionospheric storms have appreciable effects on the reflective properties of theE‐region at night. Daytime effects of storms are limited primarily to periods of high absorption, coinciding with similar effects at higher frequencies. Data obtained at 160 kc indicate that the character of low frequency reflections at night may be a sensitive indication of storminess. Correlation is shown between magneticK‐indices and low frequency data. During storms, effects have been of such magnitude that they cannot be ignored in design of low‐frequency navigational or high‐speed communication

ISSN:0148-0227    

DOI:10.1029/JZ056i003p00403

年代:1951

数据来源: WILEY

摘要:

Ionospheric measurements made during eclipses are analyzed and, together with recently acquired solar data, are used in a reexamination of the theories of the ionosphere. It is shown that:(i) The rates of disappearance of electrons in all the principal layers may be much higher than hitherto believed. If so, then the number of ionizing quanta needed is also greatly increased.(ii) There is probably a non‐solar source of electron production in regionE(and perhaps regionD). It may be the electric currents flowing in the upper atmosphere which are also manifested by fluctuations in the earth's magnetic field.(iii) Solar ionizing radiation does not appear to originate (principally) either throughout the corona or near the photosphere, but in regions of rapid temperature transition in the chromosphere and lower corona. Excess emission occurs, as has been shown previously, from regions of disturbance, often near sunspots.(iv) The emission spectrum of these regions may be strong in the quasi‐Lyman spectrum of HeII and in X‐rays of wave‐length ranging down to about 3 Å. During flares, X‐rays of wave‐length less than 1 Å may be emitted.(v) TheF1 andF2 ionospheric layers may be accounted for if minor modifications of existing theories are made. TheEandDlayers may be formed by quanta of a few hundred and a few thousand electron volts, respectively, originating in the chromospheric tran

ISSN:0148-0227    

DOI:10.1029/JZ056i003p00409

年代:1951

数据来源: WILEY

摘要:

The list of magnetic observatories gives for the 72 stations in operation the geographic position and the abbreviation for each one. Among the newer observatories, either in operation or under construction, are Nurmijärvi in Finland, Průhonice in Czechoslovakia, Memanbetsu in Japan, El Abiod, Beni‐Abbès and M'Bour in French Colonial Africa, and Muntinlupa in the Philippine Islands. Speaking in general terms, the annual values are for recent years and follow after those published in the September 1948 issue of the Journal of Terrestrial Magnetism and Atmospheric Electricity. Values for the year 1950 have been supplied by several observatories; in fact, many more than expected, a pleasant augury of recrudescent interest in geomagnetism. Values over comparatively extended periods are tabulated for La Quiaca, Pilar, and Laurie Island (Orcadas), all in Argen

ISSN:0148-0227    

DOI:10.1029/JZ056i003p00431

年代:1951

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JZ056i003p00439

年代:1951

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JZ056i003p00442

年代:1951

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JZ056i003p00445-01

年代:1951

数据来源: WILEY