摘要:

A method is described by which routine (h′ ‐f) records can be analysed quickly to give information about the vertical distribution of electron density in the ionosphere. The method is approximate but is simple and quick to use, and is therefore convenient for making analyses of the type required for testing theories of the ionosphere. It consists in assuming, after Appleton, that the electron distribution is parabolic and then in constructing a series of curves, similar to those of Booker and Seaton, on a transparent scale, in such a way that they can be matched directly to the photographic records. The important parameters can then be read directly from the scale. Retardation in theF1 layer can be allowed for when theF2 layer is being analysed. Scales based on other electron distributions are also described and are useful in the analysis of unusual records of the type sometimes encountered at Huancayo. An account is given of the calculation of the total number of electrons in a unit column of theF2 layer below the level of the maximum. The calculations are made on the assumption that the earth's magnetic field is zero, and the effect of removing this limitation is discus

ISSN:0148-0227    

DOI:10.1029/JZ056i004p00463

年代:1951

数据来源: WILEY

摘要:

A quick and approximate method was used to analyse (h′ ‐f) records of radio waves reflected from the ionosphere so as to give the total number (n) of electrons below the level of maximum electron density in a column of unit cross‐section in theF2 region. The, analysis was carried out on records obtained at Watheroo (Australia), Huancayo (Peru), and College (Alaska) for two magnetically quiet days per month in a year of sunspot maximum and a year of sunspot minimum. It was found that the quantitynwas closely related to the zenith angle (χ) of the sun's rays, whereas it is well known that the maximum electron densityNmin theF2 layer is not simply related to this angle. The well‐known anomalies which are apparent whenNmis studied as a function of time of day, time of the year, and geographical position, all seemed to disappear when the quantitynwas studied instead. A new kind of anomaly which was observed at Huancayo in years of sunspot minimum is described and discussed. A relation between the thickness and the height of theF2 layer is established and the possibility of using it in ionospheric forecasting and theory is discussed. Since the deductions of this paper are made on data from only three stations, it is suggested that a similar analysis should be made for other stations. This is all the more necessary because two other sets of workers have reported results in disagreement with those obtained in th

ISSN:0148-0227    

DOI:10.1029/JZ056i004p00487

年代:1951

数据来源: WILEY

摘要:

An investigation of light scattering from a beam projected into the atmosphere over New Mexico has been made by means of the searchlight technique. The beam intensity is modulated by a shutter mechanism fronting the searchlight in order to differentiate the scattered light from the light of the night sky. A 60‐inch parabolic mirror and photo‐multiplier tube mounted at its focus comprise the sensing device. A narrow‐band tunable amplifier then selects the desired signal component from the photo‐multiplier output. Absolute values of atmospheric densities were obtained by assuming Rayleigh scattering and matching the measured response at 15 km with the densities obtained from radiosonde measurements at that height. Eight vertical density‐distributions to 61.8 km were so determined. They are in good agreement with the Rand distribution for a model atmosphere. A seasonal trend for densities at high altitudes i

ISSN:0148-0227    

DOI:10.1029/JZ056i004p00509

年代:1951

数据来源: WILEY

摘要:

A study of fading patterns of pulsed radio waves reflected by the ionosphere has led to the determination of horizontal drifts in the ionosphere. Equipment has been operated at 2.3 Mc at the National Bureau of Standards since March 1949. The wind may blow from any direction over a period of time. It exhibits diurnal characteristics which change with the seasons. Apparent wind speeds may range up to 300 m/sec, but are predominantly in the range from 50 to 100 m/sec. Marked changes in the character of the winds are associated with the transition fromE‐ toF‐region reflections. Good agreement is found between wind directions and speeds observed at Washington, D.C., and those observed at Cambridge, Engl

ISSN:0148-0227    

DOI:10.1029/JZ056i004p00521

年代:1951

数据来源: WILEY

摘要:

This paper is the last in a series designed to determine the path of electromagnetic energy flow in media of complex natures. In it, the common method of using the Poynting vector is extended to dissipative media. It is found preferable to replace Pointing's vector by Macdonald's to obtain physically suitable results, but even then the direction obtained for the energy flow shows a discrepancy with that found by packet methods. No conclusive decision can be reached, but argument appears to favour the packet as giving the observable energy flow.

ISSN:0148-0227    

DOI:10.1029/JZ056i004p00535

年代:1951

数据来源: WILEY

摘要:

Extensive aircraft measurements of the electrical conductivity of the atmosphere in fair weather were carried out over widely separated areas in the United States between February and November, 1950. Instrumentation of the plane is briefly discussed. The positive and negative conductivities were found to be equal throughout the altitude range of 35,000 feet investigated. The results are compared with those obtained earlier by other investigators. An expression for the electrical conductivity is derived on the basis of Thomson's theory of volume recombination of oppositely charged small‐ions, making use of Sayers' experimental results for air. This expression, taking into consideration the dependence of ionic mobility on temperature and pressure, together with the assumption that the smallion production above the first few kilometers is due entirely to cosmic rays, gives values in excellent agreement with those observed on the B‐17 and the B‐29 air

ISSN:0148-0227    

DOI:10.1029/JZ056i004p00545

年代:1951

数据来源: WILEY

摘要:

On account of the relative scarcity of data on nuclei over the oceans, the author repeated his earlier observations (1948) in July and August 1951 on the S.S.Americafrom New York to Le Havre and back.The average number of nuclei found per cubic centimeter for the western half of the Atlantic was 1,512 on the eastward trip and 1,229 on the westbound trip. On the eastern half of the Atlantic, the respective figures were 462 and 887. The mean (total) was 956 in July and 1,019 in August. Both figures are somewhat higher than in 1948.

ISSN:0148-0227    

DOI:10.1029/JZ056i004p00553

年代:1951

数据来源: WILEY

摘要:

Two identical flat ionization chambers were used to find the rate of ion formation (q) by beta, gamma, and cosmic rays at ground level and at one meter above ground. From the rate of ion formation, at one meter, due to alpha particles determined previously, the rate at the ground was calculated. The total ionizations at the ground and meter levels were found to be 11.48Iand 7.40I, respectively. Observations were made on the lawn of the garden of the Fordham University Seismic Station.

ISSN:0148-0227    

DOI:10.1029/JZ056i004p00557

年代:1951

数据来源: WILEY

摘要:

A graph is given that will aid in the rapid calculation of the density distribution of the upper atmosphere when the scale height and the scale height change with altitude are given.

ISSN:0148-0227    

DOI:10.1029/JZ056i004p00563

年代:1951

数据来源: WILEY

摘要:

Photoelectric observations of the nightglow on 5/6 January 1951 are analyzed and compared with similar observations made on the following night. The height of the oxygen layer, as deduced from the variation ofIz/Iowith zenith distance, is 200±25 km. Comparison of observations in the east and west with an isophote map based on the remainder of the sky provides semi‐quantitative support for the Roach‐Pettit hypothesis that there is an apparent westward diurnal motion of a stable excitation pattern. A height of 300 km is indicated by the time required for a given emission area to progress from east to

ISSN:0148-0227    

DOI:10.1029/JZ056i004p00567

年代:1951

数据来源: WILEY