摘要:

Data over the ascending and descending parts of the recent sunspot‐cycle from widely distributed ionosphere stations have been utilized to trace the geographic features and nature of the spread‐Fequator in low latitudes. Indications are that the spread‐Fequator is nearly a great circle, approximately parallel to the geomagnetic equator, but swinging, during an 11‐year period, through an angle of plus and minus 25° of latitude, about an axis through Japan and Argentina. The two fundamental types of spreadF(polar and equatorial) and forkedFare d

ISSN:0148-0227    

DOI:10.1029/JZ061i002p00157

年代:1956

数据来源: WILEY

摘要:

Indirect measurements of the heights at which ionospheric scattering of VHF waves occurs, using the technique of measureing the differences in the times of arrival of tropospheric and ionospheric pulses received over an 810‐km oblique‐incidence path, were made by the National Bureau of Standards in November 1952 and in January 1953. These measurements show approximate heights of 86 km and 70 km, respectively, for the night‐time hours and the midday hours. The accuracy of the heights obtained in this way are subject to uncertainties about the actual tropospheric d

ISSN:0148-0227    

DOI:10.1029/JZ061i002p00165

年代:1956

数据来源: WILEY

摘要:

The aerodynamic basis of using Pitot‐tube pressure at supersonic speeds as an indirect measurement of the upper atmospheric density, pressure, and temperature, up to 80 km, is discussed. A special means of deduction of these ambient variables from corresponding Pitot‐tube pressure and other relevant parameters is presented. A unique feature of the method is that it needs only the Pitot‐tube pressure and the corresponding forward velocity of the Pitot tube (assuming negligible atmospheric wind‐velocity) to determine the ambient variables. This simplification is made possible by invoking laws which describe the characteristic properties of the atmosphere. This simplification, in the physical sense, results in an integral equation for the ambient density. A special and effective method is developed for the solution of this e

ISSN:0148-0227    

DOI:10.1029/JZ061i002p00171

年代:1956

数据来源: WILEY

摘要:

This paper summarizes the results of an extensive investigation of the relation betweenKpand the intensity of the emission‐line corona. We consider the coronal intensity in the northern and the southern solar hemispheres separately, and find that the intensity in the hemisphere on the same side of the solar equator as the earth shows the closer relation toKp. We discuss the identification ofM‐regions with areas of unusually weak 5303 cor

ISSN:0148-0227    

DOI:10.1029/JZ061i002p00179

年代:1956

数据来源: WILEY

摘要:

An integral relation is derived between the electron density distribution of a multilayer and the frequency dependence of the time in which a radio pulse traverses the layer. This integral equation is then solved for the electron distribution by means of the Mellin transform, given the transit time function. The lack of uniqueness of this solution is discussed. Certain characteristics of the multilayer, for example, the minimum electron density, are given in terms of the Mellin transform of the transit time.

ISSN:0148-0227    

DOI:10.1029/JZ061i002p00183

年代:1956

数据来源: WILEY

摘要:

In this paper, charge transfer reactions which remove the identity of ions are discussed in detail in terms of their value to upper atmospheric research. For reactions involving Ca+ions, it is found that the energy defects are large, but for H+the defects are generally small, so that when these latter ions have practically lost all their energy the reactions are most probable to occur. As in the case of protons, Ca+ions, in collision with atmospheric gases, are expected to excite certain Ca lines and also certain lines and bands of atmospheric gases.It is shown that by means of the charge transfer reactions it is possible to derive both the ratio of the density of O+to the O+2ions and the effective recombination coefficient for theFlayer. However, for nearly all other reactions, it is found that the low energy ions present in the ionized layers of the atmosphere have low cross‐section

ISSN:0148-0227    

DOI:10.1029/JZ061i002p00193

年代:1956

数据来源: WILEY

摘要:

Impure magnetites, containing an appropriate amount of aluminum or other elements with an average charge of about 3 (for example, titanium + magnesium, titanium + vacancies, etc.), may undergo a reversal in their direction of magnetization as a result of an ionic ordering process during and after cooling. Gorter has shown that this phenomenon occurs in the compound NiFeAlO4. Some natural magnetites have compositions which suggest that they would be self‐reversin

ISSN:0148-0227    

DOI:10.1029/JZ061i002p00201

年代:1956

数据来源: WILEY

摘要:

Results of an investigation are given associating recurrent 27‐day geomagnetic activity withM‐regions of the sun, around years of sunspot minima. The association ofM‐sequences with various solar features of the disk and corona is also indi

ISSN:0148-0227    

DOI:10.1029/JZ061i002p00211

年代:1956

数据来源: WILEY

摘要:

Radioactive age determinations have been made on 16 minerals from the Brown Derby pegmatite and the Quartz Creek granite. A high degree of consistency has been found among the Rb‐Sr ages measured on micas and feldspars. A similar degree of consistency exists in the K‐A ages of micas. These consistencies are indicative of the usefulness of measurements of the decay of K40and Rb87in determining relative ages of igneous rocks. U‐Pb and Th‐Pb ages determined from minerals obtained from the pegmatite and granite were not concordant. Different minerals showed different types of partial separation of parent and daughter elements. Comparisons of Rb‐Sr and K‐A ages with concordant U‐Pb ages have been made on other pegmatites. The measurements are most consistent with an age of 1350±100 m.y. for the pegmatite a

ISSN:0148-0227    

DOI:10.1029/JZ061i002p00215

年代:1956

数据来源: WILEY

摘要:

Certain characteristics of radio signals, propagated by reflection from meteor ionization trails from a low‐power continuous‐wave transmitter 960 km distant, were studied at radio frequencies of 23.2, 46.4, and 92.8 Mc. In particular, the percent of the total time that meteor reflections were detectable at each frequency is presented, and shown to be in qualitative agreement with theoretical expectations. Simultaneous recordings were also made of signals from a second remote transmitter operated at 23.1, 46.2, and 92.4 Mc, and located at various distances along, and at right‐angles to, the propagation path. From the percent time that signals received from the second transmitter were coincident with those from the first, it is concluded that reradiation from the numerous, low‐density trails is highly directional, and that the fading, long‐enduring echoes from the relatively‐infrequent, high‐density trails are considerably less directional. When the transmitters were spaced in a direction perpendicular to the propagation path, the signal coincidence decreased much more rapidly with transmitter spacing than when the transmitters were spaced along the pro

ISSN:0148-0227    

DOI:10.1029/JZ061i002p00233

年代:1956

数据来源: WILEY