摘要:

Effective with this issue,Radio Sciencewill be published under the sole editorial control of the U. S. National Committee of the International Union of Radio Science (URSI). As most of you know, it has been published since 1964 by the Department of Commerce with the cosponsorship of USNC/URSI. The new publisher is the American Geophysical Union (AGU), which currently publishes several leading journals in the geophysical sciences. The interests of AGU and USNC/URSI are complementary; because the Council of the AGU serves as the U. S. National Committee of the International Union of Geodesy and Geophysics (IUGG), an international complementarity of interests also exists.

ISSN:0048-6604    

DOI:10.1029/RS004i001p00001

年代:1969

数据来源: WILEY

摘要:

The International Scientific Radio Union,1better known as URSI (an abbreviation derived from the French name, Union Radio Scientifique Internationale), is one of the oldest of the family of scientific unions comprising the International Council of Scientific Unions (ICSU). The Union was founded in 1913 under the title ‘International Commission of Scientific Wireless Telegraphy,’ and it celebrated its golden jubilee in 1963 in conjunction with a general assembly held in Tokyo. The history of the Union, and the development of its commissions, and programs, and worldwide services, was recorded in the URSI Golden Jubilee Memorial volume published by the URSI Secretariat in 1963. The aims of the Union as stated by the late J. H. Dellinger in his history of the URSI in the Jubilee Memorial are2:1. To promote international cooperation in the scientific study of radio.2. To encourage and aid in the organization of radio research requiring cooperation on a large scale.3. To promote the establishment and use of common methods and standards of measurement.4. To encourage and aid the discussion and dissemination of the results of these activit

ISSN:0048-6604    

DOI:10.1029/RS004i001p00003

年代:1969

数据来源: WILEY

摘要:

The community of radio scientists in the United States participates in URSI through a committee of the Division of Physical Sciences of the National Research Council. The Research Council was organized in 1916 by the National Academy of Sciences at the request of President Wilson to enable the broad community of scientists and engineers in the country to associate its efforts with those of the more limited membership of the Academy in service to science and the nation. Members of the Research Council and its committees, boards, and panels are drawn from governmental, academic, industrial, and other institutions and organizations throughout the country. The Research Council is supported by private and public contributions, grants, and contracts, and by voluntary contributions of time and effort by several thousand of the nation's leading scientists and engineers.

ISSN:0048-6604    

DOI:10.1029/RS004i001p00007

年代:1969

数据来源: WILEY

摘要:

This paper describes an experimental investigation of the 1.63‐mm H2O absorption line for nitrogen‐water‐vapor mixtures and for oxygen‐water‐vapor mixtures. Frequency sweep measurements were made at pressures between 1 and 5 mm of mercury and measurements at discrete frequencies were made for pressures between 200 and 760 mm of mercury. These measurements were made over a range of temperatures from 242° to 325°K. Data for the attenuation and line breadth constant as a function of temperature ar

ISSN:0048-6604    

DOI:10.1029/RS004i001p00009

年代:1969

数据来源: WILEY

摘要:

The observed diurnal phase changes of VLF radio waves show large deviations from the theoretical first‐mode phase change. The main features of the deviations are explained by the presence of a second mode that is larger than the first mode at night but that is small during transitions and during daytime. The data indicate that for frequencies above 16 kHz, nighttime second‐mode dominance extends out to several megameters from the transmitter, in agreement with theoretical predicti

ISSN:0048-6604    

DOI:10.1029/RS004i001p00017

年代:1969

数据来源: WILEY

摘要:

Analytical formulas including those for group and phase paths for radio rays in quasiparabolic (ionospheric) layers with spherical symmetry are presented in a convenient table. Their most important singularities are summarized in another table. By means of these formulas a transmission‐slider technique is presented for the determination of the shapes of oblique ionograms. The phenomenon of low‐angle cutoff is explained as well as the phenomenon of the trapping of waves. For a trapped wave it is shown that the group path between successive reflections is independent of the direction of the ray. The properties of rays in spherical layers are summarized, and some simple cases with nonspherical layers are discussed. In particular, a method is given for ray tracing in a we

ISSN:0048-6604    

DOI:10.1029/RS004i001p00023

年代:1969

数据来源: WILEY

摘要:

The irregularities that produce the partial reflection of radio waves (1.5–6.0 MHz) from the D region are investigated. Experimental evidence indicates that reflection usually occurs from localized irregularities rather than from a region of smaller scale turbulenc

ISSN:0048-6604    

DOI:10.1029/RS004i001p00035

年代:1969

数据来源: WILEY

摘要:

A new formulation of the single‐polynomial analysis is presented, in which the electron density profile is assumed to begin with a flat base at a height equal to the lowest measured virtual height. This formulation gives a more accurately defined profile with only a small number of points and agrees with the assumptions normally made. Near the critical frequency he electron density profile is required to approach a parabolic distribution. Coefficients are given for the rapid analysis of ionograms taken anywhere in the world. The height of the peak, the scale height at the peak, and the subpeak electron content, along with five or six points on the electron density profile, are obtained directly from a small number of measured virtual height

ISSN:0048-6604    

DOI:10.1029/RS004i001p00041

年代:1969

数据来源: WILEY

摘要:

Sweep‐frequency CW radio signals transmitted over 1300‐km north‐south and 1900‐km east‐west temperate‐zone paths were received 24 hours per day for 21½ ‐day periods. Measurements of the incoming one‐hop F‐layer polarization, as a function of time‐of‐day and radio frequency, indicate that daytime rates of change of polarization rotation with frequency (at an instant of time) average 1 turn/MHz over the north‐south path and 0.25 turn/MHz over the east‐west path. These values are in good agreement with computer raytracing predictions of the rates of change of polarization rotation with frequency over similarly disposed paths. It was observed that nighttime polarization rotation rates are about 1 to 4 times as high as those measured during the day. It was also experimentally found that the rate of change of the incoming polarization with frequency first decreased and then increased with incoming radio frequency, the minimum rate occurring near 0.8 MOF0. Daytime rates of polarization rotation with time (at a given frequency) average 0.25 turn/min. The polarization rotation rates with time do not appear to vary either with path azimuth or transmitted radio frequency. Near‐zero rates of polarization rotation with time occur for much of the nighttime period. Large fluctuations in the polarization variations occur with both time and frequency throughout the day.Polarization measurements made with signals that were reflected from a nonblanketing, nighttime sporadic E layer of about two hours duration indicate that, for this layer, circumstances other than polarization effects, probably multipath, determine much of the observed signal strength variations with frequency and time.The results suggest that for round‐the‐clock temperate zone propagation, when linearly polarized antennas are employed, a qualitative threshold for envelope distortion of broadband signals (due to variation in the incoming polarization with frequency) occurs when signal bandwidths exceed approximately 100 kHz for north‐south paths and 400 kHz for east‐west paths. The effects of such distortion may be reduced either by operating near 0.8 MOF0or by the

ISSN:0048-6604    

DOI:10.1029/RS004i001p00053

年代:1969

数据来源: WILEY

摘要:

It is shown that an exact equivalence exists between a monochromatic correlator interferometer using directional antennas and a wideband correlator interferometer using isotropic antennas. The necessary relationship between the frequency response function of the receiving system and the aperture illumination of the antennas to achieve the equivalence is derived.

ISSN:0048-6604    

DOI:10.1029/RS004i001p00069

年代:1969

数据来源: WILEY