Global Morphology of Ionospheric Scintillations II
Global Morphology of Ionospheric Scintillations II

Author: Jules Aarons

Publisher:

Published: 1975

Total Pages: 30

ISBN-13:

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Updating a review of the global morphology of ionospheric scintillations published in 1971, this study adds additional experimental studies on familiar topics to newer types of measurements of ionospheric irregularities, including in situ experiments and artificial heating of the F-layer.

Space Physics and Aeronomy, Ionosphere Dynamics and Applications
Space Physics and Aeronomy, Ionosphere Dynamics and Applications

Author: Chao Huang

Publisher: John Wiley & Sons

Published: 2021-05-11

Total Pages: 47

ISBN-13: 1119507553

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A comprehensive review of global ionospheric research from the polar caps to equatorial regions It's more than a century since scientists first identified the ionosphere, the layer of the Earth’s upper atmosphere that is ionized by solar and cosmic radiation. Our understanding of this dynamic part of the near-Earth space environment has greatly advanced in recent years thanks to new observational technologies, improved numerical models, and powerful computing capabilities. Ionosphere Dynamics and Applications provides a comprehensive overview of historic developments, recent advances, and future directions in ionospheric research. Volume highlights include: Behavior of the ionosphere in different regions from the poles to the equator Distinct characteristics of the high-, mid-, and low-latitude ionosphere Observational results from ground- and space-based instruments Ionospheric impacts on radio signals and satellite operations How earthquakes and tsunamis on Earth cause disturbances in the ionosphere The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals. Find out more about the Space Physics and Aeronomy collection in this Q&A with the Editors in Chief

Equatorial Scintillations
Equatorial Scintillations

Author: Jules Aarons

Publisher:

Published: 1976

Total Pages: 40

ISBN-13:

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With the advent of satellite communications systems at frequencies varying from approx. 140 to 1600 MHz, as well as navigation and ranging systems in the 1200 to 1600-MHz portions of the spectrum, the effect of equatorial irregularities on fading signals has become of importance. Recent observations of the signal statistics of scintillations at frequencies ranging from 136 MHz to 6 GHz reveal a power-law falloff of irregularity sizes. Power spectra are now available for a variety of conditions and for frequencies from vhf to microwaves. during periods of intense equatorial activity at frequencies to 360 MHz, Rayleigh scattering is frequently experienced.

Model of Equatorial Scintillations from in Situ Measurements
Model of Equatorial Scintillations from in Situ Measurements

Author: Sunanda Basu

Publisher:

Published: 1976

Total Pages: 32

ISBN-13:

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In situ measurements of F-region irregularity amplitude and ambient electron density made by the retarding potential analyzer (RPA) on OGO-6 near perigee altitude of 400 km have been utilized to derive the variation of electron density deviation over the equatorial region. Based on these measured electron density deviations and other assumed model parameters, including a three-dimensional power-law form of irregularity spectrum of index 4, a model of equatorial scintillations is developed in the framework of diffraction theory. The percentage occurrence contours of estimated equatorial scintillations greater than or equal to 4.5 dB at 140 MHz during 1900 to 2300 LMT for the period November to December 1969 and 1970 have been derived. The model is found to depict a pronounced longitude variation with the scintillation belt width and percentage occurrence being maximum over the African sector. The latitude extent of the spatial scintillation belt narrows over the American sector without much decrease in the scintillation occurrence whereas over the Indian and Far Eastern sectors both the extent and the occurrence are found to decrease. The percentage occurrence of scintillations estimated from this model is found to be consistent with VHF scintillation measurements at Ghana, Huancayo, and Calcutta. In addition, the model was found to be in qualitative agreement with GHz observations at various longitudes made by the COMSAT group. The effect of varying model parameters on scintillation estimates at VHF, UHF and GHz are discussed. Implications of the observed longitudinal variation of scintillations on current theories of equatorial irregularity formation are indicated. (Author).