Reflection of radio waves from undulating tropospheric layers

Waterman, Alan T.; Strohbehn, John W.

doi:10.6028/jres.067d.066

Cited by 6 publications

(5 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One possible explanation is that reflections from an airplane beat with the scattered signal. However, such rapid fading is possible from certain types of layer formations in the troposphere [Waterman and Strohbehn, 1963].…”

Section: Analysis Of Experimental Angular Response Patternsmentioning

confidence: 99%

Transhorizon Propagation Measurements From a Simultaneous; Frequency and and Angle Scan Experiment

Strohbehn¹,

Waterman²

1966

Radio Science

View full text Add to dashboard Cite

An analysis of data from three sets of experiments in transhorizon microwave propagation is presented. In each set, a 3‐Gc/s signal was transmitted over a 163‐km path, and the wave arriving at the receiver was examined using a rapidly scanning phased‐array antenna. In one mode of operation, transmitter and receiver were synchronously swept over a 20‐Mc/s frequency band. The results show considerable variability in all quantities derived from the data. Received power patterns on occasions were scarcely broader than the receiving antenna pattern and at other times showed considerable power arriving off the great‐circle bearing. A classification of such patterns into "stable” and “ unstable” showed no strong association with time of day. Signal level distributions were often, but by no means always, of the Rayleigh form. The time lag required for the signal autocorrelation to drop to 0.5 — indicative of fading period — varied from a half second to a few seconds. A similar measure of transmissable bandwidth — in terms of frequency correlation — showed a variability from 1 or 2 Mc/s to more than 20. The interrelationship between all these quantities, and their connection with meteorological parameters, showed interesting individual relationships but no clear‐cut overall pattern, except for a general increase in signal level associated with pronounced inversions. In comparison with various atmospheric models, it becomes obvious that no single simple model is sufficient. On some occasions the received signal showed characteristics predicted from the theory of incoherent scatter by turbulent eddies: distorted angular response patterns with an average beam broadening, Rayleigh‐type signal level distribution, a modest fading rate, and limited transmissable bandwidth. On other occasions, the records showed evidence of marked atmospheric stability and stratification: unbroadened and undistorted antenna response patterns, a more restricted and non ‐ Rayleigh signal level distribution, variable fading rates, and extremely wide bandwidths. There are still other cases where these associations are not well defined.

show abstract

Section: Analysis Of Experimental Angular Response Patternsmentioning

confidence: 99%

Transhorizon Propagation Measurements From a Simultaneous; Frequency and and Angle Scan Experiment

Strohbehn¹,

Waterman²

1966

Radio Science

View full text Add to dashboard Cite

show abstract

“…Gerks and Anderson [1965], treating the identical problem, conclude that internal reflections cannot give high transhorizon fields. Waterman and Strohbehn [1963] postulate a horizontal layer on which is superimposed a slight wave motion, and investigate the propagation characteristics which result. Strohbehn and Waterman [1964] set up models for simulation of coherent layer and turbulent scattering and obtain variations similar to experimental observations.…”

Section: Scattering Mechanismsmentioning

confidence: 99%

U.S.A. National Committee Report, Fifteenth URSI General Assembly, Munich, September 1966: Commission 2, Radio Propagation in Nonionized Media; Progress in Radio Propagation in Nonionized Media

Katz¹,

Ament²,

Atlas³

et al. 1966

Radio Science

View full text Add to dashboard Cite

In 1965 there was a strong reawakening of interest in “angel” or clear‐air radar echoes. Atlas [1965] postulated that "dot" or point‐like angles were reflections from smooth, sharp boundaries at the apex of convective thermals. Focusing from the curved surface reduced the requirement on the index gradient to 1 N unit through 1 em; however, the requirement of smoothness to a fraction of a em over the first Fresnel zone is still severe and lacks experimental confirmation. Dot angel activity at night requires another explanation. Hardy, Atlas, and Glover [1966] and Deam and LaGrone [1965] conclude that dot angel characteristics are explainable only if the targets are insects. These conclusions stem from considerations of absolute cross section and wavelength dependence.

show abstract

“…Historically, effects of tilted fine-scale atmospheric layers have also been studied for radar propagation parallel, not perpendicular, to the layers (Waterman and Strohbehn 1963), with applications to line-of-sight microwave links. Effects of tilted specular scatterers are considered also by Metcalf and Atlas (1973) and Metcalf (1975), for FM-CW radar.…”

Section: Introductionmentioning

confidence: 99%

Asymmetry of atmospheric microstructure over synoptic scales

Worthington

2001

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. Distortions are often seen in the angular distribution of echo-power from VHF wind-profiling radars, suggesting that thin stable layers, within the air flow, are distorted and tilted from horizontal. In vertical shear of the horizontal wind, the distribution of the layer tilt angles becomes skewed. A case study using six days of VHF radar data and synoptic charts above western Europe indicates that this asymmetry of atmospheric microstructure can exist throughout the troposphere and lower stratosphere, above and below the jet wind maximum, over horizontal scales of thousands of kilometres.

show abstract

Reflection of radio waves from undulating tropospheric layers

Cited by 6 publications

References 1 publication

Transhorizon Propagation Measurements From a Simultaneous; Frequency and and Angle Scan Experiment

Transhorizon Propagation Measurements From a Simultaneous; Frequency and and Angle Scan Experiment

U.S.A. National Committee Report, Fifteenth URSI General Assembly, Munich, September 1966: Commission 2, Radio Propagation in Nonionized Media; Progress in Radio Propagation in Nonionized Media

Asymmetry of atmospheric microstructure over synoptic scales

Contact Info

Product

Resources

About