Accession Number:

ADP002728

Title:

Ionospheric Factors Affecting the Performance of HF (High Frequency) Sky-Wave Sea-State Radars,

Descriptive Note:

Corporate Author:

RUTHERFORD AND APPLETON LABS CHILTON (ENGLAND)

Personal Author(s):

• Bradley,P. A.
• Bramley,E. N.
• Gibson,A. J.
• King,J. W.

Report Date:

1983-08-01

Pagination or Media Count:

10.0

Abstract:

This paper contains an assessment, partly theoretical and partly based on observations, of the impact of various ionospheric factors on the usefulness of the HF sky-wave sea-state radar techniques. The points discussed include the following a The ionospheric propagation modes available will not permit all parts of the ocean which it is desired to investigate to be illuminated at all times in such a way that good-quality Doppler spectra are obtained. Es-mode propagation generally results in good-quality Doppler spectra from which information about the sea waves can be inferred, but F-mode propagation yields poor spectra which can only be used to deduce the surface wind direction, b Doppler shifts associated with vertical ionospheric motions give spectral contamination which limits the amount of information that can be derived. Spectral contamination also arises under conditions of multi-mode propagation and when high- and low-angle rays are present, and c Lack of knowledge of the height of reflection of the sky-wave signals means that the area of ocean probed cannot be located accurately.

Descriptors:

• *Doppler radar
• *Ionospheric disturbances
• *Sea States
• *Ocean waves
• Wind direction
• Doppler effect
• Contamination
• Low angles
• High frequency
• Spectra
• Observation
• Oceans
• Multimode
• Surfaces
• Ionosphere
• Propagation
• Parts

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE