Accession Number : ADP006131

Title :   Wave-Tilt Sounding of Tropospheric Ducts above the Sea,

Corporate Author : THESSALONIKI UNIV SALONIKA (GREECE)

Personal Author(s) : Chrissoulidis, D. P. ; Kriezis, E. E.

Report Date : MAY 1987

Pagination or Media Count : 10

Abstract : The possibility to detect tropospheric ducts above the sea through airborne wave-tilt measurements is investigated in this work. Sea roughness and tropospheric refractivity anomalies associated with the presence of ducts are incorporated in an iterative procedure resulting in wave-tilt versus frequency diagrams at some altitude above sea level. In general, the diagram corresponding to ducting conditions appears shifted by Delta with respect to the diagram of the standard troposphere. This frequency shift is rather insensitive to variations of sea state, duct thickness and optimum coupling height. It is though strongly dependent on duct intensity Delta. The diagram Delta vs. Delta is not far from linear in the VHF band thus offering itself for Delta estimation through Delta measurements.

Descriptors :   *ELECTROMAGNETIC WAVE PROPAGATION, OVER THE HORIZON DETECTION, MARINE ATMOSPHERES, VERY HIGH FREQUENCY, RADIO TRANSMISSION, OCEAN SURFACE, ELECTROMAGNETIC WAVE REFLECTIONS, REFRACTION, HUMIDITY, GREECE, SYMPOSIA.

Subject Categories : Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE