Accession Number : ADP003900

Title :   Transhorizon Microwave Propagation Measurements Related to Surface Meteorological Parameters,

Corporate Author : BOLOGNA UNIV (ITALY)

Personal Author(s) : Ambrosini,R. ; Caporaloni,M. ; Tomassetti,G.

Report Date : FEB 1984

Pagination or Media Count : 6

Abstract : Experimental results of three months of continuous measurements at 3cm. wavelengths are given for the following aligned paths; the first, 100 Km. long, over flat land (Po Valley); the second, 140 Km, long, across the Adriatic sea; the third consisting of the sum of the previous ones. The stations are linked by radiowaves only during super standard atmospheric conditions. The period considered was in the autumn-winter season, from October to December, for 92 days of observations. Hourly efficiency istograms are drawn. They present a peculiar trend for the different paths; variable over land, with a strong maximum in the nocturnal hours; almost constant over sea, with a characteristic peak around noon for the combined path. Efficiencies up to 43% have been measured on flat land during the night, while lower values were found on the sea. An attempt to find a direct connection between radio signal reception in super standard conditions and surface meteorological parameters, has shown a strong correlation with water vapour pressure for the sea path: radio ducting sets up for a monotonic decoying of the water content of the air. Measurements over flat land show radio ducting to be almost nocturnal phenomenon. Radio propagation beyond the horizon detects temperature inversions caused by nocturnal cooling and therefore, there is not very clear evidence of correlation with ground meteorological data. (Author)

Descriptors :   *Electromagnetic wave propagation, *Microwave communications, Troposphere, Atmospheric refraction, Meteorological phenomena, Radio waves, X band, Seasonal variations, Temperature inversion, Terrain, Italy, Tropospheric scatter communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE