Accession Number : AD0636503

Title :   TROPOSPHERIC RADIO DUCT METEOROLOGY AT VHF AND UHF IN THEORY AND AS OBSERVED ON A TRIP AROUND THE WORLD, FEBRUARY 8 TO MARCH 15, 1962.

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Randall, D. L.

Report Date : 31 MAY 1966

Pagination or Media Count : 73

Abstract : Vorticity fields showing areas of divergence or convergence in the air-mass flow channels at or above the gradient wind level may be located on a weather map and are theoretically related to the formation or dissipation of elevated radio ducts at vhf and uhf. Theoretical predictions of elevated radio duct formation have been verified by measurements made on a trip around the world, February 8 to March 15, 1962, in a Naval Research Laboratory aircraft. It was verified that ducts result from warm dry air subsiding over cooler moist air in a divergence (anticyclone) area during conditions of stable or increasing pressure. On the basis of the theory and the meteorological measurements, oceanic regions in the world most likely to support radio duct formation at different seasons of the year were mapped. For either the Northern or the Southern Hemisphere, in winter these regions are predominantly in the Torrid Zone but in summer have extended farther into the Temperate Zone and are less prevalent in the Torrid Zone. (Author)

Descriptors :   (*RADIO TRANSMISSION, *TROPOSPHERE), VERY HIGH FREQUENCY, ULTRAHIGH FREQUENCY, RADIO WAVES, PROPAGATION, ATMOSPHERIC MOTION, AIR MASS ANALYSIS, COMMUNICATION AND RADIO SYSTEMS, METEOROLOGICAL PHENOMENA

Subject Categories : Atmospheric Physics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE