Accession Number : AD0661650

Title :   ELECTROMAGNETIC EFFECTS OF ATMOSPHERIC GRAVITY WAVES,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE GEOPHYSICS LAB

Personal Author(s) : Claerbout,Jon F.

Report Date : 12 MAY 1967

Pagination or Media Count : 177

Abstract : Continuous observations of pressure fluctuations at gravity wave periods (5-30 minutes) in eastern Massachusetts show that the only important pressure fluctuations not associated with moving weather sources are fluctuations associated with the jet stream. These fluctuations appear to be non-dispersive and move a little slower than the maximum overhead jet stream velocity. The coupling between gravity wave modes and fluctuations in the jet stream is examined to investigate the pumping of energy from the jet stream into the upper atmosphere. The energy flux emitted from the critical altitude where the velocity of the disturbance matches the velocity of the mean wind is amplified by the wind shear as the wave moves away from the critical height. A wave packet moving into a critical zone becomes so compressed before it reaches the critical altitude that the wind shear within the wave itself causes the atmosphere to become locally unstable. Typical energy propagation to the ionosphere D-region (80 km.) takes 10 hours where amplitudes will be 10 meters/second. The waves are strongly reflected by temperature gradients in the lower thermosphere. (Author)

Descriptors :   (*ATMOSPHERES, GRAVITY), (*GRAVITY, *ELECTROMAGNETIC PROPERTIES), VELOCITY, ACOUSTICS, IONOSPHERE, WIND, PRESSURE, IONOSPHERIC PROPAGATION, SCATTERING, PARTIAL DIFFERENTIAL EQUATIONS, ENERGY, CONDUCTIVITY, MOMENTUM, MATHEMATICAL ANALYSIS

Subject Categories : Atmospheric Physics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE