Accession Number:

AD0661650

Title:

ELECTROMAGNETIC EFFECTS OF ATMOSPHERIC GRAVITY WAVES,

Descriptive Note:

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE GEOPHYSICS LAB

Personal Author(s):

Report Date:

1967-05-12

Pagination or Media Count:

177.0

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 meterssecond. The waves are strongly reflected by temperature gradients in the lower thermosphere. Author

Subject Categories:

  • Atmospheric Physics
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE