Premium
Incoherent scatter observations of mesospheric dynamics at Arecibo
Author(s) -
Ganguly Suman
Publication year - 1980
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl007i005p00369
Subject(s) - mesopause , mesosphere , atmospheric sciences , energy flux , adiabatic process , incoherent scatter , gravity wave , physics , flux (metallurgy) , wavelength , geology , geophysics , gravitational wave , ionosphere , astrophysics , optics , stratosphere , astronomy , materials science , metallurgy , thermodynamics
Incoherent scatter spectral observations at Arecibo have been extended down to 59 km. For the first time vertical velocities in the mesosphere have been observed using this technique. The velocities unambiguously reveal a wavelike structure growing with height and varying in time. Above around 75 km, the vertical wavelength is around 16 km and the time period about 4 hours ± 20 minutes. Vertical velocities near 90 km were as large as 1 ms −1 and the apparent vertical energy flux was reasonably constant above 75 km. Below 75 km the energy flux was substantially lower, suggesting a mechanism where the gravity waves acquire significant energy from the diurnal tidal component trapped below the mesopause. The estimated adiabatic density and temperature changes near 90 km, estimated using simple idealized theories, were around 11%. The observed changes in spectral width were also found to be in harmony with estimated density and temperature changes to within 25%.