Lower thermospheric neutral densities determined from Soendre Stroemfjord incoherent scatter radar during LTCS 1
- Univ. of Michigan, Ann Arbor (USA)
Ion-neutral collision frequencies determined from measurements obtained by the incoherent scatter radar located at Soendre Stroemfjord, Greenland, have been used to derive lower thermospheric neutral densities during the first Lower Thermosphere Coupling Study (LTCS 1), September 21-26, 1987. Periods of Joule and particle heating which might disturb the E region thermal equilibrium were systematically eliminated. The mean profile of neutral density for the period is in good agreement with the mass spectrometer incoherent scatter 1986 (MSIS-86) model between 92 and 104 km. A tendency to overestimate collision frequencies above 105 km may arise from range-smearing effects. The results of a tidal analysis performed on the neutral density between 92 and 109 km show that the amplitudes of the diurnal and semidiurnal components of the tides are approximately equivalent. The observations are generally in better agreement with the MSIS-86 predictions than with the thermosphere-ionosphere general circulation model (TIGCM) simulation of the LTCS 1 interval. The observed phase of the diurnal component is approximately constant with height above 98 km and is in close agreement with the MSIS-86 model phases; however, the TIGCM diurnal phases are shifted by 6-8 hours to later local times. The phase of the semidiurnal tide is in good agreement with predictions of the MSIS-86 model and the TIGCM simulation of this interval, except near 98 km. The observed semidiurnal phase is also consistent with previous high-latitude results (Kirkwood, 1986). The relative amplitude of the observed semidiurnal oscillation is up to 15% larger than that previously observed at the European Incoherent Scatter facility but is consistent with the amplitudes presented in an earlier study of Millstone Hill measurements (Salah, 1974).
- OSTI ID:
- 5224211
- Journal Information:
- Journal of Geophysical Research; (United States), Vol. 96:A2; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
THERMOSPHERE
ION-ATOM COLLISIONS
CHEMICAL COMPOSITION
COMPARATIVE EVALUATIONS
DATA ANALYSIS
DYNAMICS
E REGION
ELECTRON DENSITY
GENERAL CIRCULATION MODELS
GRAVITY WAVES
IONOSPHERE
JOULE HEATING
MASS SPECTROMETERS
RADAR
TIDE
ATOM COLLISIONS
COLLISIONS
EARTH ATMOSPHERE
ELECTRIC HEATING
EVALUATION
HEATING
ION COLLISIONS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MECHANICS
PLANETARY IONOSPHERES
PLASMA HEATING
RANGE FINDERS
RESISTANCE HEATING
SPECTROMETERS
640200* - Atmospheric Physics