Sondrestrom incoherent scatter radar observations during the lower thermosphere coupling study: September 21-26, 1987

Journal Article · Fri Feb 01 04:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JA01803· OSTI ID:5223994

Johnson, R M ^[1]

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1. Univ. of Michigan, Ann Arbor (USA)

The incoherent scatter radar located at Soendre Stroemfjord, Greenland, obtained E and F region measurements during the first Lower Thermosphere Coupling Study (LTCS 1), September 21-26, 1987. Lower thermospheric neutral winds deduced from these measurements show that the neutral dynamics are influenced by both tidal oscillations and magnetospheric forcing. During an interval which was relatively quiet geomagnetically, September 23-24, a semidiurnal oscillation dominated the neutral motion. The model equinox tidal amplitudes and phases of Forbes (1982) for the diurnal tide are roughly in agreement with the observed diurnal oscillation for the first four days of the experiment. Vertical variations in the observed diurnal phases are consistent with the results of Forbes and Hagan (1988) and may provide evidence of dissipation of the propagating (1, 1) tidal mode. The semidiurnal motion observed during this period is not well represented by the recent theoretical results for the amplitude and phase of the semidiurnal tide (Forbes and Vial, this issue). Neutral winds obtained during a geomagnetically active interval, September 25-26, displayed a flow pattern that was significantly distorted from that observed during the preceding, relatively quiet interval. Although the changes in the zonal winds throughout this active interval were consistent with the direction of the ion drag force at 115 km and above, the variations in the meridional winds suggest that other forces, such as pressure gradients driven by Joule heating, need to be considered to explain the observations.

• OSTI ID: 5223994
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:A2; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640200* -- Atmospheric Physics
640201 -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATOM COLLISIONS
COLLISIONS
DATA ANALYSIS
DENSITY
DYNAMICS
E REGION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC HEATING
ELECTRON DENSITY
ELECTRON TEMPERATURE
F REGION
GRAVITY WAVES
HEATING
ION COLLISIONS
ION TEMPERATURE
ION-ATOM COLLISIONS
IONIC COMPOSITION
IONIZATION
IONOSPHERE
JOULE HEATING
MEASURING INSTRUMENTS
MECHANICS
PHYSICAL PROPERTIES
PLANETARY IONOSPHERES
PLASMA HEATING
PRESSURE GRADIENTS
RADAR
RANGE FINDERS
RESISTANCE HEATING
THERMOSPHERE
TIDE
VARIATIONS
WIND