A numerical modeling study of the interaction between the tides and the circulation forced by high-latitude plasma convection
- Danish Meteorological Inst., Copenhagen (Denmark)
- Kyoto Univ. (Japan)
A spectral, time-varying thermospheric general circulation model has been used to study the nonlinear interaction at high latitudes between the tides propagating into the thermosphere from below and the circulation induced by magnetospheric forcing and in situ solar heating. The model is discrete in the vertical with 27 layers spaced by half a scale height. In the horizontal, the fields are expanded in a series of spherical harmonics using a triangular truncation at wave number 31, equivalent to a homogeneous global resolution with a minimum wavelength of 1,270 km. A hypothetical uniform grid point model would require a horizontal spacing of 417 km to describe the same minimum wavelength. In the high-latitude F region the tides affect the dusk vortex of the neutral flow very little, but the dawn vortex is either suppressed or amplified dependent upon the universal time and tidal phase. In the E region neutral flow, both the dusk and dawn vortices are shifted in local time by the tides, again as a function of universal time and tidal phase. At dusk a nonlinear amplification of the sunward winds occurs for certain combination of parameters, and at dawn the winds may be completely suppressed. Below 120 km altitude the magnetospheric forcing creates a single cyclonic vortex which is also sensitive to the high-latitude tidal structure.
- OSTI ID:
- 6104544
- 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
GENERAL CIRCULATION MODELS
DYNAMICS
E REGION
EARTH MAGNETOSPHERE
F REGION
INTERACTIONS
NONLINEAR PROBLEMS
SOLAR HEATING
SPHERICAL HARMONICS
TIDE
EARTH ATMOSPHERE
HEATING
IONOSPHERE
MATHEMATICAL MODELS
MECHANICS
PLANETARY IONOSPHERES
661320* - Auroral
Ionospheric
& Magnetospheric Phenomena- (1992-)