Thermosphere-ionosphere coupling: An experiment in interactive modeling

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA095iA01p00201· OSTI ID:5180449

Forbes, J M ^[1]; Roble, R G ^[2]

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1. Boston Univ., MA (United States)
2. National Center for Atmospheric Research, Boulder, CO (United States)

The National Center for Atmospheric Research thermosphere general circulation model (TGCM) is utilized to perform a series of controlled experiments aimed at better understanding the interactive coupling between ionospheric plasma densities and thermospheric neutral winds. The experiments are simple and controlled so as to facilitate identification of governing mechanisms. The interaction is accomplished by parameterizing the F layer peak height (h{sub m}F{sub 2}) in an empirical ionospheric model in terms of the meridional wind ({upsilon}{sub south}) and forcing h{sub m}F{sub 2} and {upsilon}{sub south} to remain mutually coupled in a dynamical calculation. Interactive computations are performed where the TGCM is driven by 30-kV and 90-kV cross polar cap potentials and are compared with corresponding reference simulations where h{sub m}F{sub 2} is constrained to a balance height near 280 km with a small ({approximately}20 km) diurnal variation. Mutual coupling between h{sub m}F{sub 2} and {upsilon}{sub south} is found to be weak during the daytime when the F layer exhibits a broad vertical structure. At night, when the F{sub 2} layer is more localized, the neutral dynamical structure is dependent on whether h{sub m}F{sub 2} is significantly above or below the altitude (approximately 275-300 km) at which ion drag effectively competes with viscosity in the neutral momentum balance. At Arecibo during both levels of high-latitude forcing, the premidnight elevation (+75 km) of h{sub m}F{sub 2} relative to a nighttime balance height of approximately 290 km is accompanied by an increase ({approximately}50 m s{sup {minus}1}) in the zonal wind above 250 km relative to the noninteractive simulation. A much smaller effect, characterized by an 8-hour periodicity spanning 24 hours, is seen in the meridional wind component.

• OSTI ID: 5180449
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:A1; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPARATIVE EVALUATIONS
DAILY VARIATIONS
DIMENSIONS
EARTH ATMOSPHERE
EVALUATION
F REGION
GENERAL CIRCULATION MODELS
HEIGHT
INTERACTIONS
IONOSPHERE
MATHEMATICAL MODELS
PLANETARY IONOSPHERES
PLASMA DENSITY
POLAR REGIONS
THERMOSPHERE
VARIATIONS
VIRTUAL HEIGHT
WIND