Vorticity and divergence in the high-latitude upper thermosphere

Journal Article · Mon Apr 01 04:00:00 EST 1991 · Geophysical Research Letters (American Geophysical Union); (United States)

DOI:https://doi.org/10.1029/91GL00131· OSTI ID:5316074

Thayer, J P ^[1]; Killeen, T L ^[2]

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1. SRI International, Menlo Park, CA (USA)
2. Univ. of Michigan, Ann Arbor (USA)

Measurements made from the Dynamics Explorer-2 satellite in November 1981 through January 1982 and November 1982 through January 1983 have been analyzed to determine the divergence and vertical component of vorticity of the high-latitude neutral wind field in the upper thermosphere for quiet (kp{le}6) geomagnetic conditions and for both northern (winter) and southern (summer) hemispheres in the polar thermosphere and provides insight into the relative strengths of the different sources of momentum and energy responsible for driving the winds. The principal findings from this work include the following: The mean neutral wind pattern is dominated by rotational flow rather than by divergent flow, with a typical vorticity: divergence ratio of {approximately} 2:1 for active conditions and {approximately} 4:1 for quiet conditions. Comparison of the divergence and vorticity patterns for quiet and active conditions indicates that the divergent component of the neutral flow intensifies more significantly with increasing geomagnetic activity than does the rotational component.

• OSTI ID: 5316074
• Journal Information: Geophysical Research Letters (American Geophysical Union); (United States), Journal Name: Geophysical Research Letters (American Geophysical Union); (United States) Vol. 18:4; ISSN GPRLA; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

640200* -- Atmospheric Physics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPARATIVE EVALUATIONS
DATA ANALYSIS
EARTH ATMOSPHERE
EARTH PLANET
EVALUATION
EXPLORER SATELLITES
F REGION
IONOSPHERE
NORTHERN HEMISPHERE
PLANETARY IONOSPHERES
PLANETS
POLAR REGIONS
SATELLITES
SOLAR CYCLE
SOUTHERN HEMISPHERE
THERMOSPHERE
VORTICES
WIND