Thermospheric response observed over Fritz peak, Colorado, during two large geomagnetic storms near solar cycle maximum

Journal Article · Mon Nov 01 04:00:00 EST 1982 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA087iA11p09181· OSTI ID:6559913

Hernandez, G; Roble, R G; Ridley, E C; Allen, J H

Nightime thermospheric winds and temperatures have been measured over Fritz Peak Observatory, Colorado (39.9 /sup 0/N, 105.5 /sup 0/W), with a high resolution Fabry-Perot spectrometer. The winds and temperatures are obtained from the Doppler shifts and line profiles of the (O 1) 15,867K (630 nm) line emission. Measurements made during two large geomagnetic storm periods near solar cycle maximum reveal a thermospheric response to the heat and momentum sources associated with these storms that is more complex than the ones measured near solar cycle minimum. In the earlier measurements made during solar cycle minimum, the winds to the north of Fritz Peak Observatory had an enhanced equatorward component and the winds to the south were also equatorward, usually with smaller velocities. The winds measured to the east and west of the observatory both had an enhanced westward wind component. For the two large storms near the present solar cycle maximum period converging winds are observed in each of the cardinal directions from Fritz Peak Observatory. These converging winds with speeds of hundreds of meters per second last for several hours. The measured neutral gas temperature in each of the directions also increases several hundred degrees Kelvin. Numerical experiments done with the NCAR thermospheric general circulation model (TGCM) suggest that the winds to the east and north of the station are driven by high-latitude heating and enhanced westward ion drag associated with magnetospheric convection. The cause of the enhanced poleward and eastward winds measured to the south and west of Fritz Peak Observatory, respectively, is not known. During geomagnetic quiet conditions the circulation is typically from the soutwest toward the northeast in the evening hours.

• Research Organization: Fritz Peak Observatory, Aeronomy Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80303
• OSTI ID: 6559913
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 87:A11; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640200* -- Atmospheric Physics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMBIENT TEMPERATURE
DOPPLER EFFECT
EARTH ATMOSPHERE
FABRY-PEROT INTERFEROMETER
INTERFEROMETERS
MAGNETIC STORMS
MEASURING INSTRUMENTS
NUMERICAL SOLUTION
SOLAR CYCLE
THERMOSPHERE
WIND