Seasonal variations in the equatorial thermospheric wind measured at Arequipa, Peru

Technical Report · Wed Aug 01 04:00:00 EDT 1990

OSTI ID:6101205

Biondi, M A; Merriwether, J W; Fejer, B G; Gonzalez, S A

Studies have been carried out Arequipa, Peru, of the seasonal variations in the thermospheric winds at moderate solar flux levels and geomagnetic activity. Fabry-Perot interferometer measurements of the doppler shifts in the 630.0 nm nightglow emission line from March to August 1983 and from April to October 1988 have yielded monthly-average meridional winds that are nearly zero (<50 m/s) and possible fluctuating in direction through much of the night but develop a southward flow at 50 - 100 m/s in the early and the late night from May onward. The average zonal winds are eastward throughout the night, reaching peak velocities before local midnight and then decreasing. The peak velocities increase to a maximum around the June solstice. The winds are generally stronger in 1988 than in 1983, even thought the solar EUV fluxes are comparable fro both years. Comparison of the present results with earlier satellite measurements, as embodied in the Horizontal Wind Model of Hedin et al., reveals generally satisfactory agreement at the equinox and June solstice, except for the June 1988 period. NCAR Therospheric General Circulation Model, calculated for similar solar flux levels, yields meridional and zonal wind variations which exhibit the same temporal behaviors but generally smaller values than the present measurements.

• Research Organization: Air Force Geophysics Lab., Hanscom AFB, MA (USA)
• OSTI ID: 6101205
• Report Number(s): AD-A-227370/4/XAB; FL-TR--90-0232
• Country of Publication: United States
• Language: English

Related Subjects

640200* -- Atmospheric Physics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AIRGLOW
COMPARATIVE EVALUATIONS
DEVELOPING COUNTRIES
DOPPLER EFFECT
EARTH ATMOSPHERE
EMISSION SPECTRA
FABRY-PEROT INTERFEROMETER
FLUX DENSITY
GEOMAGNETIC FIELD
INTERFEROMETERS
LATIN AMERICA
MAGNETIC FIELDS
MEASURING INSTRUMENTS
ORIENTATION
PERU
RADIATIONS
SATELLITES
SEASONAL VARIATIONS
SOLAR RADIATION
SOUTH AMERICA
SPECTRA
STELLAR RADIATION
THERMOSPHERE
VARIATIONS
VELOCITY
WIND