Climatologies of nighttime upper thermospheric winds measured by ground-based Fabry-Perot interferometers during geomagnetically quiet conditions: 1. Local time, latitudinal, seasonal, and solar cycle dependence

• Published in: Journal of Geophysical Research - Space Physics Vol. 111; no. A12; pp. A12302 - n/a
• Main Authors: Emmert, J. T., Faivre, M. L., Hernandez, G., Jarvis, M. J., Meriwether, J. W., Niciejewski, R. J., Sipler, D. P., Tepley, C. A.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Geophysical Union 01-12-2006; Blackwell Publishing Ltd
• Subjects: Atmospheric Processes; Climatology; Earth sciences; Earth, ocean, space; Exact sciences and technology; Fabry-Perot winds; General circulation; Ionosphere; Ionosphere/atmosphere interactions; thermosphere; Thermospheric dynamics; South Pole; Antarctica; climatology; Fabry-Perot winds; thermosphere; Interplanetary magnetic field; High latitude; Climatology; Thermosphere; Wind field; Intraseasonal variation; latitude; Nightglow; Wind velocity; Geomagnetic equator; Red line; Semiannual variation; Doppler shift; saturation; Winter; extreme value; Fabry Pérot interferometer; Neutral wind; hills; polar regions; solar cycles; irradiance; Radio flux
• ISSN: 0148-0227; 2156-2202
• DOI: 10.1029/2006JA011948

We analyze ground‐based Fabry‐Perot interferometer observations of upper thermospheric (∼250 km) horizontal neutral winds derived from Doppler shifts in the 630.0 nm (red line) nightglow. The winds were measured over the following locations: South Pole (90°S), Halley (76°S, 27°W), Arequipa (17°S, 72°W), Arecibo (18°N, 67°W), Millstone Hill (43°N, 72°W), Søndre Strømfjord (67°N, 51°W), and Thule (77°N, 68°W). We derive climatological quiet time (Kp < 3) wind patterns as a function of local time, solar cycle, day of year, and the interplanetary magnetic field (IMF), and provide parameterized representations of these patterns. At the high‐latitude stations, and at Arequipa near the geomagnetic equator, wind speeds tend to increase with increasing solar extreme ultraviolet (EUV) irradiance. Over Millstone Hill and Arecibo, solar EUV has a negative effect on wind magnitudes. As represented by the 10.7 cm radio flux proxy, the solar EUV dependence of the winds at all latitudes is characterized by a saturation or weakening of the effect above moderate values (F10.7 > 150). The seasonal dependence of the winds is generally annual, but there are isolated cases in which a semiannual variation is observed. Within the austral winter, winds measured from the South Pole show a substantial intraseasonal variation only along longitudes directed toward the magnetic pole. IMF effects are described in a companion paper.