Mesoscale spatial variability of lower thermospheric winds during the
Anomalous Transport Experiment (ATREX)
Abstract
The Anomalous Transport Experiment (ATREX) comprised seven
quasi-simultaneous observations of lower thermospheric winds,
horizontally separated by up to 600 km, on 27 March 2012, 0900 UT. Zonal
and meridional wind profiles were obtained with five sounding rockets
launched from Wallops Island (38 N, 75.5 W) releasing seven trimethyl
aluminum trails which were observed from three cameral sites. The wind
profiles exhibit deep coherent wave structures between 85 and 140 km,
dominated by very strong diurnal and semidiurnal tides below 120 km. The
total wind amplitude exceeds 100 m/s, three times the value from the
Global Scale Wave Model. In addition, a large scale, vertically
propagating and growing, inertia-gravity wave, most visible above 120
km, has been isolated by empirical orthogonal function analysis. The
region between 100 and 110 km shows the largest mesoscale variability of
winds and wind shears, often exceeding 40 m/s/km. We will present an
estimation of the structure function for wind fluctuations and possible
evidence for stratified mesoscale turbulence.