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.