HR: 0800h
AN: SA31A-0335    [Abstracts]
TI: High Latitude Transonic Thermospheric Winds - Observation and Modelling Study
AU: * Balthazor, R
EM: r.balthazor@shef.ac.uk
AF: Space and Upper Atmosphere Research Group, Department of Applied Maths, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH United Kingdom
AB: DE 2 Wind And Temperature Spectrometer (WATS) instrument data has been reanalysed to investigate transonic excursions of the measured neutral wind. Nearly 500 supersonic events have been identified, with the zonal component of the neutral wind Mach number M in the range 1 < M < 2. These events are located in the polar cap, predominantly between 75 and 85 degrees MLT in the dawn sector. The events are located broadly spread over the height range 300 - 600 km. The mean horizontal linear extent of the regions of supersonic flow is estimated to be around 140 km. We find an anticorrelation between Mach number (for 1 < M < 2) and neutral temperature. We discuss these results in the context of a modelling study of the events using the Sheffield Coupled Thermosphere Ionosphere Plasmasphere model and first principles modelling. An instrumentation study to further investigate the fine-scale properties of supersonic flows is proposed.
DE: 2407 Auroral ionosphere (2704)
DE: 2427 Ionosphere/atmosphere interactions (0335)
DE: 2494 Instruments and techniques
DE: 2499 General or miscellaneous
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005