HR: 1340h
AN: SA43A-1083    [Abstracts]
TI: Simultaneous MLT and Thermospheric F-region Observations and Modeling
AU: * Nanan, B
EM: B.Nanan@sheffield.ac.uk
AF: University of Sheffield, Automatic Control and Systems Engineering, Mappin Street, Sheffield, S1 3JD United Kingdom
AU: Kawamura, S
SA43A-1083 AF: NICT, 4-2-1 Nakui Kitamachi, Tokyo, 184-8795 Japan
AU: Aylward, A
SA43A-1083 AF: University College, London, APL, UCL, London, W1W 7EJ United Kingdom
AU: Nakamura, T
SA43A-1083 AF: Kyoto University, RISH, Uji, Kyoto, 611-0011 Japan
AU: Yamamoto, M
SA43A-1083 AF: Kyoto University, RISH, Uji, Kyoto, 611-0011 Japan
AU: Fukao, S
SA43A-1083 AF: Kyoto University, RISH, Uji, Kyoto, 611-0011 Japan
AU: Alleyne, H
SA43A-1083 AF: University of Sheffield, Automatic Control and Systems Engineering, Mappin Street, Sheffield, S1 3JD United Kingdom
AB: Abstract: The mesosphere lower-thermosphere (MLT) region and thermospheric F region (upper thermosphere and ionosphere together) at mid latitudes are observed simultaneously by operating the MU radar (35°N, 136°E) in alternate meteor and incoherent scatter (IS) modes for the first time. The continuous observations, each lasting more than a week, provide simultaneous zonal and meridional wind velocities at MLT altitudes (75-95 km), meridional wind velocity in the upper thermosphere (220-450 km), and electron density, peak height and plasma drift velocity in the ionosphere, with a time resolution of 1.5 hours. The data obtained from the first simultaneous observations in October 2000 are compared with those modeled using the new version of the non-linear Coupled Thermosphere Ionosphere Plasmasphere (CTIP) model. The CTIP has lower altitude boundary at 80 km where diurnal and semi-diurnal tidal forcing are introduced using the Hough modes (1,1), (2,2), (2,3), (2,4) and (2,5), and also includes a model for the electrodynamic coupling between the ionosphere and thermosphere. The data collected at March and September equinoxes (2000-01) are also used to compare the equinoctial similarities and differences in mean winds, tides and waves. The resultant horizontal mean wind (resultant of the strong zonal mean wind and weak meridional mean wind) in the MLT region is predominantly eastward at both equinoxes. However, the eastward mean flow at September equinox is more than three times faster compared to that at March equinox, especially in the upper mesosphere (75-86 km). The meridional mean flow in the lower and upper thermospheres is equatorward at March equinox and poleward at September equinox. The diurnal (24-hour) tide is found to grow with altitude all through the MLT region at March equinox whereas at September equinox the tide grows up to mesopause (86 km) beyond which semi-diurnal (12-hour) tide grows strong. Waves of periods 16-20 and 40-60 hours exist centered at mesopause at both equinoxes, with the 16-20 hour wave being strong at March equinox and 40-60 hour wave being strong at September equinox. The tides and waves show small equinoctial differences in the upper thermosphere.
DE: 0342 Middle atmosphere: energy deposition (3334)
DE: 0358 Thermosphere: energy deposition (3369)
DE: 0394 Instruments and techniques
DE: 2437 Ionospheric dynamics
DE: 2447 Modeling and forecasting
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005