HR: 16:35h
AN: SA24A-02    [Abstracts]
TI: A Two-Year Study of 50-MHz Mesospheric Echoes and Winds at Jicamarca, Peru
AU: * Lehmacher, G A
EM: glehmac@clemson.edu
AF: Clemson University, Department of Physics and Astronomy, Clemson, SC 29634, United States
AU: Guo, L
AF: Clemson University, Department of Physics and Astronomy, Clemson, SC 29634, United States
AU: Kudeki, E
AF: University of Illinois, Department of Electrical and Computer Engineering, Urbana, IL 61801, United States
AU: Akgiray, A
AF: University of Illinois, Department of Electrical and Computer Engineering, Urbana, IL 61801, United States
AU: Reyes, P
AF: University of Illinois, Department of Electrical and Computer Engineering, Urbana, IL 61801, United States
AU: Chau, J
AF: Jicamarca Radio Observatory, Instituto Geofisico del Peru, Lima, Peru
AB: The Jicamarca 50-MHz radar has been operated since December 2004 for over 30 days in a MST-ISR mode receiving coherent scatter between 11 to 180 km with nominal 150 m resolution and incoherent scatter between 200 and 900 km. This paper will focus on the highly structured turbulent layers from the daytime mesosphere (D region) between 55 and 85 km. Non-linear fitting of a generalized Gaussian yields power, Doppler velocities and spectral width for four fixed beams, from which horizontal and vertical winds, momentum fluxes and turbulent velocities are calculated. The ISR data are modeled to determine electron density profiles (which are compared to ionosonde data) and also calibration factors for all beams to derive absolute reflectivities for the mesospheric turbulent scatter. Earlier experiments have shown evidence for annual and semiannual variability in the winds, signatures of the diurnal tide, inertia-gravity waves and instabilities. The more comprehensive data set covering over two years is employed to study the variability of small-scale dynamics and its correlation with the seasonal change of the prevailing winds.
DE: 3332 Mesospheric dynamics
DE: 3379 Turbulence (4490)
DE: 3389 Tides and planetary waves
DE: 6952 Radar atmospheric physics (1220)
SC: SPA-Aeronomy [SA]
MN: 2007 Joint Assembly