HR: 17:30h
AN: SA14A-07    [Abstracts]
TI: The midnight temperature maximum: seasonal and solar cycle climatology
AU: Faivre, M
EM: faivre@clemson.edu
AF: Clemson University, Department of Physics and Astronomy, Clemson, SC 29634-0978 United States
AU: * Meriwether, J W
EM: john.meriwether@ces.clemson.edu
AF: Clemson University, Department of Physics and Astronomy, Clemson, SC 29634-0978 United States
AU: Biondi, M A
EM: biondi+@pitt.edu
AF: University of Pittsburgh, Department of Physics and Astronomy, Pittsburgh, PA 15268 United States
AU: Fesen, C
EM: fesen@tide.dartmouth.edu
AF: Clemson University, Department of Physics and Astronomy, Clemson, SC 29634-0978 United States
AB: Examination of the series of low-latitude thermospheric temperatures observed in the early evening between solar minimum and solar maximum with the Fabry-Perot interferometer located at Arequipa, Peru (16.5 S, 71.5 W) have shown an increase from typical values of 650-700 K to 1100-1150 K between early 1997 and mid-2000. These results represent 396 nights of temperature measurements between 0 and 9 UT. Comparison with the MSIS 00 NRL model showed generally good agreement but with frequent large deviations of 50 to 100 K illustrating the large variability of the thermospheric temperature at low latitudes. The Arequipa temperature observations were used to study the morphology of the midnight temperature maximum (MTM) which is a heating of the low-latitude thermosphere that takes place during the midnight hours and is not reproduced in the MSIS 00 model. The mean MTM amplitude was found to be typically 75 K during solar minimum and about 20 K lower at solar maximum. The peak amplitude of the MTM occurs between 06 and 08 UT during the winter solstice and between 05 to 07 near the equinoxes. The nighttime thermal variation of the MTM is well represented by a Gaussian distribution with a full width extent of 3 to 5 hours. These results display considerable variability from night to night in the amplitude and timing of the MTM appearance, which probably implies a strong degree of variability in the tidal forcing believed to be the cause of the MTM phenomenon.
DE: 0310 Airglow and aurora
DE: 0350 Pressure, density, and temperature
DE: 0358 Thermosphere--energy deposition
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting