HR: 0830h
AN: SA21A-12 [Abstracts]
TI: Upper thermal boundary layer of planetary atmosphere: an experience of developing a general theory
AU: * Semenov, A
EM: asemenov@ucar.edu
AF: High Altitude Observatory,
National Center for Atmospheric Research, 3450 Mitchell Lane, Boulder, CO 80301 United States
AU: * Semenov, A
EM: asemenov@ucar.edu
AF: Institute of Physics, St.Petersburg State University, Petrodvorets, Ulyanovskaya 1, St.Petersburg,
198504 Russian Federation
AU: Shved, G
EM: shved@pobox.spbu.ru
AF: Institute of Physics, St.Petersburg State University, Petrodvorets, Ulyanovskaya 1, St.Petersburg,
198504 Russian Federation
AB:
Any planetary atmosphere has an upper layer where molecular heat conduction contributes significantly to the energy balance.
In that layer the heat from absorbed solar radiation is transferred down to the lower atmosphere where it is removed away by
the longwave radiation of atmosphere. We call that layer an upper thermal boundary layer and propose a general model for it
in terms of dimensionless variables and parameters. The values of the dimensionless parameters and relations between them
were obtained for Earth and Mars by fitting the calculated temperature profile
to the empirical one. A distinction in kind in the interrelations of the mechanisms that determine the thermal structure of
the layer is revealed for these planets, which reflects the difference in the mixing ratios of carbon dioxide in the
atmospheres of Earth and Mars to orders of
magnitude. The model consistency and accuracy is examined by an attempt to retrieve approximately the mixing ratio of atomic
oxygen in the thermosphere of Mars from the empirical temperature profile. The accelerometer data obtained by MGS spacecraft
during aerobraking are used
to derive an average temperature profile of dayside thermosphere of Mars in Northern hemisphere during spring and
intermediate (from minimum to moderate) solar activity conditions.
DE: 0358 Thermosphere--energy deposition
SC: SPA-Aeronomy [SA]
MN: 2005 Joint Assembly