Florida
Space Institute Seminar Announcement
Speaker: John Wise
Affiliation: Air Force Research Lab,
Space Weather Center of Excellence Branch of the Battlespace Environment Lab of
the Space Vehicles Directorate
Day and Date: Wednesday, September 18,
2013
Time: 11:00 - 12:00
Location:
Research Park
12354
Research Parkway
Partnership
1 Bldg. Suite 209
Orlando,
FL 32826
Title:
Empirical Modeling Of The Thermosphere
The
thermosphere is the part of our atmosphere extending from 80 km to around 600
km. It is the region in which low earth orbit (LEO) satellites
operate. Neutral density variations from the thermosphere create drag on
these satellites and affect their orbits. In order to understand how the
thermosphere affects satellite orbits we need to model its neutral density
and composition. We discuss some measurements from the Atmospheric
Density Mass Spectrometer (ADMS), which flew onboard the TacSat-2 satellite
during the last solar minimum in 2007, which collected in-situ ratios of
total oxygen/N2 in the thermosphere between 415-425 km, at various local
times and latitudes equatorward of +/- 40 degrees. The number
densities for oxygen and nitrogen were compared to the NRLMSISE-00 model and to
the mass spectrometer measurements of the OSS and NATE from Atmospheric Explorer
(AE) during the solar minimum of 1976. The ADMS atomic oxygen was
determined to be more than 50% lower than the atomic oxygen measured by AE at
400 km. During 2007 the atomic oxygen was about 50% lower than MSIS, but
the ADMS N2 densities were in reasonable agreement with the model.
ADMS did not collect data for helium so we are only able to infer its mixing
ratio based on corrected model results. We adjusted the MSIS total
density and O/N2 profiles for several local times when ADMS, CHAMP and GRACE
were co-located. The MSIS exospheric temperature and atomic oxygen
were adjusted to reduce data/model errors between the three experiments in a
least squares sense. Reasonable fits were obtained for late afternoon in
the northern hemisphere as well as midnight local times, but the dawn and
noontime cases were more difficult to model.
.For
further information please the click below:
No comments:
Post a Comment