HR: 16:45h
AN: SA14A-04    [Abstracts]
TI: The Semiannual Thermospheric Density Variation From 1970 to 2002 Between 200-1100 km
AU: * Bowman, B R
EM: bruce.bowman@peterson.af.mil
AF: Bruce R Bowman, Air Force Space Command/XPY 150 Vandenberg St. Suite 1105 AB: This study characterizes the semiannual thermospheric density variation over the last three solar cycles, covering the height range of 200 to 1100 km. Historical radar observational data have been processed with special orbit perturbations on 13 satellites with perigee heights ranging from 200 to 1100 km. The semiannual variation has been found to be extremely variable from year to year. The magnitude of the maximum yearly difference, from the July minimum to the October maximum, is used to characterize the yearly semiannual variability. It has been found that this maximum difference can vary by as much as 100 percent from one year to the next. A high correlation has been found between this maximum difference and solar EUV data. The semiannual variation for each year has been characterized based on analyses of annual and semiannual cycles.
DE: 3369 Thermospheric dynamics (0358)
DE: 0358 Thermosphere--energy deposition
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting