HR: 11:00h
AN: SA32A-03 INVITED     [Abstracts]
TI: The Effects of Variations in the Solar UV and Soft Xray Fluxes on Models of the Ionospheres/Thermospheres of the Terrestrial Planets
AU: * Fox, J L
EM: jane.fox@wright.edu
AF: Department of Physics, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435 United States
AB: In the past few years, we have had a number of different solar UV flux models available, in addition to those of Hinteregger, which were derived from Atmosphere Explorer measurements in the 1970's, and which continue to be used in some models of planetary thermospheres/ionospheres. In the decades since Atmosphere Explorer, a number of satellites have measured the solar fluxes in different wavelength regions, including several which have measured solar fluxes in the UV and X-ray regions. Because Atmosphere Explorer did not measure the solar X-ray fluxes, these measurements have greatlty advanced our knowledge of the magnitude of the fluxes in this region of the spectrum and their variability. We discuss the effects on the ionospheres/thermospheres of the terrestrial planets of adopting different solar flux spectra, including the Solar 2000 (S2K) models of K. Tobiska, which have incorporated data from recent satellites. The S2K v1.24 models incorporate the solar soft X-ray fluxes as measured by the Student Nitric Oxide Explorer (SNOE) satellite, and the S2K v2.2x models incorporate measurements from the TIMED SEE experiment. Radio occultation measurements of the electron density profiles of both Mars (made by the Mars Global Surveyor) and Venus (made by from Pioneer Venus) sometimes show lower peaks that have been ascribed to the effects of the large and variable fluxes of solar soft xrays. This contrasts with models of the Earth's ion density profiles as modeled by Solomon et al. We discuss the reasons for these differences, and the wavelength regions which must be enhanced to cause the observed low altitude peaks to form on Mars and Venus.
DE: 2419 Ion chemistry and composition (0335)
DE: 2427 Ionosphere/atmosphere interactions (0335)
DE: 2459 Planetary ionospheres (5435, 5729, 6026, 6027, 6028)
DE: 5435 Ionospheres (2459)
SC: SPA-Aeronomy [SA]
MN: 2005 Joint Assembly