HR: 11:00h
AN: SM11D-03    [PDF]
TI: Hazards of Coupling Models of Different Physical and Regional Properties: Sun-Earth EUV Link
AU: * Sojka, J J
EM: fasojka@sojka.cass.usu.edu
AF: Utah State University, Center for Atmospheric and Space Sciences, 4405 Old Main Hill, Logan, UT 84322-4405 United States
AU: David, M
EM: michael@sim.cass.usu.edu
AF: Utah State University, Center for Atmospheric and Space Sciences, 4405 Old Main Hill, Logan, UT 84322-4405 United States
AU: Smithtro, C
EM: smithtro@cc.usu.edu
AF: Utah State University, Center for Atmospheric and Space Sciences, 4405 Old Main Hill, Logan, UT 84322-4405 United States
AU: Schunk, R W
EM: schunk@cc.usu.edu
AF: Utah State University, Center for Atmospheric and Space Sciences, 4405 Old Main Hill, Logan, UT 84322-4405 United States
AB: Physical models have an evolutionary heritage that includes hidden approximations, numerical limitations, as well as forgotten calibration dependencies. As new data sets become available and computer speed increases, the models evolve further and become more ambitious, often leaving their limitations even more deeply hidden. Recent progress in describing the solar extreme ultraviolet EUV spectrum has led to an increase in the number of solar EUV models available. Each has unique strengths but, unfortunately, they are significantly different. Both the ionosphere and thermosphere heavily depend on the solar EUV input for ionization and heating in the former case and heating in the latter case. Hence, the non-expert desire to test the various coupling schemes between solar EUV and ionosphere/thermosphere leads to a series of difficulties lying outside the models' calibration range. The USU Time Dependent Ionospheric Model (TDIM) was used to simulate E and F region responses to the variety of solar EUV representations. These simulations are augmented by a series of TDIM sensitivity studies of the chemical and physical processes. By understanding how sensitive the TDIM is to various drivers, it is then possible to evaluate if indeed the TDIM can uniquely determine which solar EUV representation is appropriate. This will be shown to be impossible because of the large uncertainties that are associated with the other ionospheric drivers; chemical reaction rates, neutral densities and composition, neutral winds and profile shapes, topside fluxes of both density and energy, etc. The surprising result is that by adding newer solar EUV representations, the TDIM becomes less accurate and "recalibration" is necessary.
DE: 2447 Modeling and forecasting
DE: 2479 Solar radiation and cosmic ray effects
DE: 7538 Solar irradiance
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting