HR: 0830h
AN: SA41A-05    [Abstracts]
TI: Earth FUV Dayglow Response to the 20 January 2005 Solar Flare: TIMED and IMAGE Observations
AU: * Retherford, K D
EM: KRetherford@swri.edu
AF: Southwest Research Institute, 6220 Culebra Rd, San Antonio, TX 78238 United States
AU: Gladstone, R
EM: rgladstone@swri.edu
AF: Southwest Research Institute, 6220 Culebra Rd, San Antonio, TX 78238 United States
AU: Solomon, S C
EM: stans@ucar.edu
AF: National Center for Atmospheric Research / High Altitude Observatory, 3450 Mitchell Lane, Boulder, CO 80301 United States
AU: Immel, T J
EM: immel@ssl.berkeley.edu
AF: University of California Berkeley Space Sciences Laboratory, University of California, Berkeley, CA 94720 United States
AB: An X-class solar flare occurred on 20 January 2005 when the TIMED and IMAGE spacecraft were both well positioned to observe the response of Earth's dayglow emission intensity. Brightness enhancements during the flare relative to just before were determined at tangent altitudes of peak emission viewed toward the limb with TIMED. The TIMED observations were made at low solar zenith angles and show flare enhancements of roughly 15%, 30%, 30%, and 60%, respectively, for OI 130.4 nm, OI 135.6 nm, N₂ LBH Short, and N₂ LBH Long modes of the TIMED/GUVI instrument. However, GUVI observations of HI Lyman-alpha emission brightness do not show a significant brightness change. This lack of change in HI Lyman-alpha dayglow brightness is consistent with no significant change (<2%) in the solar Lyman-alpha flux observed with TIMED/SEE. Enhancements of emissions produced by photodissociation and photoelectron impact excitation sources are studied with IMAGE observations following Immel et al., JGR, 2003. Simulations of dayglow limb profiles to compare with the observations are produced using the NRLMSIS atmosphere model, the IRI90 ionosphere model, the GLOW photoelectron model, and the REDISTER radiative transfer model. The combined datasets enable a better study of the airglow sources most affected by the EUV and x-ray components of solar irradiance variability. We report our preliminary analysis of the response of FUV dayglow emissions to this event.
DE: 0310 Airglow and aurora
DE: 2423 Ionization mechanisms
DE: 2459 Planetary ionospheres (5435, 5729, 6026, 6027, 6028)
DE: 2479 Solar radiation and cosmic ray effects
DE: 7538 Solar irradiance
SC: SPA-Aeronomy [SA]
MN: 2005 Joint Assembly