HR: 1330h
AN: SH12A-1162    [PDF]
TI: Solar UV and EUV Irradiance and Solar Indices
AU: * Floyd, L
EM: linton.floyd@nrl.navy.mil
AF: Interferometrics Inc., 14120 Parke Long Ct., Suite 103, Chantilly, VA 20151 United States
AU: Newmark, J
EM: newmark@midas.nrl.navy.mil
AF: E.O. Hulburt Center for Space Research, Naval Research Laboaratory, 4555 Overlook Ave., SW, Washington, DC 20375 United States
AU: Herring, L
EM: herring@susim.rnl.navy.mil
AF: Interferometrics Inc., 14120 Parke Long Ct., Suite 103, Chantilly, VA 20151 United States
AU: Cook, J
EM: cook@solphys.nrl.navy.mil
AF: E.O. Hulburt Center for Space Research, Naval Research Laboaratory, 4555 Overlook Ave., SW, Washington, DC 20375 United States
AU: McMullin, D
EM: don.mcmullin@solar.nrl.navy.mil
AF: Praxis Inc., 2200 Mill Rd., Alexandria, VA 22314 United States
AB: Studies of the solar UV (120--290~nm) spectral irradiance have shown that its variation correlates well with that of the core-to-wing ratio of the Mg~II compound absorption feature near 280~nm. The two chromospheric emission lines in the feature's core cause nearly all of the Mg~II index variation. The Mg~II index has also been shown to correlate with solar He~II emerging from the transition region. Although earlier studies appeared to show that an accurate representation of the solar Ly-$\alpha$ irradiance required the separation of the long- and short-term components of the Mg~II index, recently recalibrated measurements show that Ly-$\alpha$ also has a linear relationship with Mg~II. We analyze the solar spectral irradiance derived from SOHO EIT images roughly corresponding to coronal line emissions of Fe~IX/X, Fe~XII, and Fe~XV and find that the Mg~II index represents their variation more effectively than the more commonly used F10.7~cm flux. The long-term behavior of F10.7, Mg~II, and sunspot number are compared showing a strong divergence of the latter during the latter stages of the solar cycle~23 maximum.
DE: 7507 Chromosphere
DE: 7509 Corona
DE: 7536 Solar activity cycle (2162)
DE: 7538 Solar irradiance
DE: 7549 Ultraviolet emissions
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting