Solar flux variability in the Schumann-Runge continuum as a function of solar cycle 21

Journal Article · Sat Nov 01 04:00:00 EST 1980 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA085iA11p06063· OSTI ID:6735316

Torr, M R; Torr, D G; Hinteregger, H E

Measurements of the solar flux in the Schumann-Runge continuum (1350-1750 A) by the Atmosphere Explorer satellites reveal a strong dependence on solar activity. Solar intensities over the rising phase of cycle 21, increase by more than a factor of two at the shorter wavelengths (1350 A), with a smaller change (approx.10%) at 1750 A. A significant 27 day variability is found to exist superimposed on the solar cycle variation. Because radiation in this portion of the spectum is important to the lower thermosphere in the photodissociation of 0/sub 2/ and the production of 0(/sup 1/D), we use the unattenuated Schumann-Runge continuum dissociation frequency as a parameter to illustrate the magnitude and temporal characteristics of this variation. The values of this parameter, J/sub infinity/(0/sub 2/)/sub SR/, range from 1.5 x 10/sup -6/ s/sup -1/ for April 23, 1974, to 2.8 x 10/sup -6/ s/sup -1/ for February 19, 1979. In studies of oxygen in the lower thermosphere, it is therefore necessary to use solar spectral intensities representative of the actual conditions for which the calculations are made. Both the J/sub infinity/(0/sub 2/)/sub SR/ parameter and the solar flux at various wavelengths over the 1350 to 1750 A range can be expressed in terms of the F10.7 index to a reasonable approximation.

• Research Organization: Center for Atmospheric and Space Sciences, Utah State Univerity, Logan, Utah 84322
• OSTI ID: 6735316
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 85:A11; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHEMICAL REACTIONS
DECOMPOSITION
EARTH ATMOSPHERE
ELEMENTS
NONMETALS
OXYGEN
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
SCHUMANN-RUNGE BANDS
SOLAR CYCLE
SOLAR FLUX
THERMOSPHERE