Solar irridiance variations and solar activity

Journal Article · Tue Jun 01 04:00:00 EDT 1982 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA087iA06p04319· OSTI ID:6806518

Willson, R C

A mean value for the 1 AU total solar irradiance of 1368.2 W/m/sup 2/ and a downward trend of 0.05% per year were derived from measurements by the Active Cavity Radiometer Irradiance Monitor (ACRIM) experiment on the Solar Maximum Mission during 1980. Distinct temporary solar irradiance decreases associated with solar activity maxima were observed with a series of nine dips from April to October recurring at fairly regular intervals averaging 24 days. The decreases correlate inversely with sunspot area, 2800-MHz flux, and Zurich sunspot number. Dominant periods common to the irradiance and sunspot area power spectra link the irradiance decreases to sunspot flux deficit in solar active regions. Evidence of significant total irradiance modulation by facular flux excess is cited. A persistent radiative cycle of active regions consistent with the ACRIM irradiance results and the morphology of solar active regions was found. The pattern of regularly recurrent active region maxima between April and October suggests an asymmetry in solar activity generation during this period.

• Research Organization: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109
• OSTI ID: 6806518
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 87:A6; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
FLUX DENSITY
MEASURING INSTRUMENTS
RADIANT FLUX DENSITY
RADIATION DETECTORS
RADIOMETERS
SOLAR ACTIVITY
SUNSPOTS
VARIATIONS