Open AccessShort‐term relationship between solar irradiances and equatorial peak electron densities
Author(s) -
Wang X.,
Eastes R.,
Reinisch B. W.,
Bailey S.,
Valladares C. E.,
Woods T.
Publication year - 2007
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2006ja012128
Subject(s) - noon , thermosphere , irradiance , atmospheric sciences , morning , earth's magnetic field , solar irradiance , ionosphere , solar rotation , environmental science , solar maximum , diurnal temperature variation , physics , solar cycle , astrophysics , solar physics , astronomy , optics , solar wind , quantum mechanics , magnetic field
The short‐term relationship of the equatorial peak electron density and the solar short‐wavelength irradiance is examined using foF2 observations from Jicamarca, Peru and recent solar irradiance measurements from satellites. Solar soft X‐ray measurements from both the Student Nitric Oxide Explorer (SNOE) (1998–2000) and Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) (2002–2004) satellites as well as extreme ultraviolet (EUV) measurements from the TIMED satellite are used. Soft X‐rays show similar or higher correlation with foF2 at short timescales (27 days or less) than EUV does, although the EUV correlation is higher for longer periods. For the short‐term variations, both SNOE and TIMED observations have a higher correlation in the morning (∼0.46) than in the afternoon (∼0.1). In the afternoon, SNOE observations have a higher correlation (∼0.2) with foF2 than the TIMED observations (∼0.1 correlation), which may be due to differences in the solar cycle. At morning times, foF2 has a ∼27‐day variation, consistent with the solar rotation rate. After noon, but not in the morning, a ∼13.5‐day variation consistently appears in foF2. This ∼13.5‐day variation is attributed to geomagnetic influences.