Open AccessForecasting solar extreme and far ultraviolet irradiance
Author(s) -
Henney C. J.,
Hock R. A.,
Schooley A. K.,
Toussaint W. A.,
White S. M.,
Arge C. N.
Publication year - 2015
Publication title -
space weather
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 56
ISSN - 1542-7390
DOI - 10.1002/2014sw001118
Subject(s) - extreme ultraviolet lithography , extreme ultraviolet , irradiance , solar irradiance , physics , sunspot , ultraviolet , solar minimum , flux (metallurgy) , solar maximum , magnetic field , astrophysics , correlation coefficient , atmospheric sciences , earth's magnetic field , wavelength , coronal mass ejection , solar cycle , optics , solar wind , chemistry , statistics , laser , mathematics , organic chemistry , quantum mechanics
A new method is presented to forecast the solar irradiance of selected wavelength ranges within the extreme ultraviolet (EUV) and far ultraviolet (FUV) bands. The technique is similar to a method recently published by Henney et al. (2012) to predict solar 10.7 cm (2.8 GHz) radio flux, abbreviated F 10.7 , utilizing advanced predictions of the global solar magnetic field generated by a flux transport model. In this and the previous study, we find good correlation between the absolute value of the observed photospheric magnetic field and selected EUV/FUV spectral bands. By evolving solar magnetic maps forward 1 to 7 days with a flux transport model, estimations of the Earth side solar magnetic field distribution are generated and used to forecast irradiance. For example, Pearson correlation coefficient values of 0.99, 0.99, and 0.98 are found for 1 day, 3 day, and 7 day predictions, respectively, of the EUV band from 29 to 32 nm. In the FUV, for example, the 160 to 165 nm spectral band, correlation values of 0.98, 0.97, and 0.96 are found for 1 day, 3 day, and 7 day predictions, respectively. In the previous study, the observed F 10.7 signal is found to correlate well with strong magnetic field (i.e., sunspot) regions. Here we find that solar EUV and FUV signals are significantly correlated with the weaker magnetic fields associated with plage regions, suggesting that solar magnetic indices may provide an improved indicator (relative to the widely used F 10.7 signal) of EUV and FUV nonflaring irradiance variability as input to ionospheric and thermospheric models.