Revised solar extreme ultraviolet flux model

Abstract An extended and revised solar extreme ultraviolet irradiance model for aeronomical use during the 1990s has been developed. The extensions significantly increase the application of the SERF2 solar EUV model beyond the October 1981–April 1989 time-frame. The model can now be used from 1947 to the present for coronal EUV full-disk irradiances and from 1976 to the present for chromospheric EUV full-disk irradiances. Substantial revisions to SERF2 were made which significantly improve the ability of the model to reproduce observed 27-day and solar cycle EUV temporal variations. A multiple linear regression method is used to obtain coefficients for modelled EUV photon flux. This method allows for the inclusion of new rocket and satellite datasets into the model as they become available. The solar H Lyman-α and He I 10,830 A equivalent width measurements are used as the independent model parameters for the chromospheric irradiances while the 10.7-cm radio emission daily and 81-day running mean values are the independent parameters for the coronal and transition region irradiances. The results of the model give full-disk photon fluxes at 1 AU for 39 EUV wavelength groups and discrete lines between 1.8 and 105.0 nm for a given date. The OSO, AEROS, AE satellite datasets and six rocket datasets used in the model development are summarized, the modelling technique is described in detail, the model formulation is presented, and the comparisons of the model to the datasets are discussed.

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