hide
Free keywords:
solar irradiance
solar variability
Abstract:
We propose a simple model that computes the spectral profile of the solar irradiance in the hydrogen Lyman alpha line, H Ly‐α (121.567 nm), from 1947 to present. Such a model is relevant for the study of many astronomical environments, from planetary atmospheres to interplanetary medium. This empirical model is based on the SOlar Heliospheric Observatory/Solar Ultraviolet Measurement of Emitted Radiation observations of the Ly‐α irradiance over solar cycle 23 and the Ly‐α disk‐integrated irradiance composite. The model reproduces the temporal variability of the spectral profile and matches the independent SOlar Radiation and Climate Experiment/SOLar‐STellar Irradiance Comparison Experiment spectral observations from 2003 to 2007 with an accuracy better than 10%.