UV solar irradiance in observations and the NRLSSI and SATIRE-S models

Abstract

Total solar irradiance and UV spectral solar irradiance have been monitored since 1978 through a succession of space missions. This is accompanied by the development of models aimed at replicating solar irradiance by relating the variability to solar magnetic activity. The NRLSSI and SATIRE-S models provide the most comprehensive reconstructions of total and spectral solar irradiance over the period of satellite observation currently available. There is persistent controversy between the various measurements and models in terms of the wavelength dependence of the variation over the solar cycle, with repercussions on our understanding of the influence of UV solar irradiance variability on the stratosphere. We review the measurement and modelling of UV solar irradiance variability over the period of satellite observation. The SATIRE-S reconstruction is consistent with spectral solar irradiance observations where they are reliable. It is also supported by an independent, empirical reconstruction of UV spectral solar irradiance based on UARS/SUSIM measurements from an earlier study. The weaker solar cycle variability produced by NRLSSI between 300 and 400 nm is not evident in any available record. We show that although the method employed to construct NRLSSI is principally sound, reconstructed solar cycle variability is detrimentally affected by the uncertainty in the SSI observations it draws upon in the derivation. Based on our findings, we recommend, when choosing between the two models, the use of SATIRE-S for climate studies.

References in corpus (6)

• Solar cycle variation in solar irradiance
• NLTE model calculations for the solar atmosphere with an iterative treatment of opacity distribution functions
• A new SATIRE-S spectral solar irradiance reconstruction for solar cycles 21--23 and its implications for stratospheric ozone
• Solar cycle indices from the photosphere to the corona: measurements and underlying physics
• Modelling solar irradiance variability on time scales from minutes to months
• Analysis and modeling of solar irradiance variations

Cited by in corpus (6)

• Readdressing the UV solar variability with SATIRE-S: non-LTE effects
• Predictions of astrometric jitter for Sun-like stars. I. The model and its application to the Sun as seen from the ecliptic
• Revisiting the SATIRE-S irradiance reconstruction: Heritage of Mt Wilson magnetograms and Ca II K observations
• Detectability of Solar Rotation Period Across Various Wavelengths
• Reconstruction of total solar irradiance variability as simultaneously apparent from Solar Orbiter and Solar Dynamics Observatory
• Solar Spectral Irradiance Variability in Cycle 24: Observations and Models