Improved Aura/OMI Solar Spectral Irradiances: Comparisons With Independent Data Sets and Model Predictions

Abstract

The stability and longevity of the Ozone Monitoring Instrument (OMI), flying on board the (active) Aura Earth‐observing satellite since July 2004, facilitates creation of accurate, long‐term record of relative (normalized to a solar minimum) solar spectral irradiances (SSIs). Here we discuss technical details of the most recent version (V3) of the SSI product that provides approximately daily measurements for the period July 2006 to April 2018 in the 265‐ to 500‐nm domain with average 0.5‐nm resolution. We compare OMI SSIs with concurrent independent observations and model estimates. The short‐term (solar rotational cycle) observations and model predictions mostly agree to ∼0.1–0.2% in the ultraviolet domain, with an excellent, down to ∼0.01% agreement in the visible range. The long‐term (solar cycle) comparisons pose more challenges in the ultraviolet domain, where the differences between observations and models frequently exceed the rather conservative ∼0.1% (both point‐to‐point and long‐term) OMI uncertainties. In the visible range, these differences gradually diminish to <0.05% yet again pointing to reliability and robustness of the amassed SSI data in this domain.

Keywords

• solar variability
• solar activity cycles
• solar irradiances