Detection of Solar Rotational Variability in the LYRA 190 - 222 nm Spectral Band

TL;DR

This study develops an algorithm to analyze solar spectral irradiance variability using LYRA data despite instrument degradation, comparing results with other measurements and models to understand solar rotational effects.

Contribution

The paper introduces a novel algorithm to extract solar variability from degraded LYRA data and validates it against SORCE/SOLSTICE measurements and COSI modeling.

Findings

Successful extraction of solar variability despite instrument degradation

Agreement between LYRA-based results and SORCE/SOLSTICE measurements

Validation of COSI model against observed data

Abstract

We analyze the variability of the spectral solar irradiance during the period from 7 January, 2010 until 20 January, 2010 as measured by the Herzberg channel (190-222 nm) of the Large Yield RAdiometer (LYRA) onboard PROBA2. In this period of time observations by the LYRA nominal unit experienced degradation and the signal produced by the Herzberg channel frequently jumped from one level to another. Both these factors significantly complicates the analysis. We present the algorithm which allowed us to extract the solar variability from the LYRA data and compare the results with SORCE/SOLSTICE measurements and with modeling based on the Code for the Solar Irradiance (COSI).