Creation of the GSFCSSI2 Composite Solar Spectral Irradiance Data Set

Abstract

Abstract Solar spectral irradiance (SSI) is a key driver for the Earth's energy budget. Characterizing the spectral and temporal variations in SSI from measurements over multiple decades relies on the creation of a composite SSI product that merges data from multiple instruments. The V1 composite SSI product created by DeLand and Cebula (2008, https://doi.org/10.1029/98JD01204) provides daily spectra covering 120–400 nm by combining data from six instruments but ends in July 2005. We have developed an improved composite SSI product, designated GSFCSSI2, that extends to the present by incorporating additional SSI data sets from the NOAA‐16 SBUV/2, Aura Ozone Monitoring Instrument (OMI), and SORCE SOLSTICE instruments. The NOAA‐16 SBUV/2 SSI data set is a new product that fills a data gap at 170–400 nm in 2005–2006, while the Aura OMI SSI data set represents an improvement over previously published measurements and covers the time period 2006–2018. The SORCE SOLSTICE SSI data set provides data coverage down to 120 nm for the time period 2005–2018. The new GSFCSSI2 composite now spans almost 40 years (November 1978–April 2018) and extends observational coverage into the visible region (500 nm) with OMI data. Comparisons with the NRLSSI2 modelled SSI data set show typical agreement to within ±5% between 120 and 170 nm, ±2%–3% between 170 and 300 nm, and ±1.5% or better between 300 and 500 nm. The GSFCSSI2 composite SSI product is an element of the NASA Solar Irradiance Science Team program and can be further improved by incorporating other data sets being produced through that effort.

Keywords

• solar spectral irradiance