Version 2 of the TSIS-1 Hybrid Solar Reference Spectrum and Extension to the Full Spectrum

This work describes two achievements to a key data set. First, we present version 2 of the Total and Spectral Solar Irradiance Sensor-1 Hybrid Solar Reference Spectrum (TSIS-1 HSRS), which has recently been recognized as a new solar irradiance reference standard (https://calvalportal.ceos.org/). Second, we present a new "full spectrum extension" of the TSIS-1 HSRS. The TSIS-1 HSRS observational composite solar irradiance reference spectrum spans 0.202-2.730 μm and encompasses more than 97% of the energy in the total solar irradiance (TSI). Version 2 is an incremental update that corrects the radiometric baseline between 0.202 and 0.210 μm and updates the solar lines at wavelengths longward of 0.743 μm to those listed in the most recent database. The full spectrum extension builds off version 2 of the TSIS-1 HSRS and supports applications that require a solar spectrum encompassing nearly 100% of the energy in the TSI. It spans 0.115-200 μm and was developed by incorporating additional observations and theoretical knowledge where no direct observations currently exist.