TSIS-1 SIM L3 V05 Solar Spectral Irradiance

NASA’s Total and Spectral Solar Irradiance Sensor-1 (TSIS-1) operates on the International Space Station. TSIS-1 provides absolute measurements of the total solar irradiance (TSI) and spectral solar irradiance (SSI), important for accurate scientific models of climate change and solar variability. TSIS-1 is comprised of two instruments, the Total Irradiance Monitor (TIM), and the Spectral Irradiance Monitor (SIM).

This repository archives Version 5 (V05) of the TSIS-1 SIM Level 3 (L3) data release, and contains SSI in two cadences, 12-hour and 24-hour.

This paragraph is a summary of the version 5 changes and improvements. The degradation corrections have been reprocessed using updated Channel C calibration scans from October 2020, along with an improved degradation model that uses enhanced interpolation techniques. This update has reduced noise in the 400–800 nm and 950–1050 nm ranges. A Level 3 processing issue was fixed to ensure all spectra include the full set of wavelengths, with missing data now correctly flagged rather than omitted. Additionally, when data is back-filled (qualityflag=2), associated uncertainty values are now preserved instead of being set to zero. Temperature fluctuations due to orbital conditions have introduced instrumental effects, particularly during three high-temperature periods in 2019 and 2020. While these effects remain under analysis, their impact has been mitigated by excluding ESR secondary channel data—where the temperature influence was most significant—from the degradation model.

See the attached release notes or the TSIS SIM Data Products Release Notes page (https://lasp.colorado.edu/tsis/data/ssi-data/sim-ssi-release-notes/) for further details, and instructions for obtaining the latest TSIS-1 SIM L3 data release.

Data is archived in ASCII, netCDF, and IDL SAVfile format.