Solar irradiance is a vital source of energy input for the Earth’s climate system and its variability has the potential to mitigate or exacerbate a human-created climate. Maintaining an unbroken record of Total Solar Irradiance (TSI) is critical in resolving ongoing debates regarding the potential role of solar variability in influencing Earth’s climate. Space-borne instruments have acquired TSI data since 1978. Currently, the best calibrated and lowest noise source of TSI measurements is the Total Irradiance Monitor (TIM) onboard NASA’s Solar Radiation and Climate Experiment (SORCE). These TIM-era data are of higher quality than the older data in the full record. Thus, the TSI climate data record (CDR) has two components. There is the shorter, but more accurate record of the TIM era and the full (33+ year) space-based TSI measurement record. Both are important and require preservation.

Review of NOAA Working Group Report on Maintaining the Continuation of Long-Term Satellite Total Irradiance Observations evaluates NOAA’s plan for mitigating the loss of total solar irradiance measurements from space, given the likelihood of losing this capacity from instruments currently on the SORCE satellite in coming years and the short term/experimental nature of the currently identified method of filling the data gap. This report evaluates NOAA’s plan for mitigating the gap in total solar irradiance data.