TSIS: The Total and Spectral Solar Irradiance Sensor

The Total and Spectral Solar Irradiance (TSIS) will make key measurements of solar forcing of the climate system as part of the NOAA-NASA Joint Polar Satellite System (JPSS). Total solar irradiance (TSI) is required for the establishing the total energy input to Earth, the primary variable for understanding the exchange of energy between Earth and space. Solar spectral irradiance (SSI) is necessary to understand how the climate responds to the Sun's changes. Both variables are required measurements of TSIS, mandated in the original NPOESS Environmental Data Records, and now carried on in the JPSS Climate Data Records.

The two TSIS instruments are the Total Irradiance Monitor (TIM), and the Spectral Irradiance Monitor (SIM), heritage instruments to those currently flying on the NASA Solar Irradiance and Climate Experiment (SORCE). TIM and SIM were selected as part of the TSIS because of their unprecedented measurement accuracy and stability, and because both measurements are essential to constraining the energy input to the climate system and interpreting the response of climate to external forcing.

This paper will describe those attributes of TSIS which uniquely define its capability to continue the 34-year record of TSI and to extend the new 9-year record of SSI. We will discuss the role of solar irradiance and TSIS within the NOAA Climate Data Record Program, including the maturity of transition from research-to-operations.