The TSIS TIM is a heritage instrument of currently flying SORCE TIM. The TIM will measure the total solar irradiance (TSI), the spatially and spectrally integrated solar radiation incident at the top of the Earth’s atmosphere.Using electrical substitution radiometers (ESRs) and taking advantage of new materials and modern electronics, the TIM measures TSI to an estimated absolute accuracy of 100 ppm (0.01%). Relative changes in solar irradiance will be measured to less than 10 ppm/yr (0.001%/yr), allowing determination of possible long-term variations in the Sun’s output.TSIS TIM is going to continue the 38-year record of TSI as an Environmental Data Record into the future.

More information on SORCE TIM here

More information on TSI here