5835 20220920104654.0 10.3390/rs14051072 DOI SCART-2022-0081 Dewitte, Steven Centennial Total Solar Irradiance Variation 2022 Total Solar Irradiance (TSI) quantifies the solar energy received by the Earth and therefore is of direct relevance for a possible solar influence on climate change on Earth. We analyse the TSI space measurements from 1991 to 2021, and we derive a regression model that reproduces the measured daily TSI variations with a Root Mean Square Error (RMSE) of 0.17 W/m2. The daily TSI regression model uses the MgII core to wing ratio as a facular brightening proxy and the Photometric Sunspot Index (PSI) as a measure of sunspot darkening. We reconstruct the annual mean TSI backwards to 1700 based on the Sunspot Number (SN), calibrated on the space measurements with an RMSE of 0.086 W/m2. The analysis of the 11 year running mean TSI reconstruction confirms the existence of a 105 year Gleissberg cycle. The TSI level of the current grand minimum is only about 0.15 W/m2 higher than the TSI level of the grand minimum in the beginning of the 18th century. NO total solar irradiance sunspot number Cornelis, Jan Meftah, Mustapha Remote Sensing 14 2022 5 elodie.brahy@ksb-orb.be https://www.mdpi.com/2072-4292/14/5/1072 published in REFERD