Total Irradiance Monitor (TIM): New Results for TSI

Greg Kopp [greg.kopp@lasp.colorado.edu], Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder.

The Total Irradiance Monitor (TIM) continues to perform excellently, producing daily total solar irradiance (TSI) measurements. The measured TIM TSI remains at about 1361 W/m2, or 4-5 W/m2 lower than that measured by other current TSI instruments. TSI instrument accuracies were the topic of a recent NIST and NASA workshop in which TIM personnel participated. The TIM shows very little (~50 ppm/yr with corrections known to better than 10 ppm/yr) optical degradation from solar exposure, and the electronics show no signs of change since launch. This level of long-term stability may eventually facilitate the direct determination of a secular change in TSI.

TIM TSI measurements from 1 March 2003 to the present are available. Daily data updates lag data acquisition by roughly 7 days, and we are evaluating making processed data available within a day of telemetry of raw data for quicker comparisons with other solar activity indicators.