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TCTE

Total Solar Irradiance Calibration Transfer Experiment

Monitored incoming solar energy to study the causes of climate change

The Total Solar Irradiance Calibration Transfer Experiment (TCTE) operated from November 2013 until June 2019, and monitored incoming solar energy to help scientists understand the causes of climate change on our planet. Incident sunlight—the sunlight that falls directly on a surface—is the primary energy source that drives Earth’s climate. TCTE measured total solar irradiance (TSI), or the total light coming from the Sun at all wavelengths, in order to monitor changes in the incident sunlight at the top of Earth’s atmosphere. The mission assisted in maintaining measurement continuity of the four-decade-long TSI climate data record following the loss of the NASA Glory mission in 2011.

Mission Class:

Larger Missions

Mission Status:

Past

LASP Roles:

Research, Instruments, Lead Institute

Science Target:

Earth's Atmosphere

Mission Focus:

Climate, Solar Irradiance

Primary Mission Site:

https://lasp.colorado.edu/tcte/

Launch Date: November 19, 2013
Decommission Date: June 2019

Lead Institution: LASP

Lead Funding Agency: NASA

Partners: U.S. Air Force

The TCTE TIM monitored the incident sunlight to the Earth’s atmosphere using an ambient temperature active cavity radiometer. Using electrical substitution radiometers (ESRs) and taking advantage of new materials and modern electronics, TCTE measured TSI to an estimated absolute accuracy of 350 ppm, or 0.035%. TCTE measured relative changes in solar irradiance to less than 10 ppm/yr (0.001%/yr), which assisted in the determination of possible long-term variations in the Sun’s output.