Solar Variability and Total Solar Irradiance (TSI)

  • Released Thursday, February 19, 2009

Analyzing the Sun and its effects on climate is complicated by the fact that the amount of radiation arriving from the Sun is not constant. It varies from the average value of the total solar irradiance (TSI)—1,361 W/m2—on a daily basis. Variations in TSI are due to a balance between decreases caused by sunspots and increases caused by faculae, which are the bright areas that surround sunspots. The Sun's energy output varies with time, and Glory's TIM instrument will help measure those fluctuations by continued monitoring of TSI. Data from TIM will extend the long-term climate record, which has been uninterrupted since 1978 and provides the best estimate available of solar inputs to climate. This short movie displays the Sun rotating and the corresponding total solar irradiance.

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Please give credit for this item to:
Laboratory for Atmospheric and Space Physics.

Release date

This page was originally published on Thursday, February 19, 2009.
This page was last updated on Wednesday, May 3, 2023 at 1:54 PM EDT.


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