<p>Phys.org's <a href="https://phys.org/news/2020-03-solar-energy-tracker-powers-years.html" rel="nofollow noreferrer">Solar energy tracker powers down after 17 years</a> says:</p>
<blockquote>
<p>&quot;<strong>The big surprise with TSI was that the amount of irradiance it measured was 4.6 watts per square meter less than what was expected</strong>,&quot; said Tom Woods, SORCE's principal investigator and senior research associate at the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP) in Boulder, Colorado. &quot;That started a whole scientific discussion and the development of a new calibration laboratory for TSI instruments. <strong>It turned out that the TIM was correct, and all the past irradiance measurements were erroneously high.</strong>&quot;</p>
<p>&quot;It's not often in climate studies that you make a quantum leap in measurement capability, but the tenfold improvement in accuracy by the SORCE / TIM was exactly that,&quot; said Greg Kopp, TIM instrument scientist for SORCE and TSIS at LASP.</p>
</blockquote>
<p><strong>Question:</strong> What was it about either the past measurements or their analysis or calibration that made their measurements of the Sun's output about 0.3% high? What TSI's improvement primarily instrumental, or due to better calibration?</p>

<the-sun><observational-astronomy><solar-system>
Why were solar constant measurements before TSIS-1 all about 0.3% high?
uhoh
# Why were solar constant measurements before TSIS-1 all about 0.3% high?

(Asked by: username_0 on 2020-03-21)

Phys.org's [Solar energy tracker powers down after 17 years](https://phys.org/news/2020-03-solar-energy-tracker-powers-years.html) says:

> "**The big surprise with TSI was that the amount of irradiance it measured was 4.6 watts per square meter less than what was expected**," said Tom Woods, SORCE's principal investigator and senior research associate at the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP) in Boulder, Colorado. "That started a whole scientific discussion and the development of a new calibration laboratory for TSI instruments. **It turned out that the TIM was correct, and all the past irradiance measurements were erroneously high.**"
>
> "It's not often in climate studies that you make a quantum leap in measurement capability, but the tenfold improvement in accuracy by the SORCE / TIM was exactly that," said Greg Kopp, TIM instrument scientist for SORCE and TSIS at LASP.

**Question:** What was it about either the past measurements or their analysis or calibration that made their measurements of the Sun's output about 0.3% high? What TSI's improvement primarily instrumental, or due to better calibration?

**Tags:** the-sun, observational-astronomy, solar-system

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## 0 answers

