Why Was Yesterday's Sunlight Brighter Than This Morning?

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Discussion Overview

The discussion centers around the perceived difference in brightness of sunlight between two mornings, specifically comparing conditions on July 12 and July 13, 2016, in the San Francisco Bay Area. Participants explore potential explanations for this phenomenon, considering both subjective observations and atmospheric conditions.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes a subjective perception of brightness on July 12 compared to July 13 without using a light meter for measurement.
  • Another participant questions the reliability of visual perception, suggesting that environmental factors, such as transitioning from a darker area, could influence the observation.
  • A participant mentions a change in color temperature around 11:00 am to 11:50 am PDT, indicating a potential shift in lighting conditions.
  • It is proposed that variations in atmospheric conditions, such as the presence of aerosols, smog, or fog, could account for differences in perceived brightness.
  • A reference to weather data indicates that the weather was clear on July 12 and partly cloudy on July 13, which may have contributed to the observed differences.
  • A participant expresses intent to use a spectrometry kit to measure light, although they acknowledge potential limitations in sensitivity.

Areas of Agreement / Disagreement

Participants express differing views on the reliability of personal observations versus measurable data. There is no consensus on the cause of the perceived brightness difference, and multiple factors are suggested as potential explanations.

Contextual Notes

Limitations include the lack of quantitative measurements and reliance on subjective visual perception, which may not accurately reflect actual brightness levels. The discussion also highlights the influence of atmospheric conditions, which remain unresolved.

Who May Find This Useful

This discussion may be of interest to individuals exploring atmospheric science, perception studies, or those curious about the effects of weather on light conditions.

Alan Arqueza
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Yesterday morning the lighting from the sunlight made everything brighter until 11:50am Pacific Daylight time. I am in the San Francisco Bay Area in Northern California. Can you explain why sunlight on 13 July 2016 appears to be 'brighter' than this morning?
 
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Alan Arqueza said:
Yesterday morning the lighting from the sunlight made everything brighter until 11:50am Pacific Daylight time. I am in the San Francisco Bay Area in Northern California. Can you explain why sunlight on 13 July 2016 appears to be 'brighter' than this morning?

This is vague. Did you actually measure this brightness, or are you just relying on what you see with your eyes? The latter is not terribly reliable, because it depends many circumstances (i.e. did you just walk out of a darker area when you went outside?).

Zz.
 
I was looking out the window this morning and noticed how the brightness was not the same compared to yesterday. Yesterday morning I was looking out the window from the same room. I did not use a light meter to measure the lighting.
 
The color temperature changed around 11:00 am - 11:50 am Pacific Daylight Time. I noticed the color temperature or hue changed around 11:50am PDT. I should have written the time.
 
If there was a real difference and not just your eye's unreliable perception, it could probably be described by the varying amounts of aerosols in the atmosphere smog, fog, etc etcrelying just on your eyes like that would be very unreliable
 
According to weatherunderground.com, at 11 this morning it was partly cloudy and 11 yesterday morning it was clear.
 
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I will use the Desktop Spectrometry Kit 3.0 from Public Lab. This spectrometry kit may not be sensitive enough.
 
Well, interesting
 

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