In weather reports what does satellite brightness mean?

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Offline thedoc

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Judi Heitz  asked the Naked Scientists:
   Hello all of you professional science nerds!  
Here's the question:
I often check the weather on weatherunderground  https://www.wunderground.com/  and they have a section showing a world map with today's weather events.  They often have icons that show fires, earthquakes, etc.  The fires say a fire in such and such a place found by satellite and with a brightness of 412.
Can you explain what the brightness scale works and how they determine a world fire?  I don't know if 412 is very bright, or if it's just bright compared the the area next to it... ?
Maybe you can do a show on  how satellites are used to identify and predict weather...
Thanks so much

Thank you for your work.  You are truly making a difference. I've listened for years.

Judi Heitz







 
What do you think?
« Last Edit: 14/03/2016 14:50:02 by _system »

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Offline evan_au

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Re: In weather reports what does satellite brightness mean?
« Reply #1 on: 14/03/2016 20:03:02 »
The fires are shown here - click to see which satellite observed it: http://www.wunderground.com/fire/

These Earth observation satellites often have infra-red cameras at multiple wavelengths, which can spot the difference between sunlight reflected from foliage, and wildfires. It is even easier to spot the differences at night.

I see that one of these fires was spotted by GOES-WEST: http://en.wikipedia.org/wiki/Geostationary_Operational_Environmental_Satellite