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Water has lowest EM absorption in the blue part of light spectrum and increases rapidly towards both UV and red parts of spectrum. As a result in visible light water is blue. Same goes for the ice as it has very similar absorption spectrum. While there is a lot of white in the picture, all of it is a thin snow cover on top of blue ice. Once the snow ...


15

"Transparent" is not the same as "white" : white bodies reflect most of the light while transparent bodies let the light though. Once the light enters into water, it may need to travel a long way before it has a chance to go out, and that long travel path provides more opportunities for absorption. Water absorbs light by itself much more than snow, but ...


12

I had a very similar question in a job interview! The only difference is that it was an image from SEVIRI on Meteosat. The imager on HIMAWARI is called the Advanced Himawari Imager (AHI). The AHI IR1 channel is actually channel 13 with a central wavelength of 10.4 µm, which is in the window region (apparently it's called IR1 in reference to an older ...


11

It is likely because there is already a conversion from the raw data to the grayscale image posted on the CWB website. From this online course (emphasis mine): [...] using the mathematics behind the laws of radiation, computers can convert the amount of infrared radiation received by the satellite to a temperature (formally called a "brightness ...


2

The yearly average Top Of Atmosphere (TOA) Outgoing Longwave Radiation (OLR) is around 145–345 W/m², as measured by the AIRS instrument: Source: Wikimedia Commons contributors, "File:AIRS OLR.png," Wikimedia Commons, the free media repository. Now, this is an average that includes both day and night. How much does it vary? This depends on the location. ...


1

Water (solid or liquid) has some absorbtion. It is rather low for pure water for visible or near-visible light and that's why water it is considered transparent. But only to an extent - few meters of water look blue and few hundred meters look black, esp. if you are UNDER those few hundred meters. Then we have snow. Snow has an abundance of optical ...


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