As mentioned above, the colour of a cloud depends on the colour of the light that illuminates it. At sunset or sunrise the colour of sunlight can be yellow to deep red due to the scattering of the blue component of sunlight as the light travels a longer path through the atmosphere.
There are also more subtle ways the colour of a cloud can change such as the colour of the light changing after reflecting off a cloud due to scattering on it's way to the observer, or due to scattering of light by air between the cloud and the observer.
In the first case the blue light will scatter resulting in a white cloud taking on a yellow to red tint. In the second case a white cloud will take on a blue tint due to the blue light scattered by the air between the cloud and the observer.
This is the affect that makes mountains in the distance look blue. Clouds can also look dark or gray. This can be caused a number of different ways. But it is also due to perception by our eyes. A light gray cloud on a bright white background will look much darker than the same cloud on a dark or black background, in which case it might look white and bright.
Excess atmospheric nitrogen dioxide also causes yellow clouds; yellow clouds are more common in urban cities with high air pollution levels. Once suspected to be an optical illusion, green clouds have long been paired with a hail storm or a tornado. It turns out, a greenish cloud is not necessarily a sign of either, despite some interesting folklore.
However, the exact cause of green clouds is still subject to debate today. Many scientists believe that the green tint comes down to the electromagnetic spectrum and the way particles absorb and reflect sunlight. According to one theory, the water droplets in the thunderstorm clouds absorb red light and make the scattered light appear blue. When blue particles or objects are illuminated with red, the net effect is a green shade.
Another theory states that the thunderstorm clouds remove all other wavelengths by acting as a filter, for the green waves to shine. Pink clouds are quite common in some parts of the world, while rare or totally absent in others. They appear mostly sunset and sunrise. In certain areas of the world , especially highly polluted metro cities, the clouds will take a brighter pink to red shade — all thanks to the high concentration of aerosols in the atmosphere.
Aerosols are emitted from automotive vehicles, excess dust, sandstorm, or forest fires. So, deserts, and urban areas with higher traffic are likely to witness pink clouds than any other places. A professional writer, editor, blogger, copywriter, and a member of the International Association of Professional Writers and Editors, New York.
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Asked 6 years, 4 months ago. Active 6 years, 4 months ago. Viewed 2k times. Improve this question. Shivam Vyas Shivam Vyas 31 1 1 silver badge 7 7 bronze badges. Absolutes don't really exist in color perception.
It's rather disquieting when really you start thinking about it! No, you often hear that, but—assuming you mean typical pollution in the lower atmosphere—it's a myth. It's actually the opposite: Large particles in the lower atmosphere tend to mute and muddy the colors because they absorb more light and scatter all the wavelengths more or less equally, so you don't get that dramatic filtering effect.
In areas with a lot of haze, you don't typically see the types of sunsets that are likely to appear on a wall calendar— or in, say, National Geographic. You see bright ones in the fall and winter particularly, especially in the East, because the air along the path of the ray of sunlight tends to be dryer and cleaner.
I grew up in Baltimore, and this is part of why I got interested in weather. I would wonder: Why is the sunset so pretty tonight? And there weren't answers to questions like this in standard weather books, because it's more about physics than forecasting.
Speaking of forecasting, what about the saying: "Red sky at night, sailor's delight; red sky in morning, sailors take warning. Those spectrally pure colors are telling you there's a sizable swath of clear air off to your west that's likely to be over you the next day.
Yeah, you can forecast them to a certain degree. I guess it's a question of who cares—maybe filmmakers or photographers would find that information useful, but most people just want to know if it's going to rain or not. There's often a slanting band of clouds on the back side of the departing weather system, and that can act as a sort of projection screen for the low-sun colors, better than a horizontal band would.
The slant means it captures more of the orange and red light, and if the cloud is thin enough, it will reflect those colors down to you. Also, storms wash a lot of the big particles out of the air. Yes, true sunset occurs a minute or so before you see the sun disappear. What you see is a kind of mirage; the light is getting bent around the horizon by the effect of refraction. Our eyes are sensitive to a very tiny part of the spectrum of the sun's wavelengths, and that's responsible for the way we see our environment.
Other creatures seem able to see the ultraviolet area of the spectrum. We can only see a tiny part of what's going on. So a butterfly or a reindeer , which can perceive ultraviolet light, might be seeing a different, perhaps more colorful sunset than we do? The more you look at things, the more you realize how unique your own experience is as a human on this planet, at this particular place and time. All rights reserved.
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