为什么冰川冰看起来蓝色?- 江南体育网页版- - - - -地球科学堆江南电子竞技平台栈交换 最近30从www.hoelymoley.com 2023 - 04 - 13 - t11:55:01z //www.hoelymoley.com/feeds/question/13240 https://creativecommons.org/licenses/by-sa/4.0/rdf //www.hoelymoley.com/q/13240 29日 为什么冰川冰看起来蓝色? 卡米洛·Rada //www.hoelymoley.com/users/11908 2018 - 01 - 30 - t22:58:29z 2020 - 01 - 03 - t19:23:13z < p >冰川冰中观察到的颜色,冰山和裂隙通常是蓝色的。然而,冰块和工业冰块或白色如果不是完全透明的。< / p > < p >。<强>为什么冰川冰看起来蓝色?

Some examples of what I mean:

Ice blocks enter image description here

Glacier ice enter image description here

PS: As a glaciologist, this is a question I've received a lot, and after Googling for it, the answers I found are not fully satisfactory, so I decided to share mine here in a Q&A format.

 //www.hoelymoley.com/questions/13240/-/13241 # 13241 32 由Camilo Rada回答为什么冰川冰看起来蓝色? 卡米洛·Rada //www.hoelymoley.com/users/11908 2018 - 01 - 30 - t22:58:29z 2019 - 02 - 04 - t01:44:22z < p >简短的回答是:< >强劲,因为冰蓝色的< /强>。< br >现在我们必须解释为什么似乎完全透明的冰块和工业冰块。< / p > < p >这与事实最透明的材料并不是完全透明的,而不是吸收(和/或分散)光击中他们的一部分。当透明度更适合一个特定的颜色(< a href = " https://en.wikipedia.org/wiki/Visible_spectrum " rel = " noreferrer " > < / >)波长,颜色的材料看起来,就像彩色玻璃给色彩如何白光穿过它。< / p > < p >现在重要的事实是,这个“色”效应更强更厚的材料。让我们标准玻璃为例:当透过玻璃似乎完全透明,因为厚度太小,使它的颜色明显。然而,如果你看看玻璃的边缘,它看起来绿色,这表明玻璃的确是绿色的,但通过一段厚时才明显不够。< / p > < p > < a href = " https://i.stack.imgur.com/3vf75.png " rel = " noreferrer " > < img src = " https://i.stack.imgur.com/3vf75.png " alt = "玻璃" > < / > < / p > < p >(图片取自< a href = " http://www.peakglass.ca " rel = " noreferrer " > peakglass.ca < / >) < / p > < p >同样,冰川冰是蓝色的,但这只能欣赏,如果你是块冰足够厚。我们可以看到这种效果在接下来的冰山的照片,在不同粗细的部分显示一个颜色梯度从透明到蓝色。< a href = " https://i.stack.imgur.com/HdHIG.jpg " rel = " noreferrer " > < img src = " https://i.stack.imgur.com/HdHIG.jpg " alt = "冰颜色" > < / > < / p > < p >剩下的问题是:为什么冰川并不总是蓝色?正如我们所知,许多冰山和雪是白色的。< / p > < p >这里的关键是“泡沫”。 The reason is that for each ice/air interface, part of the light gets reflected and only a fraction goes through. Therefore the greater the number of bubbles a piece of ice has, the less light will be able to proceed deeper into the ice. As such, when you view light from more bubbly ice, most of it will have traveled through less ice, and thus have had less distance to obtain the blue tint. I've made this figure to help understanding the idea: light in ice with bubbles diagram

On the left, a piece of ice with very few bubbles allows a longer travel path through the ice, inducing a marked blue tint in the outgoing light. On the right, in contrast, if there are many bubbles the light will go bounce back right away with only a very subtle tint, or no tint at all.

Snow is the extreme of this, because it is mostly air (bubbles), and only some small pieces of ice, that's why it looks so white.

An interesting ramification of this: those deep blue pieces of ice started as snow. But as the snow piles up, the weight of the snow on top compacts it, squeezing air out changing it from snow to firn until you finally reach the density of being a block of ice (with bubbles). In a big glacier, hundreds or thousands of meters of ice can exert such a pressure that the bubble spaces get compacted smaller and smaller until they disappear and the air is dissolved into the ice itself.
Therefore this means that the more blue (and bubble-less) a piece of ice is, the more it has come from deeper within the glacier... meaning it also has traveled from further up in the glacier basin and it is, therefore, older. So, now you can identify deep, old ice just by its color.

To give a more familiar example of how adding bubbles can turn something transparent with a tint into something white, take the case of egg whites, which are transparent with a yellowish tint. But as you whip it, adding in bubbles, it begins to turn into meringue which is perfectly white. making meringue

However, there is a trick that can even make the blue color of seemingly-white snow noticeable. If you let a ray of light bounce on it many times, each time it will travel through a little bit of ice, getting a bit of blue tint each time, and after enough bounces it will look unquestionably blue. That's what you see when looking at the entrance of a snow cave or a crevasse in a glacier. The light that comes from deeper in the cave has bounced many more times around the walls and becomes bluer: enter image description here (Picture taken from outdoorlifenorway.com)
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