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Icelights: answers to your burning questions around ice and climate

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What"s hot in the news about climate and sea ice and also what are researchers talking about now? review more...


What is the Cryosphere?

When researchers talk around the cryosphere, they mean the places on planet where water is in its solid form, frozen into ice or snow. Read more ...


Snow is an build-up of packed ice crystals, and the problem of the snowpack identify a selection of qualities, such as color, temperature, and water equivalent. Together weather conditions change, the snowpack can change as well, and this influence the features of the snow.

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Snow most frequently appears white, yet deep snow have the right to act together a filter, absorbing more of one color and less that another. Deep snow tends to absorb red light, mirroring the blue tints regularly seen in snow.—Credit: Paul WatsonThe colors of snow

Generally, snow and ice existing us through a uniformly white appearance. This is since visible irradiate is white. Most every one of the visible light striking the eye or ice surface ar is reflected back without any particular preference for a solitary color. Most organic materials absorb part sunlight, which gives them your color. Clean snow, however, reflects many of the sunlight, developing a white appearance. Exactly how much sunlight the snowpack mirrors to the setting is characterized as snow"s albedo.

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The watermelon eye at the edge of this glacier in Montana is led to by algae living in the snow.—Credit: Carol Neuhoff

However, snow may additionally appear blue. Together light waves travel right into the snow or ice, the ice cream grains scatter a big amount the light. If light travels over any distance, it have to survive countless such scattering events. That is, it need to keep scattering and not it is in absorbed. The observer look at the light coming ago from the near surface layers after it has actually been scattered or bounced off other snow grains just a few times and it still shows up white. This absorb is preferential: an ext red light is absorbed than blue. The difference in absorb is small, yet is sufficient that end a considerable distance, say a meter (3.3 feet) or more, photons arising from the snow layer often tend to be comprised of an ext blue light 보다 red light. Because that instance, if you were to bag a hole in the snow and look down right into the hole, you might see a bluish color. In every case, the blue light is the product that a fairly long travel route through the snow or ice. Think the the ice or eye layer as a filter. If that is just a centimeter (0.39 inches) thick, every the light makes it through, however if it is about one meter (3.3 feet) thick, greatly blue light makes it through.

Particles or organisms in ~ the snowpack might also impact the color of the snow. Watermelon snow, because that instance, appears red or pink. This coloration is resulted in by a kind of cryophilic, or cold-loving, fresh-water birds that save on computer a bright red pigment. Watermelon eye is most usual during the summertime in high alpine areas as well as along coastal polar regions. Return this snow might look candy-colored, it is not wise come eat it. Blood Falls, in Antarctica"s Taylor Glacier, also has red snow, but for a different reason. There, the deep red shade is led to by saltwater leaking from an old reservoir under the glacier. This water is well-off in a type of iron the oxidizes once it come into call with the atmosphere, producing a bright red waterfall.

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Iron-rich water leaking indigenous Antarctica"s Taylor Glacier produces the deep red color of Blood Falls.—Credit: Peter Rejcek, U.S. Antarctic Program, nationwide Science Foundation

Dark-colored corpuscle such as dust and also soot can change snow"s figure and, due to the fact that they absorb much more sunlight, hasten snow"s retreat. Researches in the southwestern Colorado mountain Juan hills have presented that a great of dust in ~ the surface of a snowpack have the right to shorten the duration of snow cover everywhere from 21 to 51 days. In contrast, an air temperature rise of 2 come 4 levels Celsius (4 come 7 degrees Fahrenheit) would certainly shorten eye cover term by just 5 to 18 days. Dust great can become buried in the snowpack as new storms add clean snow on top, yet these dust layers will certainly reemerge together the top layers melt away.

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A coating the dust dims snow"s appearance and hastens its melt.—Credit: Jeff Deems, ugandan-news.comSnow and also sound

The characteristics and age of snow can influence how sound waves travel, dampening them in some cases, or boosting them in others. Because that instance, people often notification how sound alters after a fresh snowfall. Once the ground has a thick layer of fresh, fluffy snow, sound waves room readily soaked up at the eye surface, dampening sound. However, time and weather conditions may change the snow surface. If the surface ar melts and refreezes, the eye becomes smooth and hard. Then the surface ar will assist reflect sound waves. Sounds might seem clearer and also travel aside from that under this circumstances.

Snow may also crunch and also creak. A layer of snow is comprised of numerous tiny ice cream grains surrounding by air and when you action on it, girlfriend compress the grains. Together the eye compresses, the ice cream grains rub against each other. This creates friction or resistance; the reduced the temperature, the higher the friction between the grains of ice. The sudden squashing the the eye at lower temperatures produces the acquainted creaking or crunching sound. At greater temperatures, closer come melting, this friction is reduced to the suggest where the slide of the grains versus each other produces little or no noise. It is challenging to say in ~ what temperature the eye starts come crunch, however the chillier the snow, the louder the crunch.

Snow and insulation

Snow is such a an excellent insulator that some pets dig snow caves in which to hibernate through the winter. New snow is created of a high percentage of air trapped among the built up snow crystals. Due to the fact that the air can barely move, warmth transfer is greatly reduced. Fresh, uncompacted snow typically is 90 come 95 percent trapped air. Many animals take advantage of snow"s insulating qualities, and also burrow into the snow to hibernate v the winter.

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Snow campers occasionally dig snow caves to sleep in, taking benefit of snow"s insulating properties. Although eye is cold, the wait temperature within a snow cavern will remain greater than the outside air temperature, which deserve to drop substantially at night.—Credit: El Capitan, FlickrSnow depth and also temperature

The snow surface temperature is controlled by the waiting temperature above. The cooler the waiting above, the cooler the snow layers near the surface ar will be, especially within the top 30 come 45 centimeters (12 come 18 inches). Snow close to the floor in depths snowpack is warmer because it is close to the warmth ground. The soil is fairly warm due to the fact that the warm stored in the ground over the summer is sluggish to dissipate. In addition, snow is a good insulator, similar to the insulation in the ceiling the a house, and thus slows the circulation of warmth from the warm ground come the cold waiting above.

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Snow water equivalent

Snow is created of frozen water crystals, but due to the fact that there is so lot air surrounding each the those small crystals in the snowpack, many of the total volume of a eye layer is consisted of of air. We describe the snow water tantamount of snow as the thickness that water the would an outcome from melting a provided layer of snow. An often-repeated assumption claims a ten-to-one proportion of snow to water, but that is not always accurate. The water indistinguishable of eye is more variable than most human being realize. For instance, 25 centimeters (10 inches) of new snow can contain as tiny as 0.25 centimeters (0.10 inches) of water and also as much as 10 centimeters (4 inches) the water, depending on crystal structure, wind speed, temperature, and also other factors. The bulk of brand-new snowfall in the unified States consists of a water-to-snow proportion of between 0.04 (4 percent) and 0.10 (10 percent), relying on the meteorological conditions connected with the snowfall.