Tag Archives: snow

Snowfall in the Alps is full of plastics particles

New research from the Swiss Federal Laboratories For Materials Science And Technology (EMPA), Utrecht University, and the Austrian Central Institute for Meteorology and Geophysics showcase the scale and huge range of pollution carried through the atmosphere.

The research site at Sonnblick. Image credits ZAMG / Christian Schober via Flickr.

The findings suggest that around 3,000 tons of nanoplastic particles are deposited in Switzerland every year, including the most remote Alpine regions. Most are produced in cities around the country, but others are particles from the ocean that get introduced into the atmosphere by waves. Some of these travel as far as 2000 kilometers through the air before settling, the team explains, originating from the Atlantic.

Such results build on a previous body of research showing that plastic pollution has become ubiquitous on Earth, with nano- and microplastics, in particular, being pervasive on the planet.

Plastic snow

Although we’re confident that the Earth has a plastic problem, judging by the overall data we have so far, the details of how nanoplastics travel through the air are still poorly understood. The current study gives us the most accurate record of plastic pollution in the air to date, according to the authors.

For the study, the researchers developed a novel chemical method that uses a mass spectrometer to measure the plastic contamination levels of different samples. These samples were obtained from a small area on the Hoher Sonnenblick mountain in the Hohe Tauern National Park, Austria, at an altitude of around 3100 meters from sea level. This area was selected as an observatory of the Central Institute for Meteorology and Geodynamics and has been in operation here since 1886.

The samples were collected on a daily basis, in all types of weather, at 8 AM. They consisted of samples of the top layer of snow, which were harvested and processed taking extreme care not to contaminate them with nanoplastics from the air or the researchers’ clothes. According to their measurements, about 43 trillion miniature plastic particles land in Switzerland every year — equivalent to around 3,000 tons.

In the lab, the team measured nanoplastic content in each sample and then analyzed these particles to try and determine their origin. Wind and weather data from all over Europe were also used in order to help determine the particles’ origins. Most of the particles were likely produced and released into the atmosphere in dense urban areas. Roughly one-third of the particles found in the samples came from within 200 kilometers. However, around 10% of the total (judging from their level of degradation and other characteristics) were blown to the mountain from over 2000 kilometers away, from the Atlantic; these particles were likely formed in the ocean from larger debris and introduced into the atmosphere by the spray of waves.

Plastic nanoparticles are produced by weathering and mechanical abrasion from larger pieces of plastic. These are light enough to be comparable to a gas in behavior. Their effect on human health is not yet known, but we do know that they end up deep into our lungs, where they could enter our bloodstream. What they do there, however, is still a mystery.

The current study doesn’t help us understand their effects any better, but it does put the scale of nanoplastic pollution into perspective. These estimates are very high compared to other studies, and more research is needed to verify them — but for now, they paint a very concerning picture.

The paper “Nanoplastics transport to the remote, high-altitude Alps” has been published in the journal Environmental Pollution.

Is the snow turning red in Antarctica? Well, not exactly

Are my eyes playing tricks or did the snow in Antarctica turned red? That’s what many people recently asked after seeing viral photos from a Ukrainian based, fully covered by red or watermelon snow.

Image credits Андрей Zotov (Andrey Zotov) / The National Antarctic Scientific Center of Ukraine via Facebook.

But there’s a logical explanation behind the phenomenon. The color is due to the flowering of thousands of unicellular algae called Chlamydomonas nivalis, which contain red carotene (astaxanthin) to protect against ultraviolet radiation.

The substance “acts as a sunscreen, protecting the algae from the dreaded ultraviolet radiation, but allowing the passage of other wavelengths necessary to perform photosynthesis,” said the Spanish physicist Mar Gomez on a Twitter thread.

The viral photos were captured by marine ecologist Andrey Zotov from the National Academy of Sciences of Ukraine while he was doing research in the area. He and his colleagues identified the green algae, common in icy and snow regions, with a microscope.

Zotov explained that the green algae sleep during the winter and then wakes up later in the year thanks to the higher temperatures and the sunlight. The algae use the sunlight and the meltwater to bloom, which is the phenomenon seen in the photos.

But this is not exclusive to the green algae, as there are more than 350 different types that can survive extreme temperatures.

The green algae have a two tail-like structure that allows them to swim. When they mature, they lose that mobility but develop features to survive the extreme temperatures, including an insulating cell wall and a layer of red carotenoids, changing their appearance from green to orange to finally red.

At the same time, the carotenoids help the algae to absorb warmth, creating more meltwater for them to thrive. While this is helpful for the algae, it’s not so much for the planet, as the algae bloom has been found to contribute to climate change.

In 2016, a study concluded the snow algal blooms decreases the amount of light reflected from the snow by 13% in one melt season in the Arctic. At the same time, in 2017, researchers argued microbial communities, including the algae, contributed to more than a sixth of the snowmelt in the locations they were present.

Temperature records continue to be broken in Antarctica, one of the regions in the world most affected by climate change, causing the rapid melting of snow and ice. Since the 1950s, the temperature in Antarctica has risen by more than 0.05 °C (0.09 °F) per decade.

Between 1979 and 2017, Antarctica has experienced a sixfold increase in yearly ice mass loss — and this rate doesn’t seem to be slowing down. During this period, global sea levels rose by almost 13 millimeters (half an inch), according to a recent study.

In the Earth’s core, it’s snowing iron

Christmas is just around the corner, and with it, inevitably, come songs of “let it snow”. This particular carol is also relevant at the Earth’s core, a new study shows. According to the findings, iron snow blankets our planet’s internal core year-round.

Image credits Hendrik Kueck / Flickr.

Extreme pressure and heat don’t rule out snow, it seems, but it does make it more metal. Particles of iron that form in the Earth’s outer core ‘snow down’ on top of the inner core, a new study reports, and pile up in layers up to 200 miles thick.

The Earth’s inner core is hot, under immense pressure and snow-capped, according to new research that could help scientists better understand forces that affect the entire planet.

The snow is made of tiny particles of iron — much heavier than any snowflake on Earth’s surface — that fall from the molten outer core and pile on top of the inner core, creating piles up to 200 miles thick that cover the inner core. The findings could help explain anomalies seen in geophysical systems and improve our understanding of the processes taking place in the heart of our planet.

Inside knowledge

“The Earth’s metallic core works like a magma chamber that we know better of in the crust,” said Jung-Fu Lin, a professor in the Jackson School of Geosciences at The University of Texas at Austin and a co-author of the study.

Since the Earth’s interior is a tad inaccessible to us, researchers use seismic waves to investigate its structure and behavior. We know how seismic waves act in different contexts from experiments done on the surface, so we can estimate how they will behave inside the planet based on our current models of Earth’s structure. Whenever we see something that doesn’t go according to our predictions, it’s a good sign that our model was wrong — and we update it to fit the results.

One area where our predictions didn’t match results is at the boundary between the outer and inner core. Seismic waves move more slowly through this area than we expected, and move faster than we thought they would through the eastern hemisphere of the topmost inner core.

The study proposes that the layers of ‘iron snow’ that form on the core can explain the results. The existence of this slurry-like layer has been suggested since the early 1960s, but the data needed to support this view proved elusive.

In the study, Zhang and his team explain that crystallization was possible in this layer of the Earth and that about 15% of the lowermost outer core could be made up of iron-based crystals. It’s these crystals that fall down and settle onto the liquid inner core like a blanket of snow. This build-up is the cause of the anomalous seismic readings in the area, they add.

“It’s sort of a bizarre thing to think about,” said Nick Dygert, an assistant professor at the University of Tennessee who co-authored the study. “You have crystals within the outer core snowing down onto the inner core over a distance of several hundred kilometers.”

Seismic waves move faster through denser material — and the slurry-like coating of iron crystals slows them down. Because there is a variation in the thickness of these deposits around the inner core, with the eastern hemisphere showing thinner packs, seismic wave speed isn’t constant throughout the boundary.

“The inner-core boundary is not a simple and smooth surface, which may affect the thermal conduction and the convections of the core,” Zhang said.

The Earth’s core is the lynchpin in phenomena that affect the planet as a whole, from supplying the heat that drives plate tectonics to the generation of its magnetic field. Better understanding its structure and properties can help us make better sense of the processes it partakes in — and of other planets as well.

The paper “Fe Alloy Slurry and a Compacting Cumulate Pile Across Earth’s Inner‐Core Boundary” has been published in the Journal of Geophysical Research: Solid Earth.

That lovely Christmas snow? It probably has microplastics in it

From the waters of Antarctica to the food we eat, microplastics are all over the place, with scientists still trying to understand the consequences they have for the environment and our health.

Microplastics are everywhere, and they’re probably also in the pristine white snow.

Credit Wikipedia Commons

Any piece of plastic under the size of five millimeters (0.2 inches) is considered a microplastic. Microplastics can be produced at that size, or come from the degradation of larger pieces.

They enter ecosystems from different sources such as cosmetics and clothing and even eaten by all of us without being aware of it.

Researchers first believed microplastics were transported mainly by water, but that turned out to not be the case.

A 2017 study showed microplastics are even in our drinking water, with the US having the highest contamination rate. But now it has become clear that they can also be transported by wind, ending up in the snow.

The first studies detailing wind transport appeared earlier this year. In April, a group of researchers from France and Scotland discovered microplastic in the Pyrenees, which had been blown in on the wind from Barcelona. Just a few months later, researchers found them in the snow of the Swiss Alps and the Arctic, likely transported by the wind.

On what was the most recent study, researchers from the Desert Research Institute of Reno also found microplastics in the snow of the Sierra Nevadas mountains in California.

This means there’s plenty of microplastics in the air — enough to be considered a type of air pollution — and yes, that also means there’s probably microplastics in snow.

The researchers that worked on the snow of the Alps and the Artic found an average of 1.760 microplastic particles per liter of snow that had fallen on icebergs between Greenland and Norway. The number was much higher in the European Alps locations, with 24.600 particles per liter on average.

The role of microplastics in the snow hasn’t received much attention from researchers so far. That’s why, for example, Columbia University has created a citizen science project called PlastiX-Snow Citizen Science to collect data on this. They hope to get samples of snow meltwater from people all over the US.

“Despite its importance, little is known about microplastic transport and deposition, especially by snow particles, and most people are not aware of the extent of the problem,” an abstract of their plan reads. “The project aims to fill these research and informational gaps using crowd-sourcing to achieve scientific research outputs”

Why is snow white?

Every time it snows, the world turns white, even for the briefest of moments. Today we’re taking a look at why that is.

Snow street.

Image via Pixabay.

You likely hear the song “White Christmas” played every time the winter holidays swing around. It goes to show just how deep cultural associations between snow and its color — that striking, pure, sparkling white — run. If you think about it, however, something doesn’t add up. Snow is basically made up of tiny crystals of water (ice) caked one on top of the other. Water isn’t white; nor is ice, for that matter.

Logic dictates that there must be another element coming into the mix to make snow, well, snow-white. There is. To whet your appetite, it’s basically the same process that makes polar bears appear white. So let’s see what it is.

Color me surprised

To get a clearer picture of why snow appears white, we need to take a look at what generates color in the first place.

Our eyes are basically sensors designed to pick up on a particular spectrum of electromagnetic radiation — which, surprise, surprise, we call the ‘visible light’ spectrum. We perceive different wavelengths or intervals of this spectrum as different colors: ‘wider’ waves look red to us, while ‘narrower’ waves appear to be blue.

Light is pretty much like any other type of radiation. When it hits an object, it can pass through, interact with it, or be reflected completely. Objects take on different colors because their individual building blocks (atoms or molecules) vibrate in response to different frequencies of energy (such as that carried by light). They absorb a particular band of energy to sustain this vibration — which transforms it to heat. The light frequencies which don’t get absorbed can keep going through this material (which makes it transparent or translucent) or get reflected (making the material opaque).

What you see as ‘color’ is the blend of all energy intervals or bands from the visible spectrum that a material doesn’t absorb. Think of white light as a sum of all the colors canceling each other out. To get a particular shade, then, you need to do one of two things. You can subtract its opposite, which we call its ‘complementary’ (here’s a handy color wheel), from the mix, leaving that particular color ‘uncanceled’. Alternatively, you can absorb all other wavelengths and reflect only the color you want.

As an example, leaves appear to be a fresh green because chlorophyll absorbs the wavelengths corresponding to red and blue. Their complementary colors are green and orange/yellow. Leaves absorb only a fraction of the green wavelengths, and what’s reflected creates their color. It’s particularly interesting to note that sunlight is heavy in the green-wavelengths of light. Plants want red and blue light because they’re the less energetic parts of solar radiation. Going for the green spectrum would actually radiation-fry the leaves’ biochemical gears.

Don’t judge a snow by its color

If you put a chunk of ice next to a handful of snow, it’s pretty easy to tell that their colors do not match. One looks basically like solid water while the other is all glimmery, white, and definitely not transparent. So what gives?

Well, first off, caution to the wise: ice isn’t transparent — it’s translucent. Some of the atoms in the ice molecule are close enough to alter lightwaves as they come into contact. Think of it like the light having to squeeze between these atoms as it passes through ice. It doesn’t bother the light very much, but it does ‘bend’ its trajectory a little. Put your finger in a glass of water, and the submerged part will look skewed compared to the rest of your hand; it’s the same process at work.

Shape and size also make an appearance here. Snow is made up of many tiny ice crystals stacked together. When light encounters snow, it goes through the first layer of crystals and gets bent a little. From here, it passes to a new crystal, and the process repeats. Kind of like a disco ball, the snow keeps refracting light until it’s bent right out the pile. Since ice is translucent (doesn’t absorb any wavelength of light), the color of this light isn’t altered, so it’s still white when it exits the pile of snow to hit your retina.

Powder snow.

Matte but glittery.
Image via Pixabay.

The small size of ice crystals in snow also gives it that ‘matte but glittery’ look. Smooth objects reflect light specularly, or like a mirror. Rough surfaces scatter the light they reflect instead, which is why we can perceive texture from looking at an object. The crystals in snow are smooth, so each reflects light specularly. From the right angles, you can see this as tiny, bright reflections on the ice. When clumped up together, however, the crystals scatter light overall. Because the way light falls on it helps create the color, snow can take shades of blue, purple, or even pink in certain circumstances — when it’s in shadow, for example.

As for the polar bears, they’re not really white. Their fur is actually pretty dark in color. Polar bears’ coats are made of two layers of hairs, one short and thick, the other a bit longer and more sparse. This second, longer coat is made up of transparent hairs with hollow interiors. Much like in the case of snow, light falling on these hairs scatters (thanks to light-scattering particles inside the hollow cores) and is reflected back out, giving the bears a white appearance. Salt particles in between the hairs left over from ocean water evaporating after a swim further enhance this effect.

NASA creates stunning visualization of melting snowflake

For the first time, researchers have created a 3D numerical model of melting snowflakes in the atmosphere. Aside from just painting a pretty, scientifically accurate picture, this could also help scientists develop better weather models and predictions.

This model reproduces key features of melting snowflakes that have been observed in nature: first, meltwater gathers in any concave regions of the snowflake’s surface. These liquid-water regions merge as they grow and eventually form a shell of liquid around an ice core, finally developing into a water drop. Credit: NASA.

If there’s anything this winter has taught us, it’s that weather is still surprising. Weather predictions have come a long way, but the sheer complexity of all the elements involved makes it very difficult to create accurate models — one of those elements which adds complexity is snow.

Snow not only affects weather predictions, but it also affects remote sensing. For instance, a radar “profile” of the atmosphere will typically show a very bright layer at the altitude where falling snow and hail melt — much brighter than atmospheric layers above and below it. We don’t really know why this happens, and we don’t understand many things about how snow starts to melt high up in the atmosphere. This is where NASA’s Jussi Leinonen enters the stage.

Leinonen created a melting model for snowflakes. He started his model by observing snowflakes in nature and noting the different melting stages. First, the outer parts start to melt, creating a bit of liquid water. This meltwater gathers in any concave regions it can find, and then the different droplets merge to form a liquid shell around the ice core. Ultimately, this melted core develops into a water drops, as can be seen above.

Although snowflakes notoriously have different intricate forms, the process seems to carry out similarly, regardless of what the shape might be.

While this isn’t the first model of snow melting, it’s by far the most accurate. This improvement could lead to significant improvements in several fields of research. Taking into consideration the individual dynamics of individual snowflakes can help researchers better understand the cryosphere — the collection of the Earth’s ice sheets, glaciers, sea ice, snow cover, and permafrost.

In 2018, NASA will launch two new satellite missions, conducting an array of field research that will enhance our understanding of the Earth’s cryosphere.

The paper, titled “Snowflake melting simulation using smoothed particle hydrodynamics,” recently appeared in the Journal of Geophysical Research – Atmospheres.

For the first time in 37 years, it snowed in Sahara

An amateur photographer has captured the dry, barren, Sahara desert in an unlikely situation: covered with a white layer of snow.

The Sahara is the largest hot desert in the world (technically, the Arctic and the Antarctic are also deserts, and they’re both larger).  The average high temperature exceeds 38 to 40 °C or 100.4 to 104.0 °F and sand temperatures are even higher – though nights are much colder. However, it is a myth that the nights are cold after extremely hot days in the Sahara and overall, average temperatures range between 13 °C or 55.4 °F and 20 °C or 68.0 °F. Needless to say, precipitations are extremely scarce and snow is almost a myth. In fact, it’s only the second time in living history it snowed in the Sahara.

Amateur photographer Karim Bouchetata captured the rare phenomenon in photos, saying that the white snow looks spectacular on the bright orange dunes. The snow stayed on for almost a day, which is even more impressive.

“Everyone was stunned to see snow falling in the desert; it is such a rare occurrence,” Mr Bouchetata explained. “It looked amazing as the snow settled on the sand and made a great set of photos. The snow stayed for about a day and has now melted away.”

The last major snowfall – if you can even call it that – hit Ain Sefra in February 1979 when it snowed for a whopping 30 minutes.

Just in case you’re wondering, this isn’t a sign that global warming has slowed its course – in fact, the contrary might very well be true. At this time it’s too early to draw any conclusions.

If you want to see more photos or follow mister Bouchetata, you can do so on his Facebook page.

Climate change is making the Arctic red — and we should be very worried about it

You’ve heard of yellow snow, but there is another shade you should fear even more: called pink, red or watermelon snow, researchers warn that this phenomenon is a worrying testament of drastic melting in the Arctic.

Red snow algae.
Image credits Iwona Erskine-Kellie.

Red snow isn’t new. The phenomenon was observed by the first arctic explorers, and it was initially believed to be caused by iron oxides permeating the snow. Since then, however, it has been established that the hue is a product of red algae that bloom in frozen water. A new study published in the journal Nature Communications shows that these blooms are causing the snow to melt faster and they’re only going to grow more rapidly as climate change causes Arctic snow to melt more.

One property of snow is high albedo, meaning it reflects a large proportion of incoming light instead of absorbing it as heat. The study found that over a 100-day period, the algae-rich snow has a 13% lower albedo than white snow. The catch is that while these algae bloom naturally, man-made global warming puts them on a positive feedback loop — higher average temperatures mean more snow is melting each year, providing the water that algae feed on, which in turn cause the snow to melt.

“As we infer from our data, melting is one major driver for snow algal growth,” the study notes. “Extreme melt events like that in 2012, when 97% of the entire Greenland Ice Sheet was affected by surface melting, are likely to re-occur with increasing frequency in the near future as a consequence of global warming. Moreover, such extreme melting events are likely to even further intensify the effect of snow algae on surface albedo, and in turn melting rates.”

That’s because the glacier melt, disproportionately driven by the rise in global temperatures, is effectively watering the red algae, says lead study author Steffi Lutz of the University of Leeds.

“The algae need liquid water in order to bloom,” she said. “Therefore the melting of snow and ice surfaces controls the abundance of the algae. The more melting, the more algae. With temperatures rising globally, the snow algae phenomenon will likely also increase leading to an even higher bio-albedo effect.”

As temperatures continue to rise, the Artic will keep taking on a bloody shade. Maybe it’s allergic to climate change.

Electrical concrete could de-ice by itself

An innovative type of concrete has the potential to save lives and millions off taxpayers’ money.

Credits: Chris Tuan, University of Nebraska-Lincoln

Especially in these frosty times, we all understand how troublesome snow and ice can be, especially on the road. This is where this concrete enters the stage.

The secret ingredient is a bunch of steel shavings and carbon particles that make about 20% of the entire mixture. These add-ins do nothing to weaken the concrete’s structural resistance, but they can conduct electricity, which means they can be heated.

The idea is to incorporate this type of concrete in key places, which have the highest risk of accident.

“De-icing concrete is intended for icy bridges, street intersections, interstate exit ramps, and where accidents are prone to take place,” said Dr. Chris Tuan, a professor of civil engineering at the university who designed the material.

Chris Tuan, professor of civil engineering at the University of Nebraska-Lincoln, stands on a slab of conductive concrete that can heat itself through electricity.

Of course, this would make the material much more expensive than regular concrete. A cubic yard of this material costs about $300, compared to $120 per cubic yard of regular concrete. However, in the long run, this might actually save money, because de-icing chemicals are hugely expensive themselves. Furthermore, salt, which is most commonly used in de-icing erodes concrete, can cause holes, rusts cars and has a significant detrimental effect on both the plants and the animals in the area. All these sum up at several billion dollars per year.

There’s also another hidden advantage – if we electrify parts of roads, then it could become much easier to power up electric vehicles. Also, by replacing the limestone and sand typically used in concrete with a mineral called magnetite, Tuan has shown that the mixture can also shield against electromagnetic waves, protecting against unwanted intrusions.

“We invite parties that are interested in the technology to go in there and try to use their cell phones,” said Tuan, who has patented his design through NUtech Ventures. “And they always receive a no-service message.”

But the main idea remains reducing the risk of accidents and saving lives. According to the US Road Weather Management Program, there were over 500,000 crashes in the past 10 years caused by snowy or frozen concrete, resulting in 2000 fatalities. This means that 200 lives a year could be saved with this pavement.

The technology itself is not new; electrified concrete has been used on a 150-foot bridge near Lincoln, Nebraska. The bridge was inlaid with 52 slabs of de-icing concrete in 2002 and has successfully defrosted itself ever since, without the need for further chemicals. Now, Tuan wants to convince airports to use it, and for good reason.

“To my surprise, they don’t want to use it for the runways,” Tuan said in a statement. “What they need is the tarmac around the gated areas cleared, because they have so many carts to unload — luggage service, food service, trash service, fuel service — that all need to get into those areas … They said that if we can heat that kind of tarmac, then there would be (far fewer) weather-related delays.”

In the meantime, he’s enjoying the benefits of this technology himself.

“I have a patio in my backyard that is made of conductive concrete,” he said with a laugh. “So I’m practicing what I preach.”