Saturday , April 17 2021

4 questions about the strange climate of winter were answered



Editor's Note: The extreme cold weather can produce unusual phenomena, from the so-called sea smoke to waves of the sea. As explains the atmospheric scientist Scott Denning, these amazing events are caused mainly by the behavior of the water at very cold temperatures.

Why are the waters of the lake and oceanic waters appear steamy during cold weather?

There are three phases, or states, of water: solid ice, liquid water and steam of gaseous water. Even in extremely cold weather, liquid water can not be cooler than the freezing point (about 32 degrees Fahrenheit), so that the surface of the ocean is much warmer than the # 39; air that is on top.

Many water evaporates from the warmest ocean to the coldest dry air above. As soon as this invisible gas increases even slightly above relatively hot water, it touches a much colder air and can not contain much vapor, so that the vapor is condensed into microscope droplets. liquid water to air.

Some call the astonishing clouds caused by condensation just above the winter ocean or the "marine smoke" lakes. It is a better time than steam. Real steam is a very hot water vapor, that is, the water in the gas phase, which is invisible.

Lake Michigan at 39th Street Harbor in Chicago on January 30, 2019.
AP Photo / Nam Y. Huh

The viewers of the time seem to be very enthusiastic about thunder. What is it and why is it rare?

Thunder is a sound boom created when a ray causes the air to expand faster than the sound speed. The jet is formed by static electricity blackouts between the clouds and the ground. The friction that forms this static is usually caused by "thermal" that grows rapidly in floating air during hot summer days, which is why torrential storms are common in summer.

Air can not be increased from the cold winter because the cold air is dense, so the winter thunderstorm is quite unusual. Thundersnow happens when the cold air really blows from above to the north. This cold air is denser than air to the surface, so it literally falls, and pushes the surface on the surface. This can create exactly the same type of static load as a summer electric storm, and BOOM – thundersnow! This only happens with a dramatic change in temperature, such as the focus of an Arctic cold front.

Episodes of Thundersnow in New England, March 8, 2018.

How frequent is the ocean freezing out of the polar regions?

Salt water has a freezing point lower than fresh water, so we put salt in our streets and sidewalks to melt ice in winter. Seagrass is enough salt because it really has to be frozen, around 28 F. It is quite unusual for seawater to freeze in the continental United States, Arctic winter.

When sea water is frozen, most of its salt is reduced to the ocean water below it. That is why people in the Arctic can melt marine ice for drinking water. As small pieces of fresh water ice are formed on the surface of the ocean, the remaining water is more saline and salt, making it harder and harder to freeze .

But sometimes, when it has been extremely cold, small ice creams form on the surface of the ocean. The waves break, so the surface can become like a wavy lagoon. For anyone who wants to overcome the cold, it is wild to be by the shore and see the smoky sea smoking with its slow speed surfing. In the dust, it is so cold that the floating ice crystals converge and solidify towards the marine gel.

Slushy Surf Nantucket, Mass., January 5, 2018.

Scientists have discovered that Mars is also snowy. How are they different from snow on Earth?

The atmosphere on Mars is an almost pure carbon dioxide, which we know as the main greenhouse gas that is driving climate change here on Earth. But the atmosphere of Mars is much thinner than ours, so it does not catch much heat. In a pleasant Martian summer day, temperatures can reach 70 F and then fall to less than 100 F the same night.

The winters are even colder there. It gets so cold in the polar winters on Mars that the air freezes, making small snowflakes of carbon dioxide to the size of the red blood cells, which stacks deep enough to make dry ice polar caps.

A frozen carbon dioxide table in the south pole of Mars.
NASA

During the long polar night, around a third of the total Mars atmosphere falls under the snow. This makes a partial vacuum, sucking the winds of the summer hemisphere of the planet in the winter hemisphere to make up for the difference. In the spring, these winds on a planetary scale reverse the direction, since the dry ice goes back to the gas and begins to fall to the other end of Mars.

Beyond the solar system, the "ice giants" planets and many of their moons have large amounts of water and carbon dioxide – much larger amounts than all our oceans. But on Earth, dry ice can not be formed above less than 110 F. So there will never be snow from carbon dioxide on our planet, just water frozen in all its forms.


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