What are the wonderful cloud phenomena?

From early winter to early winter, we often find that foggy days in the morning are mostly sunny, which is what we often say.

"Ten Fogs and Nine Sunnies" refers to late autumn, winter and early spring, when fog mostly occurs on sunny days. Does fog have anything to do with sunny days? What does it matter? To understand these problems, we must start with the causes of fog.

Fog refers to the ice crystals condensed by tiny water droplets or water vapor suspended in the air near the ground when the temperature drops. According to the data, according to the causes, fog is generally divided into four types:

(1) radiation fog. On a clear, windless or breezy night, ground radiation cooling condenses water vapor in the air layer near the ground. The fog is thickest before sunrise, and gradually dissipates or rises to stratus with the increase of ground temperature after sunrise. Its thickness is generally 100 ~ 200m, and its thinnest is only 2 ~ 3m.

(2) advection fog. Warm air moves to the colder underlying surface, and the water vapor under it condenses into fog. The emergence, disappearance and development of advection fog mainly depend on the characteristics of warm and humid advection. Generally speaking, it is wider, thicker and longer than radiation fog, and its diurnal variation is not obvious. Advection fog is formed when tropical warm and humid air mass migrates in high latitude and cold areas in winter. When the continental warm air mass moves to the colder sea surface in spring and summer; In winter and autumn, when the warm ocean air mass moves to the colder land; When the warm and humid air on the ocean moves to the intersection of the cold sea surface and the cold and warm ocean currents.

(3) Evaporation fog. When the cold air moves to the warmer water surface, the water surface evaporates faster, making the water vapor saturated and forming fog.

(4) frontal fog. It is a fog formed by the evaporation of rainfall before the warm front and the saturation of the lower air.

Obviously, the "fog" referred to here should be "radiation fog". It is formed because on a clear night, there is no cloud or partial cloudy, the atmospheric inverse radiation is weak, and the ground insulation effect is poor. The intense radiation cooling on the ground makes the water vapor in the atmosphere near the ground condense and form fog when it is cold. At the same time, because there is no cloud and it is partly cloudy, the weakening effect of the atmosphere on solar radiation is reduced, especially the reflection effect of clouds is weakened, and more solar radiation directly reaches the ground, so the temperature is higher and the weather is sunny in most days.

An angry popsicle

In hot summer, the heat is pressing, so it's very comfortable to eat a popsicle! Have you ever found that popsicles are often "angry" when they are taken out of the refrigerator?

Very interesting. Usually only hot things get angry. Why do popsicles get angry?

The temperature in summer is much higher than that of popsicles. Popsicle will melt when it meets air, and when it melts, it will absorb a lot of heat from the surrounding air, so the temperature of the air will drop. Usually the air contains a certain amount of water vapor, which is saturated or supersaturated due to the sudden drop of temperature. In other words, the air around the popsicle can't hold as much water vapor as it used to because of the temperature drop. In this case, the excess water vapor will form tiny water droplets and form a floating water droplet cloud, which will turn into white water vapor after being irradiated by light.

So do clouds, fog, rain and snow. The water in rivers, lakes and seas, after being irradiated by sunlight, constantly turns into steam and floats in the air. Air containing water vapor is heated and rises to a certain height. A cloud that condenses into suspended water droplets when it meets cold air is called a cloud. When the weather is cold, the water vapor near the ground can form a cloud of suspended water droplets. This is fog. So clouds and fog are essentially the same. Under the right conditions, the small water droplets in the cloud continue to merge into large water droplets until the rising airflow can't hold down, and then fall down to form rain. If it is winter, these water droplets will crystallize into snowflakes and fly all over the sky. However, the condensation of saturated water vapor in the air must have its condensation "core", that is, dust floating in the air, which is one of the necessary conditions to promote the formation of clouds, fog, rain and snow.

The secret of clouds greatly inspired the British physicist Wilson. After research, he invented a device called "Cloud Room" in 1894, which was filled with clean air and saturated vapor of alcohol (or ether). If you break into an invisible charged particle, it will become the core of "cloud" condensation and form fog spots, thus showing the "footprint" of particle movement. Therefore, scientists can observe the movements and changes of elementary particles (electrons, protons, etc.). ) invisible to the naked eye through the "cloud room". At the same time, many new elementary particles were discovered. Wilson's cloud room has made outstanding contributions to the study of the micro-world. 1927 won the nobel prize in physics.

Fog on the car glass

In autumn and winter or rainy days, after all the windows of the car are closed, there will be a lot of water mist, which is caused by the low temperature outside the car and the high temperature inside the car. The physical principle is that there is a lot of water vapor in the car, which will liquefy into small water droplets when it meets cold car glass. The way to remove it is to blow it with cold air of air conditioner for one or two seconds without being too cold. If it is particularly cold, you can turn on the warm air of the air conditioner, which takes more than 10 seconds to remove. Here is a method of defogging.

In rainy and snowy weather, it is not necessary to use cold wind or internal circulating wind to remove fog, as long as you are ready to remove fog and smear it on the windshield before this. The preparation method of mist removal is very simple. Find a small vessel, squeeze in a little detergent, add water at the ratio of 1: 10, then dip it in absorbent cotton or soft cloth and apply it to the inside of the front and rear windshields (including the window glass at the rearview mirror). After drying, no matter how heavy it rains outside, use suede or soft dry cloth to wipe off the residual fibers left on the windshield. If you catch up with the weather with too much humidity and large temperature difference between inside and outside the car, you can slightly increase the proportion of detergent.

In addition, many things related to household washing can also be used as substitutes, which can achieve very good defogging effect, such as melon and fruit cleaning liquid, hand sanitizer, soapy water, washing powder (after dissolution), bath lotion, shampoo and so on.

Nobel Prize in Physics

The Nobel Prize in Physics is a kind of Nobel Prize, which was established according to Nobel's will. The Nobel Prize was founded with part of the legacy of Alfred bernhard Nobel, a famous Swedish chemist and inventor of nitroglycerin explosives.

The Nobel Prize in Physics aims to reward those scientists who have made outstanding contributions to the field of human physics. The award is presented by the Royal Swedish Academy Science Award. Candidates for the annual prize are recommended by Swedish or foreign academicians of the Royal Swedish Academy of Natural Sciences, members of the Nobel Committee for Physics and Chemistry, scientists who have won the Nobel Prize in physics or chemistry, and scientists who hold permanent or temporary positions in Uppsala, Lund, Oslo, Copenhagen, Helsinki University, Caroline Medical College and Royal Institute of Technology.