Can there be frost at zero degrees? Will there be frost at 3 degrees above zero?

Frost is formed by water vapor, how does water vapor condense into frost? The Southern Song Dynasty poet Lu Benzhong wrote in "Southern Gezi Lusi": "The post invades the oblique moon, and the river bridge spends the evening frost.

Lu You wrote in "Frost Moon" that "the dry grass is frosty and white, and the cold window moon is new." This means that the frost appears on a clear moonlit night in autumn. There are no clouds in the autumn evening, the ground is like a quilt, the heat dissipates a lot, the temperature drops suddenly below 0, and the little water vapor on the ground will condense on the stream, bridge, leaves and soil, forming fine ice needles, and some become hexagonal frost flowers.

Frost can only be formed on a sunny day, and people say that "thick frost and fierce sun" is this reason.

Summary: The moisture in the sky will condense when it is cold, and some will become rain and some will fall into frost. In the thick of autumn, it is not too cold, so it does not snow, but the temperature is much lower than in summer, so there is less rain and more frost.

The origin of frost].

Every year around October 23 of the solar calendar, when the sun reaches the yellow longitude of 210 degrees, it is the frost fall in the 24 solar terms. Frost is the last solar term of autumn, the transition from autumn to winter. In the autumn evening, there is a lot of heat dissipation on the ground, the temperature drops sharply below 0 degrees, and the water vapor in the air directly condenses on the ground or plants to form fine ice needles, and some become hexagonal frost flowers, white in color and loose in structure.

The Seventy-two Candidate Explanations of the Lunar Order said about frost fall: In September, the air is solemn and condensed, and the dew is frost. "Frost fall" means that the weather is gradually getting colder and the dew condenses into frost.

In ancient China, frost was divided into three phases: first, the jackal was a sacrificial beast; Second, the grass and trees are yellow; Three stinging insects are salty. The jackal began to capture prey, sacrifice beasts, sacrifice the heavens with the beasts, and sacrifice the righteousness of autumn gold with the beasts; The leaves of the trees on the ground are yellow and falling; The stinging insects also remain motionless in the burrow, hanging their heads and entering a state of hibernation.

In ancient China, frost was divided into three phases: first, the jackal was a sacrificial beast; Second, the grass and trees are yellow; Three stinging insects are salty. "During this solar term, the jackals display their prey before eating.

Every year around October 23 of the solar calendar, frost falls when the sun reaches 210 degrees of ecliptic longitude. Frost falls indicate that the weather is colder and the dew condenses into frost. "Seventy-two Candidate Explanations of the Lunar Order":

In the middle of September, the air is solemn and condensed, and the dew is frosty." At this time, hoarfrost has appeared in the Yellow River Basin of our country, and on the fertile field, a piece of silver ice crystals is shining, and the leaves are yellow and falling leaves.

In the ancient book "Twenty-four Solar Terms", it is said: "The air is solemn and the frost falls, and the yin begins to condense." It can be seen that "frost falls" indicates that the weather is gradually getting colder and frost is beginning to fall.

In meteorology, the first frost that occurs in autumn is generally called the "early frost" or "first frost", and the last frost that appears in spring is called the "late frost" or "final frost". The interval from the final frost to the first frost is the frost-free period. There are also early frosts called "chrysanthemum frost", because chrysanthemums are in full bloom at this time, and Su Shi, a great writer in the Northern Song Dynasty, has a poem that says:

Thousands of trees are swept yellow, and only Hibiscus is alone."

Of course, 0 degrees Celsius can produce frost. When the temperature drops below 0 degrees Celsius or the frost falls at 0 degrees Celsius, it occurs.

。Because the temperature is lower than the ground and the surface of the object, there is water vapor condensed into white crystals, which is hoarfrost; The water vapor content is low, and there is no frost, which is called black frost; There is frost damage to crops, called frost.

Frost is a relatively common agrometeorological disaster, which occurs in winter and spring, mostly caused by cold waves moving southward, and the temperature drops sharply below zero degrees Celsius in a short period of time. Or after being affected by the cold wave, the weather turns from cloudy to sunny on the night, due to the strong radiation cooling of the ground, which is often said to be "worse".

The temperature after autumn decreases significantly with the frequent invasion of cold air, especially in the clear and windless night or early morning, the radiation heat dissipation increases, the ground and plant surface temperature drops rapidly, when the plant body temperature drops below 0, the cells in the plant will be dehydrated and frozen, and suffer from frost hazards.

Frost is the time of year when the temperature difference between day and night is the largest. EnterFrost falls on the solar termAfter that, the cold air activities affecting China became more and more frequent, and the temperature difference between day and night increased rapidly.

Especially in Jiangnan and South China.

The fluctuation of temperature is becoming more and more obvious; The western bush or some areas in the north and northeast have already shown an early winter scene of "cold wind and falling leaves".

During the frost period, generally from late October to early November, the warm and humid air has been marginalized as the cold and dry air gradually dominates the world, and many of the weather characteristics of summer and early autumn have withdrawn, and the weather is relatively simpler. Around the beginning of winter, there are often strong winds and cooling weather, and some places enter winter in a relatively short period of time.

Frost customs

1. Group and chrysanthemum appreciation

The first frost that appears in autumn is called "morning frost" or "chrysanthemum frost" because it is a good time to see chrysanthemums when they are in full bloom. The frost seepage season is the time when the autumn chrysanthemum is in full bloom, and many places in our country should hold a chrysanthemum meeting at this time, enjoy the chrysanthemum and drink, in order to show the reverence and love for the chrysanthemum. Especially in the south.

The climate is mild, and during the frost falls, the fields are caught.

Green, orange, orange, orange and green, autumn chrysanthemum.

2. Eat persimmons

In the frost season, persimmons should be eaten in some places, which can not only keep warm from the cold, but also replenish muscles and bones. Persimmon is generally fully ripe before and after frost, at this time the persimmon skin is thin and the flesh is delicious, and the nutritional value is high, but it should be noted that it should be stopped in moderation.

The above content refers to Encyclopedia - Frost Fall.

During the frost season, if the cold air is strong and the surface temperature drops to 0 or lower, and the water vapor in the air near the surface reaches saturation, it will directly condense on the ground or near the ground to form fine ice crystals.

Related Notes:The formation of frost is related to weather conditions, as well as to the properties of the object to which it is attached. The temperature of the surface of the object is very low and the temperature of the air near the surface of the object is relatively high, then there is a temperature difference between the air and the surface of the object, if the temperature difference between the surface of the object and the air is mainly caused by the radiative cooling of the surface of the object.

When the warmer air comes into contact with the colder surface, the air cools, and the excess water vapor will precipitate when it reaches supersaturation. If the temperature is below 0°C, the excess water vapor condenses into ice crystals on the surface of the object, which is called frost.

In the early morning of the cold season, the blades of grass and clods of soil are often covered with a layer of frost crystals. They sparkle in the rising sun and melt when the sun rises. People often refer to this phenomenon as "frosting".

Flipping through the calendar, in late October every year, when the temperature is around 0 degrees, there is always a solar term of "frost fall". We've seen snow, we've seen rain, but no one has seen frost. In fact, frost does not fall from the sky, but forms in the air near the ground level, usually when the temperature is around 0 degrees.

Welcome to Hope it helps you.

Frost is not falling, it is the process of water vapor in the air encountering a low temperature below 0 degrees Celsius, and directly changing from a gaseous state to a solid state, which is called condensation. The area south of the Yangtze River is humid and frosty in winter, and there is almost no frost in the dry winter in the north.

There will be no frost at 3 degrees above zero. Frost refers to the white ice crystals formed by the air close to the ground that is affected by the radiative cooling of the ground, and cools to below 0 degrees Celsius, and condenses on the ground or objects. Therefore, frost only forms when the temperature near the surface is below 0.

Frost is formed by the condensation of water vapor in the air close to the ground on or near the ground; And the lower the temperature, the density of the air.

The larger, the greater the specific gravity.

The meteorological conditions for the formation of dew and frost are clear and breezy nights. Clear nights are conducive to rapid radiative cooling of ground or ground objects. The breeze can make the radiative cooling fully carried out in the thicker air layer, and the air close to the ground can be replaced, ensuring that there is enough water vapor ** condensation.

When there is no wind, there is not much condensation water vapor that can be used to supply condensation, and when the wind speed is too strong, the turbulence is too strong, so that the air on the ground is strongly mixed with the warmer air on the upper layer, resulting in the slow cooling of the air on the ground, which is not conducive to the formation of dew and frost. For frost, in addition to the formation of radiative cooling of beams, it is beneficial to its formation after cold advection or when cold air is gathered in depressions.

There will be no frost at 3 degrees above zero. Frost refers to the white ice crystals formed by the air close to the ground that is affected by the radiative cooling of the ground, and cools to below 0 degrees Celsius and condenses on the ground or objects in Yuanchang. Therefore, frost will only form when the temperature near the surface is below 0.

Frost is formed by the condensation of water vapor in the air close to the ground on or near the ground; And the lower the temperature, the denser the air will be, and the greater the specific gravity.