What is Cold Dew Wind ? What will the cold dew wind affect?

After the invasion of cold air in autumn, it caused a significant cooling and reduced rice yield. In southern China, it mostly occurs during the "cold dew" solar termHence the name "Cold Dew Wind" (also known as "Social Wind"). It will affect the planting and yield of rice crops.

Here's a closer look at the cold dew wind

Introduction to Cold Dew Wind

If the average daily temperature drops below 22 for more than two days, it will cause the late rice to empty the husk and deflated grains, resulting in a decrease in yield. Because it generally carries northerly winds when it cools, it is called "cold dew wind" in the locals.

1. The types of cold dew wind are generally divided into:

1) Damp-cold type: the cold air from the north to the south meets the gradually weakening warm and humid airflow, usually with continuous cloudy days with little rain and low temperatures.

2) Dry and cold type: affected by the cold air southward, the relative humidity is less than 60%, characterized by sunny cold and dry, the average temperature is relatively low, there is more sunlight, strong radiation and high temperature during the day, and the temperature will become lower at night.

2. Classification of cold dew and wind.

Generally, based on the daily average temperature, daily minimum temperature, and rainy days, there are two grades of mild and severe, and the data corresponding to the two grades are shown in the table below.

Cold dew and wind hazards

Cold dew winds are generally associated with cold air activity, and can easily be caused when strong cold air from the north moves south and stays in the south for a long time. At present, there are still no effective preventive measures.

Cold dew wind is the main meteorological disaster in the late growth stage of late rice. The effects of cold dew wind on late rice are mainly manifested in three aspects:

1. Affect the speed of heading, so that the heading is slow, and even the ears cannot be completely extracted.

2. Affect the flowering, pollination and fertilization of spikelets, and form empty grains.

3. Affect the normal grain filling development of rice grains and form deflated grains.

The main factors affecting the heading and flowering of late rice are temperature and wind, and drying will only affect fruit setting under cold conditions. Experiments show that when the wind force is greater than 3 or more and the relative humidity is less than 60, the harm will be greater.

Cold dew wind is the natural enemy of late rice growth, and a slightly too strong cold dew wind can cause 10-20 empty deflation rate. Although it is not as harmful as typhoons and heavy rains, the process of a cold dew wind can affect millions of mu, or even tens of millions of mu, of paddy fields, and the total loss is quite amazing.

"Cold dew wind" is the phenomenon of empty husks and flat grains of late rice in South China caused by low temperature after the cold dew solar term, and the "cold dew wind" will affect the yield of late rice planted in southern China to be significantly reduced, and will be accompanied by extreme rainstorm and windy weather.

Cold dew wind is one of the main meteorological disasters during the growth period of late rice in southern China. Before and after the "cold dew" solar term in autumn every year, it is the critical period for late rice heading and flowering in South China, at this time, if it encounters low temperature hazards, it will cause empty shells and deflated grains, resulting in reduced yield, which is commonly called "cold dew wind". It will have a certain impact on the maturity of rice.

Cold Dew Wind" is also known as"Social style"It is the invasion of cold air in autumn, which causes a significant cooling in the south and reduces the yield of rice. Because it mostly occurs in southern China"Cold dew"solar terms, so it is also called "cold dew wind".

Cold dew wind refers to a kind of low temperature, dryness, accompanied by a large north wind after the cold dew festival in southern China, this weather phenomenon has a great impact on the yield of rice, it is understood that the cold dew wind is one of the main meteorological disasters of late rice in southern China, it will directly cause the reduction of rice yield and affect the harvest.

The cold dew wind is a fast-changing wind in autumn, which will make the fruit ripen faster and the air flow faster, making people feel high and cool in autumn.

The arrival of cold air in autumn is called cold dew, and dew wind refers to the social wind, which will affect the growth of rice ears.

Literally, the "cold" of Hanlu means cold, and "dew" indicates the phenomenon of water vapor condensing into dew near the ground layer, indicating the official beginning of autumn.

During the cold dew season, the direct point of the sun has left the equator, and the ground receives significantly less solar heat than in summer, and the temperature drops significantly. Most of the country, even southern China, will be affected by the cold air.

According to the tradition of our country, the cold dew is usually used as a sign that the weather is getting cooler and colder, and the dew in the middle of autumn is condensed and white, and when the cold dew is in the autumn season, it is already "the dew is cold, and it will condense into frost".

Solar term farming. The low temperature chilling injury before and after the cold dew solar term is usually called the cold dew wind, and the cold dew wind generally occurs in the south of the Yangtze River. Cold dew wind is a kind of low-temperature, dry (sometimes rainy) weather accompanied by a large northerly wind that occurs under the influence of cold air moving southward or typhoon and cold air, which is very harmful to crop production.

Cold dew wind is the main agrometeorological disaster in the late growth period of late rice in southern China.

The half month from cold dew to frost is the busy season of autumn harvest and autumn planting when autumn crops mature in golden autumn and September, and overwintering crops begin to be sown. The weather is often warm in the days and cool in the nights, and the sky is clear, which is very favorable for the autumn harvest.

October precipitation in northern China is generally only half or less of that in September, while in northwest China it is only a few millimeters to more than 20 millimeters. Drought and lack of rainfall often bring difficulties to the timely sowing of winter wheat, which has become one of the main limiting factors for high yield of dryland wheat. At this time, the southwest region is generally still rainy in autumn, and rainy weather will also occur in Jianghuai and Jiangnan in a few years, which has a certain impact on autumn harvest and autumn planting.

The above content refers to Encyclopedia - Cold Dew.

1. What is the origin of Hanlu?

Every year on October 8 or 9, when the sun reaches 195° of ecliptic longitude, it is cold dew. "The Seventy-two Candidate Explanations of the Lunar Order" says: "On the September Festival, the dew is cold and will condense.

Cold dew means that the temperature is lower than when the white dew is used, and the dew on the ground is colder and is about to condense into frost. In the cold and dew season, the vast areas of Nanling and the north have entered autumn, and the northeast and northwest regions have entered or are about to enter winter. First frost is visible in the capital Beijing at this time of year for most years, and snow has generally begun to fall in northeast China and northern Xinjiang, except for the Qinghai-Tibet Plateau, which snows all year round.

In ancient China, the cold dew was divided into three phases: "one is the guest of the wild goose; Second, the finch enters the water as a clam; Sanhou chrysanthemum has yellow flowers. "In this solar term, the wild geese line up in a line or herringbone and move south; In the late autumn, when the birds were gone, the ancients saw that many clams suddenly appeared on the seashore, and the stripes and colors of the shells were very similar to those of the birds, so they thought that the birds had become; The third "chrysanthemum yellow flower" means that the chrysanthemum has generally bloomed at this time.

2. What are the customs of the cold dew solar term?

After the white dew, the weather becomes cooler, and dew begins to appear, and when the cold dew arrives, the dew increases, and the temperature is lower. At this time, there will be frost in some areas of our country, the north has been a late autumn scene, white clouds and red leaves, occasionally early frost, the south is also autumn is getting stronger, and the cicadas are silent. Beijing people climb the custom is more prosperous, Jingshan Park, Badachu, Xiangshan and so on are all good places to climb, heavy nine climbing festival, more birds will attract many tourists.

In ancient times, dew was used as a sign that the weather was getting cooler and colder. The mid-autumn white dew solar term is "dew condensed and white", and when the autumn cold dew is already "the dew is cold, it will condense into frost".

At this time, the temperature continued to drop in most parts of southern China. The average daily temperature in southern China is less than 20, and even in the coastal areas of the Yangtze River, it is difficult for the mercury column to rise above 30 with the New Year's front, while the minimum temperature can drop below 10. Except for a few lowlands in the valleys, the average temperature in the Northwest Plateau is generally below 10 for 5 days.

Thousands of miles of frost shop, thousands of miles of snow drifting, and the autumn colors of South China are very different.

Cold dew is formed by dew. The dew in winter is very cold during the cold dew, and the cold air is known to form dew on the surface of the plant body, because the blackbody radiation shows that the plant body has heat, the air is getting colder and colder, and the physicochemical properties of the plant body fluid are getting closer and closer to the three-phase point, and the three-phase point is the liquefied state, so the cold dew is formed.

The formation of cold dew is related to the solar terms, when the white dew is in season, the cold air becomes water vapor when it is close to the ground, and small water droplets are formed on the plants near the ground. Later, people also named this period as the Hanlu Festival.

Seventy-two Candidate Explanations of the Lunar Order": "On the September Festival, the dew is cold and will condense. If the "white dew" solar term marks the transition from hot to cool, the heat has not completely disappeared, and the dew can be seen shining in the morning.

Then the "cold dew" solar term is a symbol of the cool weather, marking the transition from cool to cold, and the dew is shining, as the saying goes, "cold dew and cold dew, cold dew everywhere".

1. Cold dew is the seventeenth solar term among the twenty-four solar terms and belongs to the fifth solar term of autumn. Dou Zhi Wu; The Sun reaches the ecliptic longitude 195°; On October 7 and 9 of the Gregorian calendar every year, the festival is celebrated. Cold dew is a solar term that reflects the characteristics of climate change, after the cold dew solar term, the days are getting shorter, the nights are getting longer, the sunshine is decreasing, the heat is slowly receding, the cold is gradually growing, the temperature difference between day and night is larger, and the morning and evening feel a little chilly.

From the perspective of climatic characteristics, in the cold and dew season, the autumn in the south is getting stronger, the air is cool and the wind is cool, and the rain is less and dry; The vast areas of the north have entered or are about to enter winter from late autumn.

2, Yuan Wu Cheng's "Seventy-two Candidate Explanations of the Lunar Order" said: "On the September Festival, the dew is cold and will condense. The meaning in the work is that the temperature of the cold dew is lower than that of the white dew, and the morning dew on the ground is cold and is about to condense.

The ancients regarded cold dew as a sign of the gradual development of cold air. After the "cold dew" solar term, the heat subsides, the cold destroys the grip group gradually, and the weather gradually turns colder.

3. After the cold dew, the temperature in most parts of southern China continues to drop. The average daily temperature in southern China is less than 20, and even in the areas along the Yangtze River, it is difficult for the temperature to rise above 30, while the minimum temperature can drop below 10. Due to global warming, the date of temperature drop may be delayed.

Except for a few lowlands in the valleys, the average temperature of the Northwest Plateau is generally lower than 10 for 5 days.

1. Origin: Youqing's "Seventy-two Candidate Explanations of the Lunar Order" said: "On the September Festival, the dew is cold and will condense.

At this time, the temperature is lower than that of "white dew", and the dew is more, and the day is cold, so it is called "cold dew". The cold dew is the end of the month of the Ganzhi calendar and the beginning of the month of Xu. At night, if you look up at the starry sky, you will find that the starry sky has changed seasons, and the "Great Mars" (Antares in Scorpio) represents the height of summer, and it has sunk in the west.

As soon as the cold dew passes, the height of the sun continues to decrease, and the temperature gradually drops. The temperature drops a lot compared to the white dew solar term, and the dew on the ground is also colder, so it is likely to become frozen dew.

2. Meaning: Cold dew is the seventeenth solar term of the twenty-four solar terms and the fifth solar term of autumn. Dou Zhi Wu; The Sun reaches the ecliptic longitude 195°; On October 7 and 9 of the Gregorian calendar every year, the festival is celebrated.

The cold dew is the season of late autumn and the beginning of the month of the Ganzhi calendar. Cold dew is a solar term that reflects the characteristics of climate change. Entering the cold dew, there is cold air from time to time to the south, the temperature difference between day and night is large, and the autumn dryness is obvious.

3. After the cold dew, the cold air in the north has a certain force, and most parts of our country have disappeared under the control of cold and high pressure, and the rainy season has ended. From the perspective of climatic characteristics, it is known that in the cold and dew season, the autumn in the south is getting stronger, the air is cool and the wind is cool, and the rain is less dry; The vast areas of the north have entered or are about to enter winter from late autumn. The traditional customs of Hanlu mainly include appreciating maple leaves, eating sesame seeds, eating crabs, drinking autumn tea, etc.