Traditional Culture Encyclopedia - Weather forecast - Do weather proverbs make scientific sense?

Do weather proverbs make scientific sense?

There are many weather proverbs in our country, such as "northeast wind, rain is too great" and "Wayun, the sun kills people". People use weather proverbs to forecast the weather, and the forecast effect is often good. However, weather proverbs often have local and seasonal characteristics. Therefore, to accurately forecast the weather, we should not only pay attention to weather proverbs, but also combine the weather situation map, so as to better grasp the law of weather changes.

For example, "there is a rainbow in the east and rain in the west", which means that if people see a rainbow in the eastern sky at night, it means that the local weather is fine; If people see a rainbow in the western sky in the morning, it means it will be rainy in the local area. Is this prediction reasonable?

We know that there are sometimes some tiny water droplets in the atmosphere. When sunlight hits these water droplets, the water droplets will refract and internally reflect the sunlight. As a result, the sunlight is refracted into seven colors: red, orange, yellow, green, cyan, blue and purple, forming a beautiful colorful arc in the narrow sky, which is the rainbow. The rainbow people see is red outside and purple inside. The appearance of rainbow shows that there are both sunlight and water droplets in the atmosphere.

Most of China is located in the north temperate zone, and the westerly airflow prevails at high altitude. Affected by the westerly airflow in the upper air, the cloud system of rainfall generally moves from west to east. Therefore, if you see a rainbow in the east in the evening, it means that the rain area moves eastward and the local weather will turn fine; If you see a rainbow in the west in the morning, it means that there are more water droplets in the air in the west, the rain area will move and the weather will get worse. Therefore, it is reasonable to say that "the sun in the east rainbow and the rain in the west rainbow" is a phenomenon brought by the rain cloud system moving from west to east.

However, in other cases, this proverb does not apply. For example, in the eastern coastal areas of China, typhoons often affect summer and autumn. Typhoons often move from southeast to northwest. Therefore, if the typhoon moves westward and forms a rainbow in the sky, there will be no "rain in the East Rainbow" phenomenon, but "rain in the East Rainbow".

For another example, there is a weather proverb called "there is a hook cloud in the sky, and it will rain for three days and five days." This proverb means that if we see hook clouds in the sky, that is, clouds with silky structure, silky luster, partially dispersed and slightly curved shape (called cirrus clouds in meteorology), then the weather will deteriorate and it may rain in a few days. Why is this?

As we know, the interface between cold and warm air is called front. There is a rising movement of warm air on the front, so an area is controlled by the front, which is often cloudy and rainy. When warm air pushes the front to move to the cold air side, this front is called warm front, which will cause continuous precipitation in an area. Large-scale systematic cloud systems often appear on warm fronts. When a warm front moves to a certain place, cirrus clouds, cirrostratus, high-level clouds and nimbostratus often appear in turn. Among them, nimbostratus is thick, and the precipitation mainly occurs in the area controlled by nimbostratus. Cirrus clouds and cirrostratus do not cause precipitation, but their appearance often indicates that high-level clouds and nimbostratus will follow. In other words, it indicates that there will be continuous precipitation.

Cirrostratus is a white and transparent cloud with a bundle structure, but it is not isolated and scattered in the sky, but can cover part or all of the sky. When cirrostratus appears and the sky is dizzy, it often indicates that the weather may turn to rain. The agricultural proverb "the sun is dizzy in the middle of the night, the rain is dizzy in the middle of the night, and the wind is dizzy at noon" refers to this sign.

There is also a weather proverb called "there are carp spots in the sky, so you don't have to turn over the grain tomorrow." In other words, if there are checkerboard clouds in the sky, the weather will be fine and the sun will be strong. If you put the millet on the ground, you can dry it without turning it over. Why is this?

When there is an interface with different air density and air velocity in the atmosphere, it will cause fluctuations. At this time, the air at the peak rises and may cool into clouds; When the air in the tank sinks, no clouds are generated. This will form rows of parallel clouds. If there are two wave directions, the new wave will be superimposed on the original wave, thus forming a cloud similar to a checkerboard grid. In meteorology, we call this kind of cloud wave cloud.

If the lower atmosphere is unstable and the upper atmosphere is stable, in this case, it is particularly beneficial to the formation of Apollo clouds. Because the upper and lower layers of air are stable, it is not conducive to the formation of fluctuations. If the air in the upper and lower layers is unstable, it is not fluctuation, but convection. The unstable air layer in the lower layer and the stable air layer in the upper layer not only ensure that the disturbed air has a certain vertical movement, but also will not develop into convection. It can be seen that the appearance of wave clouds often indicates that the upper atmosphere is very stable, so it will be sunny.

However, sometimes wave clouds are connected with large layered clouds, which indicates that there will be wind and rain. Because the appearance of layered clouds is often a precursor to the coming front. Therefore, there is also an agricultural proverb: "It's a fish-scale day, and it doesn't rain when it's windy." Therefore, when wave clouds appear in the sky, we should pay attention to whether they are connected with layered clouds, and if necessary, we should look at the weather situation map to see if there is any front movement. In this way, we can accurately predict the weather in the next few days.

In the folk, there is another saying, called "dew is heavy and sunny", which means that if there is more dew in the morning, it often indicates sunny days. What is the reason?

At night or early morning in autumn and winter, we sometimes see some small drops of water on the leaves, which are dew. There is a poem that says, "Poor late September, dew like a pearl and moon like a bow." First, we need to find out how dew is formed.

We know that the air contains a certain amount of water vapor. And the higher the temperature, the greater the water vapor content; Conversely, the less water vapor content. At night and before sunrise, the temperature is relatively low. At this time, if the air is humid, the ability of air to contain water vapor will be reduced due to cooling, and some water vapor will condense into water droplets on ground objects such as leaves and roofs, thus forming dew.

Under what meteorological conditions, dew is more likely to form?

First, it is easier to form dew on sunny nights and early mornings. Because there are no clouds in the sky on sunny nights and early mornings, the heat on the ground directly radiates into space, and the heat absorbed by the atmosphere is relatively small. Therefore, the surface temperature drops rapidly, which is beneficial to the formation of dew. It can be seen that it is reasonable to "see the sun in the sky".

Second, it is easier to form dew when there is a breeze. Because the breeze can constantly bring moist air and take away the air that has precipitated water vapor. If there is no wind, it is difficult to send out humid air continuously. However, if the wind is too strong, the cold air near the ground and the warmer air in the upper layer will have a strong mixture, which will make the surface temperature higher and is not conducive to the formation of dew.

During the day, we usually can't see dew. Why? This is because after the sun comes out, the air temperature in the near-surface layer rises, and the ability of air to contain water vapor increases. At this time, dew will evaporate into steam and enter the air again.

To sum up, folk weather proverbs are a summary of people's long-term life and production experience. Weather proverbs play an important role in local weather forecast. However, we should also see that different places and seasons often have different weather proverbs. Combining weather proverbs with weather situation maps will help to obtain better forecast results.