What is the basic idea of the text "17 Seeing the Weather from Clouds"

"The sky in the northwest is unlocked, and the sun is bright in the Ming Dynasty": it means that on rainy days, the clouds in the northwest split, exposing a blue sky, which is called "the sky is unlocked". This shows that the local area is already at the back of the rainy weather system. As the rainy system moves eastward, the local area will stop the rain and the weather will improve.

"The sun appears now and we don't see each other for three days": it means that in spring and summer, at noon on rainy days, the clouds split and the sun appeared, but the clouds quickly gathered and thickened, which indicates that the local area is under the influence of the quasi-static front, and the air flow near the quasi-static front is strong and changeable. When the updraft is strengthened, the clouds become thicker and the rainfall increases; When the updraft weakens, the clouds become thinner and the rainfall decreases or stops; Around noon, the sun shines strongly, the upper part of the cloud is heated and evaporated, or the updraft below the cloud is weakened, and the cloud at the zenith will crack. As the sun's radiation weakens, or the updraft under the clouds strengthens, the split clouds gather again and become thicker. Therefore, "the sun appears now" often indicates that it will continue to rain. This proverb is similar to other proverbs, such as "the sun laughs, the temple is drenched" and "one light shines, the next ten feet".

"Carp spot in the sky, you don't need to turn it over tomorrow to bask in the grain" (tile cloud, it will scorch people): Carp spot refers to altocumulus translucidus, and the air mass that produces this cloud is stable. At night, when it meets downward flow, the cloud will dissipate quickly, and the next day will be sunny. However, if the cloud looks like a tiny fish scale, it is cirrocumulus. This kind of cloud mostly occurs in front of a trough of low pressure or around a typhoon, and it will be windy or rainy in the near future. Therefore, there is a proverb that "it's windy even if it doesn't rain".

"The clouds are heading east, and there is a gust of wind; Clouds go west, covered with hemp fiber ":The cloud referred to here is the low cloud in the low-pressure area. The low pressure is from west to east (in fact, it often moves from southwest to northeast). The cloud is heading west, indicating that the place is in front of the low pressure, and it will rain locally because of the low pressure; The cloud is moving eastward, indicating that the low pressure has moved over the local area, and the local area is behind the low pressure. The weather is about to clear up, and there is often a gust of wind before it clears up.

"Where the cloud hook goes, where the wind comes from": Cloud hook refers to the tail of the hooked cloud, which appears in the sky, sometimes with small hooks at the top, or arranged in rows. The upper hook refers to the direction of the high-altitude wind, which is often connected with the ground, so the direction of the cloud hook can generally tell the direction of the wind.

"The morning is covered with dark clouds, and the wind will come even if there is no rain": it means that there are dark clouds covering the sun in the southeast in the morning, which indicates rain. Because the warm and humid southeast wind blows in the morning, the temperature is higher than that of the local air, resulting in upper cooling and lower heating, and the water vapor is easy to rise into clouds. In addition, during the day, the ground is heated, and the air convection rises, which further urges the clouds to rise, and the water vapor becomes water droplets when it is cold, which may make the weather become rainy in NO FENG フウカ.

"Huang Yun is turning up and down, and it is going to lay ice eggs": Huang Yun is mostly caused by the strong rise of warm and humid air, which often causes showers and hail.

"When the mountain wears a hat, it will rain heavily": When the mountain wears a hat, it means that the air pressure is low, and the water vapor in the air mostly forms clouds at the top of the mountain. As for whether it will rain, it generally depends on the situation. If the clouds gradually decrease and thicken, the possibility of rain is high. On the contrary, if the clouds gradually rise and thin, the possibility of rain is small.

"Clouds eat under fog, and fog eats clouds and clears up": Clouds come after seeing fog, and maybe a low pressure is coming, which is a sign of rain. On the contrary, if the cloud clears, it means that the low pressure has passed and the sunny weather is coming.

"Sunset shoots at the foot, and the rain falls within three days": it means that the sun shines down from the gap in the clouds, which is called "the sun shoots at the foot", and it appears in the evening, indicating strong convection and indicating rain.

"Don't go out in the morning, but travel thousands of miles in the evening": there are no clouds in the east and clouds in the west in the morning. Sunlight shines on the clouds and scatters rosy clouds, indicating that there is plenty of water vapor in the air or a rainy system moves in, and the air is generally unstable during the day, so the weather will turn rainy; If there is a sunset glow in the evening, it indicates that the sky in the west has cleared up, and the general convection is weakened at night, and the clouds in the east that form the rosy clouds will move to the east or tend to dissipate, indicating that it will be fine.

"Long sunny, foggy and cloudy, long cloudy, foggy and sunny": it means that fog appears after long sunny, indicating that warm and humid air moves in and the air is humid, which is a sign that it is cloudy and rainy; Fog appears after a long period of overcast, indicating that the clouds in the sky become thinner, split and dissipate, and the ground temperature decreases, which makes the water vapor condense into radiation fog. When the fog disappears after sunrise, it will appear sunny.

In the morning of warm season, if a fort cloud appears on the horizon, it indicates that the moist atmosphere at this height is already very unstable. At noon, once the low-level convection develops, the upper and lower unstable levels will combine, which will produce strong convection movement, form cumulonimbus clouds and cause thunderstorms. So there is a proverb "pagoda clouds in the morning and rain cats and dogs in the afternoon".

In addition, clouds with weather omen often have certain continuity, seasonality and locality in the evolution process. Clouds in the sky move continuously from a distance in the order of cirrus, cirrostratus, stratosphere and nimbostratus, and gradually change from less to more, from high to low, and from thin to thick, which indicates that rainy weather will come soon; On the contrary, if the clouds change from low to high, from thick to thin, and from layered to scattered clouds, there will be no rainy weather. In the morning of warm season, if there are isolated clouds (light cumulus clouds) with flat bottom and convex top in the sky, or white broken clouds (broken cumulus clouds) with fast movement, it indicates that the middle and low air layers are relatively stable and the weather is fine.

In addition, the color of the cloud can also indicate certain weather. For example, the color of the hail cloud is first white with a black background, and then red appears in the cloud, forming white, black and red tangled clouds, and the edge of the cloud is khaki. Black is caused by the sun's inability to penetrate the clouds; White is the result of cloud body's non-selective scattering or reflection of sunlight; Red and yellow is the phenomenon that some cloud droplets (with a diameter of between one thousandth and one hundredth of a millimeter) in the cloud selectively scatter sunlight. Sometimes rain clouds are pale yellow, but the clouds are even in color and do not churn. There are also many proverbs that predict hail from the color and shape of clouds. For example, there are proverbs in Inner Mongolia, such as "If you are not afraid of the dark in the clouds, you are afraid of the dark and red in the clouds, and you are most afraid of the white worms under Huang Yun". In Shanxi, there are "Huang Yun turns over and hails; Stir the clouds and hail in groups; There are proverbs such as "When the clouds fight, it will hail" and "The black clouds in Huang Yun are red and red, and the clouds are tossed and turned, and there are many hail disasters". There are also sayings such as "Dark clouds roll into a ball in the afternoon, and the wind, rain and hail come together", "The sky is yellow and sultry and the clouds turn over, and the Tianhe water roar to prevent ice eggs", which all indicate that when the air convection is strong, the clouds develop rapidly, like thick smoke, and the clouds roll up and down, it is easy to hail.

Second, it is good to travel by looking at the clouds.

Weather conditions are very important for outdoor activists, because most of the bad weather is caused by sudden changes in the weather. In order to enjoy a happy outdoor life, while listening to the weather forecast, tourists need to master certain climate knowledge, learn to read the clouds and know the weather, so that they can calmly cope with the abnormal changes in the weather.

here are 1 cloud forms, with the word "product" indicating that the shape of the cloud is massive (regardless of size) and the word "layer" indicating that the sky is full of gloomy clouds. Each type gives the approximate altitude of the distribution, and the higher the clouds, the better the weather. In polar regions, the same type of clouds will appear in the lower altitude sky.

cirrocumulus: Small round cumulus clouds, which look like ripples, are often called "fish scale days". Usually, the altitude is 5 ~8 meters, which generally indicates sunny weather.

Cumulus: Similar to cirrocumulus, it indicates good weather, but it covers a wider area, with thicker clouds and dark white. It usually appears after heavy rain and is suspended at an altitude of 5 ~6 meters.

Cumulonimbus cloud: It is a low-level Lei Yun with dark clouds. Tower clouds can be as high as 6 meters, and the flat clouds at the top are called anvil tops. Cumulonimbus clouds often bring strong storms, thunder and lightning. The upper layer resembles a false cirrus cloud and the top layer resembles a false rain cloud.

Cumulus: It's easy to identify, fluffy white clouds, like wadding, floating in the air. If we are separated from each other, it means another beautiful sunny day, but if it grows bigger and bigger and there are more and more front ends, it is likely to bring a sudden rainstorm. Cumulus clouds in the blue sky at sea usually indicate that they are not far from land, and the height is generally not more than 2,5 meters.

cirrus cloud: a high-level wispy cloud formed by ice crystals, which is why it looks pure white, and is often called ponytail cloud. They also usually mean sunny weather, 5,-9, meters high.

cirrostratus: It's made of ice particles and looks like white clouds. These are the only clouds that will glow around the sun or the moon. If cirrostratus expands, it means sunny weather; If cirrostratus shrinks, it means it will rain; If the sky is covered with cirrus clouds, the sky above cirrus clouds darkens and gradually forms cirrocumulus, which indicates the coming of rain and snow.

high-level cloud: it looks like a gray curtain under the sunlight or moonlight. If wet air approaches, the cloud disk disappears, and the clouds become thicker and darker until it rains, which can reach 2,5 ~ 6, meters high.

nimbostratus: It's a low-level dark cloud hanging in the air, which means there will be rain within 4 hours, usually lasting for several hours.

stratocumulus: a low-level imbricate cloud that usually covers the whole sky. The clouds are thin and the sunlight can be transmitted. They may bring thunderstorms, but they usually disappear in the afternoon, leaving a clear and bright blue sky. The height is less than 2,5 meters.

stratus cloud: the lowest cloud layer is like a dense fog hanging in the air, which is often mistaken for mountain dense fog when it first appears. They are not natural rain clouds, but they can also form drizzle. If it gets thicker and thicker at night and covers the morning sky, it will usually be a sunny day, and the height will not exceed 2,5 meters.