Why is it windy?

When the air pressure in one area is different from that in another area, wind will form. When the temperature is high, the air will rise, the air pressure in the original area will decrease, and high-density cold air will flow to fill the position below the warm air flow. The flow of this gas is wind. In some parts of the earth, the wind will keep blowing. This is the prevailing wind, which determines the climate pattern on the earth.

Night land wind

At night, the temperature on the land drops faster than that on the ocean. Cold air will sink above the land and push towards the ocean, while the air above the ocean is still warm, so it will rise. When cold air moves to the ocean instead of warm gas, it produces a breeze from the land.

Daytime sea breeze

On a hot and sunny day, the warm air over the land rises and is replaced by the cold air moving from the ocean to the land, thus producing the sea breeze.

How is the wind generated?

When hot air rises, the air pressure in the original area decreases, and the air will move here from the surrounding areas with high air pressure.

When the cold air drops, a high pressure area will be generated, and the air in the high pressure area will move to the low pressure area.

The earth's trade winds

The wind blows from the high pressure area to the low pressure area. The trade wind is a kind of wind that blows from the subtropical high at latitude 30 degrees to the equatorial low near the ground. This kind of wind appears regularly in a fixed area with the same direction, so it is very "credible", so people call it the trade wind. In the northern hemisphere, the wind blows from northeast to southwest, which is called "northeast trade wind"; In the southern hemisphere, the wind blows from southeast to northwest, which is called "southeast trade wind".

wind speed

The wind blows from the center of the high pressure area to the center of the low pressure area. The closer the two centers are, the greater the wind speed between them. The wind speed is divided into 0- 12*** 13 grades according to the wind power.

The wind direction bag is used in small airports to show the pilot the wind force and direction. The wind sac is slack, indicating that the wind is weak. When the wind is strong, the wind pocket will bulge and face the direction of the wind.

High above the clouds

Clouds can provide us with the best clues about the recent weather conditions. When the temperature is high, moist air from the earth's surface will rise into the air and then cool down. When cooled to a certain extent, the water vapor in the air will become small water droplets. This process is called condensation. Countless water droplets gather together to form a cloud.

Fish Scale Day

Cirrocumulus is sometimes called "Fish Scale Day" because the patterns they form are very similar to fish scales. This cloud is composed of ice crystals, and a "fish scale sky" appears, indicating that the weather state is unstable.

Types of clouds

There are three main types of clouds: furry cumulus clouds, layered clouds with several layers, and feathered wave clouds. These three basic shapes of clouds will also be combined to produce other shapes of clouds.

Cumulus clouds sometimes look like floating cotton balls. In dry and sunny weather, they will form on land. If they get together, it may rain.

Depending on the temperature, the size of the cloud is different. If a cloud is blown into cold air, more water vapor will condense and the cloud will become bigger. If the cloud is blown into the hot air, some water droplets will be evaporated and the cloud will become smaller.

Mawei cloud

Most clouds are made up of countless water droplets, but cirrus clouds (or horsetail clouds) are made up of ice crystals. This is because they are formed at high altitudes, where the temperature is extremely low.

cumulonimbus

Cumulonimbus (or anvil cloud) is a large thunderstorm cloud with flat top and vertical extension. They often thunder and lightning.

altocumulus clouds

Cumulus clouds are a mixture of ice and extremely cold water. They look like flat white or gray clouds. They sometimes indicate that there will be a thunderstorm at the end of a long hot weather.

Dark clouds will cover the whole sky and the sun. Rain clouds can bring rain or snow.

Think about it.

If you put a mirror above the steam in a thermos. What will you see in the cold mirror? This is the process of condensation. It is also the process of cloud formation.

On a cold and sunny night, the ground tends to cool down quickly, because there are no clouds in the sky to save heat. When the air near the ground cools, water vapor condenses into tiny water droplets and forms fog.

If fog forms in areas full of smog or pollution, such as big cities, it will produce smog.