foggy weather

When the relative humidity reaches 100%, the water vapor in the air will condense into fine water droplets suspended in the air, which will reduce the visibility on the ground. This weather phenomenon is called fog. It is more between February and April in spring. Forming conditions: cooling, humidifying and increasing water vapor content. There are radiation fog, advection fog, mixed fog and evaporation fog.

2. Dew

Dew refers to liquid water in which water vapor in the air condenses on ground objects. In the evening or at night, due to radiation cooling, the air layer near the surface also cools down. When the temperature drops below the dew point, that is, the water vapor content in the air is supersaturated, there will be water vapor condensation on the ground or the surface of the object. If the dew point temperature is above 0℃, tiny water drops will appear on the ground or ground objects, which is called dew.

3. Frost

Scientifically speaking, frost is made up of ice crystals, similar to dew. When the relative humidity in the air reaches 100%, water is separated from the air. The only difference between them is that the dew point (the temperature at which water vapor liquefies into dew) is higher than the freezing point, while the frost point (the temperature at which water vapor condenses into frost) is lower than the freezing point, so frost will only appear when the near-surface temperature is lower than 0℃.

4. Snow

Solid water falls from the mixed clouds to the ground in the form of snowflakes. Precipitation consisting of a large number of white opaque ice crystals and their polymers. Snow is a natural phenomenon that water falls after condensation in the air, or refers to falling snow; Snow is the solid form of water. Snowfall only occurs under the influence of very cold temperatures and extratropical cyclones, so the probability of snowfall in subtropical and tropical areas is relatively small.

Step 5 rain

The water drops falling from the clouds and the water on the land and sea surface evaporate into steam. When the steam rises to a certain height, it turns into small water drops when it is cold. These small water droplets form a cloud, where they collide with each other and merge into large water droplets. When it is too big for the air, it will fall from the clouds and form rain.

6. Cloud

Cloud is a visible polymer floating in the air, which is condensed by small water droplets or small ice crystals liquefied by water vapor in the atmosphere when it is cold. Clouds are the tangible result of the huge water cycle on the earth.

The sun shines on the surface of the earth, and water evaporates to form water vapor. Once the water vapor is supersaturated, water molecules will gather around the dust (condensation nucleus) in the air, and the generated water droplets or ice crystals will scatter sunlight in all directions, thus creating the appearance of clouds. Moreover, clouds can form various shapes, and they are divided into many kinds because of their different heights and shapes in the sky.

Extended data

Influence on people

1, fog

Fog is one of the weather that has the greatest influence on human traffic activities. The deterioration of visibility in foggy days is easy to cause traffic accidents. In highway traffic accidents, traffic accidents caused by bad weather such as dense fog account for about a quarter of the total, which not only hinders traffic, but also causes great losses to the country and people's lives and property.

In this environment for a long time, the human body will inhale harmful substances, consume nutrients, cause internal injuries to the body, and easily induce or aggravate diseases. In particular, some people with environmentally sensitive diseases, such as bronchial asthma, pneumonia and other respiratory diseases, will have normal blood circulation obstruction, leading to cardiovascular diseases, hypertension, coronary heart disease, cerebral hemorrhage and so on.

2. wind

Wind energy promotes the exchange of dry and cold air and warm and humid air. Wind is a kind of natural energy. A long time ago, humans learned to make windmills, and now people still use windmills to pump water and process food.

When the wind roars, mature crops will thresh, drop fruit, lodging and cut roots. Strong winds can blow away fertile topsoil and expose the roots of crops; It will also blow sand from other places and drown fertile fields. Not only that, it can blow people down, blow houses down and take everything away.

3. Cloud

Clouds absorb heat from the ground and reflect it back, which helps to keep the earth warm. However, clouds also reflect sunlight directly back into space, which has a cooling effect. Which effect is dominant depends on the shape and location of the cloud.

References:

Baidu encyclopedia-rain

References:

Baidu Encyclopedia-Cloud

References:

Baidu encyclopedia-fog

References:

Baidu encyclopedia-Lu

References:

Baidu encyclopedia-frost

References:

Baidu encyclopedia-snow