Traditional Culture Encyclopedia - Weather inquiry - What is the symbol of the weather forecast? What is the symbol of the corner below the two points above?

What is the symbol of the weather forecast? What is the symbol of the corner below the two points above?

This symbol in the weather forecast indicates a sandstorm.

Is the sandstorm a sandstorm or a sandstorm? Sandstorm is a sign of desertification. It refers to a disastrous weather phenomenon that strong winds roll up a lot of dust on the ground, making the horizontal visibility less than 1 km. It has the characteristics of suddenness and short duration, low probability and great harm.

Among them, sandstorm refers to a sand-laden storm formed by strong wind blowing a large amount of sand near the stratum; Sandstorm is a storm formed by strong winds, which brings a lot of dust and other particles into the sky.

The following figure shows the commonly used weather and corresponding symbols.

Extended data

Weather symbols are special symbols representing various weather phenomena, clouds and sky conditions. Includes weather phenomenon symbols for observation and recording and weather graphic symbols for media communication. Common weather is wind, snow and rain.

1, the cause of the wind

The direct cause of the wind is the uneven distribution of air pressure in the horizontal direction. Wind is comprehensively influenced by different factors such as atmospheric circulation, topography and water area, and its manifestations are various, such as monsoon, local sea-land wind, valley wind and foehn wind. Simply put, wind is the directional movement of air molecules.

To understand the causes of wind, we must first understand two key concepts: air and air pressure. The components of air include nitrogen molecules (accounting for 78% of the total air volume), oxygen molecules (accounting for about 2 1%), water vapor and other trace components. All air molecules are moving at a very fast speed, colliding with each other and anything on the horizon.

2. The reason for the snow

There are two conditions for the formation of snowfall:

One condition is that water vapor is saturated. The maximum amount of water vapor that air can hold at a certain temperature is called saturated water vapor. The temperature at which air reaches saturation is called dew point. When saturated air is cooled to a temperature below the dew point, the excess water vapor in the air becomes water droplets or ice crystals. Because the saturated water vapor content of ice surface is lower than that of water surface, the water vapor saturation required for the growth of ice crystals is lower than that of water droplets.

That is to say, water droplets can grow only when the relative humidity (relative humidity refers to the ratio of the actual vapor pressure in air to the saturated vapor pressure of air at the same temperature) is not less than 100%; As for ice crystals, they tend to grow when the relative humidity is less than 100%. For example, when the temperature is -20℃ and the relative humidity is only 80%, ice crystals can grow.

The lower the temperature, the less humidity is needed for the growth of ice crystals. Therefore, in the high-altitude and low-temperature environment, ice crystals are more likely to be produced than water droplets.

3. The reason for the rain

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

There are many reasons for the rain, and the manifestations are also unique, such as Mao Mao rain, continuous rain, pouring rain and so on. Rain is the most important fresh water resource in human life, and plants thrive on the moisture of rain and dew. But the flood caused by rainstorm will also bring great disaster to mankind.

weather symbol

1, sunny: it means that there are no clouds or scattered clouds in the sky, but the cloud amount is less than110, which is called sunny. Sometimes there are very high and thin clouds in the sky, but they have little effect on sunlight.

2. Cloudy: It can be said to be cloudy when the cloud amount of low clouds accounts for 4/ 10 ~ 7/ 10 of the sky area or the cloud amount of high clouds accounts for more than 6/ 10 of the sky area.

3. Cloudy day: It is called cloudy when the amount of clouds in the middle and low clouds accounts for more than 8/ 10 of the sky area. Cloudy days are dark days, and little or no sunlight can penetrate the clouds.

4. Fog: refers to a large number of water droplets or ice crystal particles suspended in the air near the ground. When this aggregate reduces the horizontal visual distance below 1000 meters, it is called fog; When the visible distance drops to 1000 ~ 10000 meters, it is called light fog.

5, light rain: 4 hours rainfall is less than 1 0.0mm or1hour rainfall is less than 2.5mm, which is called light rain.

6. Moderate rain: it is moderate rain when the rainfall within 24 hours is 10.0 ~ 24.9 mm or 1 hour is 2.5 ~ 8.0 mm. ..

7. Rainstorm: Rainstorm is called when the rainfall in 24 hours is less than 25.0 ~ 49.9 mm or 1 hour reaches 8. 1 ~ 15.9 mm. ..

8. Rainstorm: Rainstorm is called when the rainfall reaches or exceeds 50.0mm in 24 hours and 1 hour reaches or exceeds16.0mm.. Heavy rain occurs when the rainfall reaches 100.0 ~ 199.9 mm; When the rainfall reaches 200.0 mm, it is called a torrential rain.

9. Thundershower: refers to sudden rainfall accompanied by lightning, which is characterized by short rainfall time, sudden start and end, and great changes in precipitation intensity. Intermittent precipitation accompanied by lightning and thunder.

10, hail: it is a kind of solid precipitation. Refers to spherical or conical ice cubes with a diameter of 5.0 mm, and it will rain heavily in the clouds. The shape is also irregular. The monomer is called hail block, which consists of transparent and opaque layers. The diameter of large hailstones can reach 19 cm.

1 1. Freezing rain: raindrops freeze on the ground below 0℃, also known as rain songs (frozen by fog drops, called rime), and often fall off the power lines, freezing the road surface and affecting communication, power supply and traffic.

Baidu encyclopedia-weather symbols

Baidu encyclopedia-weather