What are the characteristics of the weather?

1. Weather phenomena mainly come from the temperature difference in different places.

On a large scale, the area near the equator receives more solar energy per unit area than other areas. From a smaller scale, different lower boundaries (such as the ground and the ocean) have different solar energy absorption efficiency due to different physical properties.

2. Temperature difference will lead to air pressure difference.

If the temperature of a surface is very high, the air on the surface will be heated and expanded, the air pressure on the surface will be reduced, and the surrounding air will be replenished, so the air movement will produce wind. In addition, Coriolis force will affect the direction of air flow. Many complex weather phenomena originated from such a simple system, such as land and sea breeze.

3. Weather density (temperature and humidity) is the difference between one place and another.

These differences may be due to the perspective of tropical sun at different latitudes at any specific position. A jet stream caused by a strong temperature difference between polar and tropical air.

In the mid-latitude region of weather system, such as extratropical cyclone, jet stream is unstable. Because the axis of the earth is inclined relative to its orbital plane, sunlight is an event that occurs from different angles at different times of the year. Once in the temperature range of 40 C (100 F to-40 F) on the earth's surface. For thousands of years, the change of the earth's orbit has affected the solar energy received by the earth and its distribution, as well as the long-term climate and global climate change.

4. The pressure difference caused by the reverse difference of surface temperature.

Weather forecast is a scientific and applied technology to predict the atmospheric conditions of a country at a certain time and place in the future. Weather is a chaotic system, and some small changes in the system can affect the whole. Throughout human history, humans sometimes try to control the weather, and there is evidence that human activities (such as agriculture and industry) have inadvertently changed the weather pattern.

Studying the weather of other planets is helpful to understand the weather on earth.

Jupiter's Great Red Spot is a famous landmark of the solar system and an anticyclonic storm with a history of at least 300 years. However, the weather is not limited to planets.

The weather in a broad sense can include the changes of gases (gaseous and ionic elements) in the whole galaxy space, and the corona of stars keeps exploding, forming a very thin gas layer in the whole solar system. It can be said that the solar wind, the mass ejection of the sun, is also a kind of weather in the solar system.

forecast

Use forecasting model to predict future weather. It still needs manpower to choose the best possible prediction model, and it also needs to consider pattern recognition skills, teleconnection, pattern efficiency and pattern deviation.

Chaos of the atmosphere, a lot of computing resources needed to solve equations describing the atmosphere, errors caused by initial measurement and incomplete understanding of atmospheric processes, all these factors make the earlier the forecast, the longer the forecast time (forecast range), the worse the forecast results. Using ensemble forecasting can help us reduce the error and choose the most possible result.

Weather forecasts have different end users. Weather warning is an important forecast for protecting life and property. Forecasting based on temperature and precipitation is very important to agriculture, so it is also valued by commodity traders in stock and futures markets. Public utilities also rely on temperature forecasting to estimate future demand.