Weather change is closely related to people's life. Modern people have paid more and more attention to the weather. Listening to or watching the weather forecast has become a part of people's life. However, as the saying goes, "the weather is unpredictable". It is difficult to predict the wind and rain. Why can the weather be predicted?
In fact, atmospheric changes are regular. Weather forecast is to use meteorological observation data, apply the principles and methods of meteorology, and predict the weather conditions in a certain period of time in the future according to the current and recent weather situation.
Weather forecasts have existed since ancient times. The ancients summed up many weather proverbs through long-term observation and accumulation of experience. For example, "the morning glow does not go out, and the sunset glow travels thousands of miles" is a kind of weather forecast. However, proverbs are based on experience, and many proverbs later proved to be limited, and even some are incorrect. Due to the rapid changes of atmospheric phenomena and their physical processes and complex influencing factors, in addition to the interaction between various scale movements of the atmosphere itself, the sun, ocean and surface conditions all affect the movement of the atmosphere. Therefore, even now, it is quite difficult to predict the weather accurately.
The weather forecast is made by the meteorological observatory and released to the public through various channels. At present, the main ways to spread weather forecast are television, newspaper, Internet, mobile phone short message, meteorological telephone, etc.
An important tool for forecasting weather is the weather map. Meteorologists can predict the future weather conditions by analyzing the motion law of the weather system on the weather map. Weather map is a special map filled with meteorological elements at the same time. Weather maps are mainly divided into three types: ground weather map, high-altitude weather map and auxiliary map (such as section map). The surface weather map is drawn four times a day, using the observation data of 2:00, 8:00, 14:00 and 20:00 Beijing time (i.e. 18:00, 0:00, 6:00 and 12:00 universal time); The high-altitude weather map is drawn twice a day, using the observation data of 8:00 and 20:00 Beijing time (i.e. 0:00 and 12:00 universal time).
With the progress of computer technology, the core tool of the meteorological station is the numerical weather forecast made by computer. According to the process and characteristics of atmospheric evolution and various physical processes in the earth atmosphere system, scientists designed mathematical models and compiled programs accordingly. Using these mathematical models and inputting meteorological data, we can use computer to simulate atmospheric processes and predict the state of atmospheric motion in a certain period of time in the future. The future weather situation is usually drawn on the forecast map by computer for meteorologists to forecast the weather. In addition, meteorologists should also study satellite cloud images and modify the prediction results in combination with local terrain, seasonal characteristics and experience.
In terms of the length of time limit, weather forecast is usually divided into three types: short-term weather forecast (1 ~ 3 days), medium-term weather forecast (4 ~ 9 days) and long-term weather forecast (10 ~ 15 days or more). CCTV broadcasts mainly short-term weather forecasts every day.