How is the weather forecast calculated?

The most traditional data are air pressure, temperature, wind speed, wind direction, humidity and other data. Collected by professionals, amateurs, automatic weather stations or buoys on the ground or at sea. The World Meteorological Organization coordinates the timing of data collection and sets standards. These measurements are made every hour (METAR) or every six hours (SYNOP).

Meteorological data is becoming more and more important. Meteorological satellites can collect data from all over the world. Their visible photos can help meteorologists study the development of clouds. Their infrared data can be used to collect the temperature of the ground and cloud top. By monitoring the development of clouds, we can collect the wind speed and direction at the edge of clouds. However, the accuracy and resolution of meteorological satellites are not good enough, so the ground data is still very important.

Data assimilation

In the process of data assimilation, the collected data are combined with the numerical model used for prediction to produce meteorological analysis. It is the best estimate of the atmospheric state and a three-dimensional representation of temperature, humidity, air pressure, wind speed and wind direction.

Data weather

Calculate the change of atmosphere with time according to the results of physics and fluid mechanics.

Output processing

The original output of model calculation can usually be processed before it becomes a weather forecast. These processing methods include using statistical principles to eliminate the deviation in known models, or referring to the calculation results of other models for adjustment.

Important tool

The important tool of weather forecast is weather map. Weather maps are mainly divided into ground and high altitude. The weather map is densely covered with various weather symbols, which are filled in after being translated according to the weather codes of various places.

Each symbol represents a particular weather.

Symbols representing clouds, such as cirrus, cirrocumulus, cirrostratus, Altocumulus, nimbostratus, Cumulonimbus, etc.

Symbols representing weather phenomena include: thunderstorm, tornado, fog, continuous heavy rain, light snow and light showers.

In addition, there are symbols indicating the change of wind direction, wind speed, cloud cover and air pressure.

All these symbols are filled in their respective geographical positions in a unified format. In this way, all meteorological elements, such as wind, temperature, humidity, air pressure, clouds, cloudy, sunny, rain, snow and so on. Can be observed simultaneously in a wide area. , can be filled in the weather chart. So as to form weather charts representing different times. With these weather charts, forecasters can further analyze and process them, and display the analysis results with lines and symbols of different colors.

The analysis of the ground weather map includes: delineating the regional scope of important weather phenomena (such as precipitation, gale and blizzard). ), draw the positions of cold front, warm front and quasi-static front, draw the isobar of the whole picture, and mark the center and intensity of low pressure and high pressure. After such analysis, we can clearly see the pressure situation at that time from the picture: where is the high pressure, where is the low pressure, and where is the confrontation zone between cold and warm air.

The meteorological elements filled in the high-altitude weather map are the heights of all points on the same isobar surface, so contour lines separated by a certain value are drawn through analysis. After the contour line is drawn, we can see the pressure situation at that time: where is the trough of low pressure and where is the ridge of high pressure. Then draw an isotherm and mark the cold and warm center. From the configuration of heating and cooling center, low pressure trough and high pressure ridge, forecasters can make a general judgment on the future air pressure situation.

With the development of meteorological science and technology, some meteorological stations have used advanced detection tools and forecasting methods such as meteorological radar, meteorological satellites and electronic computers to improve the level of meteorological forecasting and achieved remarkable results. According to reports, since 1966, typhoons in tropical oceans all over the world have almost escaped the "eyes" of meteorological satellites. Satellite cloud images are very effective for monitoring and early detection of severe storms and severe disastrous weather.

manufacturing process

(1) according to the information provided by the relevant departments, the national meteorological situation map (that is, the background map of the weather forecast program) is made on the computer.

(2) The host stood in front of a blue screen to explain the weather (there is only one secret for the host to master the location of each area-rote learning)

③ The film and television center performs image synthesis, and replaces the blue screen in process ② with the chart in process ① on the computer;

(4) The film and television center transmits the completed program to CCTV.