How does the weather forecast achieve accurate prediction?

To say how accurate the modern weather forecast is, we can first look at how it is done.

"If the east wind doesn't follow, Tongquetai locks Er Qiao in spring". Since ancient times, from the production and life of ordinary people to wars between countries, it has been inevitably influenced and restricted by the weather at that time. The ancients' prediction of the weather is purely from the observation experience passed down from mouth to mouth for thousands of years, which is quite accidental. In modern times, with the progress of radar technology, satellite technology and computer technology, human beings can not only understand the dynamic changes of the atmosphere from the ground, but also overlook the vast surface from far away space, thus realizing the prevention of disastrous weather events and daily weather forecast.

Modern weather forecasting systems are mainly divided into ground meteorological observation stations, ground meteorological radar systems, upper atmospheric meteorological observation, meteorological satellites and data analysis centers.

The ground weather station is mainly responsible for collecting meteorological data such as air pressure, temperature, humidity, wind direction, wind speed, precipitation, snow depth, sunshine time, cloud cover and air quality. On the one hand, these data are used to summarize the atmospheric activity information collected by other means for real-time weather forecast, on the other hand, they form a database as valuable information for long-term research on climate change.

The ground weather radar system emits electromagnetic waves with centimeter wavelength to the clouds in the airspace through radar facilities established in various places, and observes the formation of condensation nuclei, ice crystals, raindrops or snowflakes in the clouds within hundreds of kilometers. The data obtained by radar and the measurement results of ground observation stations are summarized and analyzed to realize the forecast of rain and snow weather.

Meteorological observation in the upper atmosphere is mainly realized by releasing radiosondes and arranging wind profiler radar. The former can be regarded as the high-altitude version of the ground weather station, which can collect meteorological data at an altitude of about 30 kilometers. The latter can be regarded as the twin brother of ground rain and snow weather radar, which mainly measures information such as wind speed and direction at high altitude.

Meteorological satellites are located at the top of this hierarchical observation network from low to high, and are mainly responsible for monitoring meteorological changes in large areas, especially disastrous meteorological events such as typhoons.

In addition, the changing trend of clouds in a few days, the temperature distribution of seawater in a large range, and the early warning and monitoring of forest fires are just tricks of meteorological satellites. The migration of agricultural pests, the monitoring of volcanic activity and the abnormal change of seawater tide level are also inevitable.

The information processing center with supercomputer as the core can be called the brain of the whole meteorological monitoring and forecasting network. Countless trivial information collected from observation facilities and devices at all levels can be easily simulated by supercomputer operation and complex dynamic process under the comprehensive action of many factors. Supercomputers know everything from the accurate weather forecast at a certain time and place of the day to the relative amount of precipitation in the whole season and the average value of previous years nationwide.

Will the weather forecast be "inaccurate"?

Even with such a powerful forecasting system, we still have to admit that the weather forecast is sometimes "inaccurate". Why?

Generally speaking, this problem is restricted by two factors.

First of all, the modern weather forecast is not a unified city, but accurate and updated in real time. As mentioned above, weather change is an extremely complex system under the action of many factors. It is difficult for the current technology to make an accurate forecast after a few hours, but the short-term forecast accuracy in big cities is still quite high. Many people are used to listening to the weather forecast for the next day the night before that year, and it is reasonable that there will be deviations in the end.

Secondly, short-term strong convective weather such as frontal rain in summer, because of its sudden evolution law, even supercomputers often can't accurately predict it. However, the current technology is still quite sure to achieve emergency warning one or two hours before the occurrence of severe convective weather.

In terms of weather forecast, human beings have made great achievements from ignorance, the pace of technological progress is still firm, and the accuracy and effective forecast time of weather forecast will gradually improve.

How to improve the accuracy of meteorological forecast, especially rainfall forecast?

In order to reduce the situation of "inaccurate forecast" and improve the forecast accuracy, we can strengthen the investment in the hardware construction of the main meteorological forecast system. Only when we have observation and radar systems all over urban and rural areas and meteorological satellite networks covering this area can we effectively collect meteorological forecast data, and the forecast accuracy will naturally improve. For example, Japan has a small area, dense population, strong technical and financial strength, and the density of meteorological information collection system is much higher than that of ordinary countries, so it is not surprising that its meteorological forecast accuracy exceeds that of China and even other developed countries.

It seems that instead of expecting the weather forecast to be inaccurate, it is better to expect the "rain god" to come, and the hope of a sudden rain is even greater.