Weather forecast broadcast in Lianhua county

Why is the weather forecast sometimes inaccurate? Experts from the Central Meteorological Observatory and the Beijing Meteorological Observatory told reporters that the weather forecast seems simple, but it is actually a huge systematic project. Weather forecast is based on atmospheric science theory, various meteorological detection methods, numerical weather forecast as the core and comprehensive judgment and analysis of forecasters. "There are some uncertainties in every link, and it is impossible for every prediction result to be consistent with reality. Improving the accuracy of weather forecast is still a worldwide problem. " First of all, human understanding of the mechanism of atmospheric motion is still limited. Cloudy days, cold days, rain and snow, wind and frost, all kinds of weather are caused by the constant movement of the atmosphere. Because of the complexity of atmospheric motion, scientists can't really describe the fine structure of atmospheric motion. Secondly, the meteorological observation network cannot be "sparse but not leaking". Meteorological exploration has developed into a three-dimensional observation system covering the ground, air and space. Ground observation stations, high-altitude observation stations, automatic weather stations, radar observation stations and weather stars form an observation network to continuously monitor atmospheric movements and changes. But this net will miss small and medium-scale weather systems, just like catching small fish in a big net, it is easy to miss. Moreover, there may be errors in the observation data. For example, the observation results of wind direction and speed are all 2 minutes average, and there may be errors. Thirdly, the numerical weather forecast model can't fully simulate the atmospheric evolution. The change of weather is the result of the change of atmospheric motion around the earth, which should conform to some laws of fluid mechanics and thermodynamics in physics. These laws can be written into mathematical equations in mathematical language. People use high-performance computers to turn the problem of weather forecast into the problem of understanding mathematical equations. This method is called numerical weather forecast, which is the core of modern weather forecast. However, at present, any set of models can not truly simulate the evolution of the atmosphere, but only approximate, and there must be errors. Fourth, there will be differences in experience and level between forecasters. The forecast results calculated by the numerical model cannot be directly used as the forecast conclusion, and forecasters have to interpret, apply and correct them according to local conditions. For example, there is Yanshan Mountain in the north and Taihang Mountain in the west of Beijing, so the weather forecast must consider the influence of topography. The personal experience of forecasters also plays an important role in the prediction and comprehensive decision-making of complex weather. Weather forecast is a very complicated system engineering. In fact, in developed countries, the phenomenon of inaccurate weather forecast often appears. In 2005, the accuracy of rainstorm forecast in the United States was only 22%, and the error of typhoon track forecast was 103 km. Song Yingjie said that he had read a foreign colleague's pamphlet, the content of which was to remind meteorological staff how to keep a psychological balance in the face of public ridicule. There is still a big gap between China and the world's advanced level in the accuracy, refinement and service level of weather forecast. Since the reform and opening up, China's meteorological cause has made great progress, and a weather forecast business technology system based on numerical weather forecast, man-machine interactive information processing system as a platform and comprehensive application of various forecasting technologies and methods has been initially established. The forecast time limit basically covers all time periods within 10 days. Ten-day weather forecast, daily rolling 7-day weather element forecast and 3-day disastrous weather regional forecast have been launched in all stations across the country. The forecast and early warning level of severe weather such as typhoon, rainstorm, gale cooling, sandstorm and high temperature has been significantly improved. 10 for many years, the score curve of weather forecast quality in China has shown an upward trend. According to the international standard, the accuracy of light rain forecast is 60%, the rainstorm is close to 20%, and the typhoon path error is about 120km. "Although there have been several big errors, overall, the forecast accuracy of the Beijing Meteorological Observatory this year is still relatively high." Sun, chief forecaster of Beijing Meteorological Observatory, said. According to him, the accuracy of the 24-hour temperature forecast (maximum and minimum temperatures) from Beijing Meteorological Observatory/KLOC-0 to March is 70.4%; 1 to April 13, and the accuracy of 24-hour rain and snow forecast is 72.2%; 65438+10-March 24 hours, the accuracy rate of gale forecast above grade 5 is 84.6%. Meteorologists also pointed out that compared with the international advanced level, there is still a big gap in the accuracy, refinement and service level of China's weather forecast. Experts from the Central Meteorological Observatory said that there is still a big gap between the level of numerical weather forecasting and the ability of independent innovation in China. There is a lack of numerical weather forecasting model that can meet the demand of refined factor forecasting, and the forecasting timeliness and fineness of the model are still far from those of the international advanced models. Professional numerical forecasting models are mainly imported from abroad. The gap between data assimilation system and developed countries is obvious, which is an important factor restricting the overall development of meteorological services in China. In addition, the release level of numerical weather forecast products in China is not high enough. The ability to forecast bad, critical and turning weather is obviously insufficient. With the development of social economy and the improvement of people's living standards, the requirements of governments at all levels and the public for the accuracy and refinement of weather forecast have also been continuously improved, which has deepened people's dependence on weather forecast information. This makes people's "hope" and "disappointment" in weather forecast increase at the same time. The probability prediction of the "last mile" is more scientific because it reflects uncertainty. Meteorologists pointed out that people think that the weather forecast is sometimes "inaccurate", and another important factor is that in the weather forecast of the United States, Japan and other countries, meteorological elements such as precipitation are probabilistic forecasts, such as "the probability of precipitation tomorrow is 70%". In China, Beijing and other places have carried out probability forecasting for a period of time, but because people are not adapted and do not understand, probability forecasting was quickly cancelled. Shi Yongyi, general manager of Huafeng Meteorological Film and Television Information Group of China Meteorological Bureau, visited the production of weather forecast programs abroad and saw meteorologists predict: "Snow may or may not fall in this area." Shi Yongxin believes that this is actually a probability prediction and a more scientific method. Experts also pointed out that the "last mile" of China's meteorological early warning information release is still not smooth, which is not only not conducive to disaster prevention and mitigation, but also objectively increases people's impression that the weather forecast is "inaccurate". Different weather systems have different predictability and timeliness. For example, for local strong convective weather (such as tornado, hail, thunderstorm and gale), it is difficult to report its specific location and intensity more than 48 hours in advance with current technology. "Strong convective weather such as tornadoes, hail, thunderstorms and strong winds often takes only a few hours from generation to end, and it is impossible to predict it for a long time in advance." Jiao said: "The time limit for developed countries to forecast strong convective weather is only ten minutes. Although the early warning time is short, the information can reach people in time. However, the' last mile' problem of early warning information in China has not been solved, and it is difficult to send early warning information to users in an effective time, so that they can take effective measures to prevent meteorological disasters. " For example, in July 2004 10, the meteorological department issued an early warning one hour in advance, but many people didn't get this information at that time, resulting in a large number of vehicles in lianhua bridge and other places being flooded by water. After the "July10" rainstorm in Beijing, the problem of weather warning by TV spots was solved. However, at present, the weather short message is charged, and the meteorological department hopes to establish a free release mechanism with the communication department, especially the mobile communication company. It takes a long time to improve the accuracy. The monitoring and early warning rate in 20 10 will reach more than 80%, and the accuracy of short-term weather forecast and atmospheric factor forecast will be greatly improved. In June last year, the State Council issued "Several Opinions on Accelerating the Development of Meteorological Undertakings", pointing out the importance and urgency of accelerating the development of meteorological undertakings. China Meteorological Bureau immediately started the reform of business technology system, with the ultimate goal of improving the level of meteorological forecasting and service capacity. In the overall scheme of technical transformation, the focus of meteorological business reform is to improve the fine forecasting business process and promote the breakthrough of severe weather and quantitative precipitation forecast; Improve the business of approaching forecast and short-term forecast, build a weather early warning and forecasting system for sudden disasters, and improve the meteorological emergency support capability for sudden events; Establish a four-dimensional data assimilation system and strengthen the numerical weather forecast and its interpretation and application. According to the goal set by China Meteorological Bureau, by 20 10, an intensive, research-oriented and open meteorological service technology system with complete functions and complete and optimized structure will be basically established to meet the national demand, and the national, regional, provincial, prefectural and county meteorological services will be arranged in an orderly manner, and the meteorological service capacity will be further enhanced and the scientific and technological level of meteorological services will be significantly improved. By then, the meteorological department will comprehensively utilize space-based, space-based and ground-based observation information to realize all-weather continuous monitoring of weather and related disasters in most areas of China, and the monitoring and early warning rate will reach over 80%. Establish short-term fine quantitative forecast service of atmospheric elements based on numerical forecast products, greatly improve the accuracy of short-term weather forecast and atmospheric element forecast, and the four-day precipitation forecast will reach the three-day forecast level in 2005; The short-term forecast quality of severe weather such as typhoon and rainstorm has been improved by 5% on the basis of 2005. (Source: People's Daily)