Why is Tencent's weather forecast inaccurate?

Why is the weather forecast so inaccurate? Yang Guiming, a senior engineer of the Central Meteorological Observatory of China Meteorological Bureau, explained: "The accuracy of weather forecast depends on the density of observation data. However, there are only 100 sounding stations in China, which is equivalent to only one sounding station every 200 kilometers. Cloud's life is very short. A large rain cloud may rain within 10 km, but it will not be observed if the rain does not fall on the observation point. Sounding stations are sparse not only in space but also in time. Only at 8 am and 7 pm every day, the sounding balloon is raised twice for observation, and only the ground observation station is used for observation at other times. It is unpredictable that the sounding balloon rises without encountering clouds. " "It is impossible to predict what happened a few days ago in a few hours." Yang Guiming emphasized, "An observatory is like a point in a net. The bigger the network, the fewer the points, the greater the gap between points, and the higher the probability of missing or false positives. China has a vast territory and limited funds for meteorological observation, and it is inevitable that there will be false positives and false negatives. " Weather forecast: first of all, we should be prepared, and then the weather forecast without disasters is only a probability forecast. Taking precipitation as an example, it is observed that the invasion of cold air is about to rain heavily, which can accurately predict the process of this precipitation. However, it can only provide a probability of rainfall. Maybe Beijing is below 80% and Tianjin is below 50%. Yang Guiming said: "At present, the accuracy rate of regional forecast of light rain and precipitation is around 50%, with the highest reaching 80% and the lowest only over 30%. The accuracy of heavy rainfall is only about 30%. However, compared with the accuracy of only 10% in the last century, great progress has been made. " "The imagination of nature is beyond human control, and human beings can only explore and use it." Yang Guiming told reporters, "Only by understanding the weather forecast can we use it correctly. Just like earthquake warning, even if it is not accurate, you should believe it and take preventive measures. So is the weather forecast. Only when you are ready can you be safe. " Expert analysis: the accuracy rate is always greatly improved to 20 10. China will initially establish a comprehensive meteorological observation system, basically forming a platform for the industry and the whole society to enjoy meteorological information, and greatly improving the accuracy of weather forecasting. Academician Qin Dahe, director of China Meteorological Bureau, said in an interview with Xinhua News Agency that during the Eleventh Five-Year Plan period, China will also strengthen the construction of emergency systems and equipment such as comprehensive atmospheric detection, wireless information transmission, emergency meteorological information processing platform and video monitoring. For the public meteorological forecast with a forecast period of 7 days, the quality of meteorological forecast such as typhoon and rainstorm will be improved by 5% to 10%, the deviation of typhoon track forecast in 24 hours will be within 120km, the annual cold and warm climate forecast level of drought and flood will be improved by 5%, the accuracy of grain yield forecast will reach over 95%, and the atmospheric composition, lightning disaster and space weather forecast and early warning will be issued. Establish a meteorological emergency response system for major disasters, and issue early warnings of local sudden disasters such as thunderstorms, strong winds, flash floods and mudslides more than half an hour in advance. The public coverage of meteorological forecasts and warnings is 95%. Whether it is accurate or not, there is a psychological reason why people have a bad impression on the weather forecast: because of the characteristics of thinking, people always firmly remember the process that brings them unpleasant experiences and ignore the process that brings them pleasure, which is the selectivity of memory. In the weather forecast, people always remember the false positives and false negatives very clearly, but ignore the accurate forecast. Everyone will take accurate prediction for granted, and then soon forget it completely. However, when the weather station predicted that there would be no rain and it rained cats and dogs all over the street, absolutely everyone would scold: "The weather station should be laid off" and "the white-collar taxpayers of the weather station lost money". Everyone would remember this experience for a long time and enrich it into arguments to prove that the weather forecast was never accurate, so this view would be infinitely magnified. Yang Guiming said: "As a forecasting discipline, accuracy is' normal', so isn't error' normal'? Whether to believe in scientific predictions or believe in the experience summed up by the people for thousands of years, this choice still needs everyone to decide. "