Yo, the weather

Hello! The weather forecast said it would rain, but it didn't. This is not a rumor.

Weather forecast is to predict the change of weather according to certain principles, but to some extent, due to various reasons, the weather is changeable and the weather forecast is inaccurate. For example:

Butterfly Effect 1960, Professor Lorenz of Massachusetts Institute of Technology studied the problem of "long-term weather forecast" and used a simplified model to simulate the evolution of weather on the computer. His original intention was to improve the accuracy of weather forecast by using the high-speed operation of computer. However, contrary to expectations, many calculations show that very small differences in initial conditions will lead to huge differences in calculation results. Lorenz used an image metaphor to express his discovery: a small butterfly flapping its wings over Brazil may cause a storm in Texas a month later-this is the famous "butterfly effect" in chaos, and children have probably heard of it. According to this theory, the accuracy of weather forecast can't be 100%.

Numerical Weather Forecast Nowadays, most weather forecasts are backed by powerful computers and complex mathematical models, instead of "seeing the weather from the clouds". Numerical weather forecast approximately represents the evolution law of the atmosphere as a set of mathematical equations. According to the initial state of the current atmosphere obtained by limited observation, the forecast of future weather or climate conditions can be obtained by solving the solutions of this set of equations. This is not the equation I learned in math class. The complexity of this equation requires a supercomputer that runs hundreds of billions of times per second to get an approximate solution. Have you found that the word "approximate" appears twice, which means that the equation and the final solution are not perfect, so sometimes there will be some errors in the final result, which is inevitable!

Have children found that the current weather forecast has a very accurate impact on forecasting large-scale weather such as typhoons and cold air heading south, all because of meteorological satellites in the sky. The satellite images sent back by meteorological satellites every day are helpful to predict the trend of large-scale weather, but the observation range of meteorological satellites is at least as large as that of a province, and it is responsible for observing the weather in the whole country. It is impossible to keep an eye on a city all the time, so satellites can't do anything about sudden extreme weather in a small area, such as thunderstorms, thunderstorms, hail and tornadoes-which is also an important reason why sudden extreme weather in these small areas is difficult to predict.