Interpretation
Numerical Weather PREDIX refers to a large computer by large computers under certain initial values and boundary values, based on the actual situation of the atmosphere. The fluid mechanics and thermodynamics of the evolution process, predict the method of atmospheric motion state and weather phenomena in the future.
Content
Numerical weather forecast is different from the classic weather forecast, it is a quantitative and objective forecast, because of this, numerical weather forecast first requires Establish a preferred method of numerical prediction modes and errors in the pre-report period (short, medium-term), and calculate stable and relatively faster calculations. Second, since the numerical weather forecast is to take advantage of various means (conventional observation, radar observation, ship observation, satellite observation, etc.), and therefore, it is necessary to properly make the adjustment, processing and objective analysis of meteorological data. Third, due to the calculation data of the numerical weather forecast, it is difficult to complete with manual or small computers, so there must be a large computer.
According to the actual situation of the atmosphere, in a certain initial value and boundary value, the fluid mechanics and thermodynamically equation groups describing the weather evolution process are solved by numerical calculations, and forecast the future weather. And generally useful weather methods, and combined with experience in weather forecasts, this forecast is quantitative and objective forecast. The equations used or the equations used in the equation and atmospheric kinetics are the same, that is, the equations composed of continuous equations, thermodynamic equations, water vapor equations, state equations, and 3 motion equations (see atmospheric power equations). In the equation group, seven forecasts (the speed along the components of X, Y, Z, the components U, V, W and Temperature T, the air pressure P, the air density ρ, and the harvested Q) and 7 prediction equations. The viscous force F, non-insignificated heat Q and water vapor amounts S, generally as a function of time, space, and the seven forecasts, so that the number of forecasts is the same, so the equation is Closed.
Development History
International
The world has more than 30 countries and regions to make numerical weather forecasts as the main method of making daily weather forecasts, many of which are many In addition to the short-term numerical weather forecast for 1 to 2 days, the country and region has also made a medium-term numerical weather forecast for a week.
China
China began to explore numerical weather forecasts in 1955, and in 1959, numerical weather forecast began in the computer. In 1969, the National Meteorological Bureau officially released short-term numerical weather forecast. Gradually improve the numerical prediction mode and achieve automation of data input, filling, analysis, and forecast output. Currently, in addition to completing the daily short-term numerical weather forecast business, it is preparing to make a medium numerical weather forecast.
Mode Birth
Analysis of weather maps and reading data, all of which are manual, the time spent on these work, calculating time on the electronic computer at the time ( Test) is about 10 times. In order to improve work efficiency and reduce human error, from 1954, people have proposed some ways to objectively analyze and automatically handle data with electronic computers. Soon, automation has been implemented from the recent analysis forecast. In the late 1950s, people found that the forecasts made by the mutual transit mode have great limitations, and the system intensity of the forecast changes is not large. In the future, although the effect is improved, the effect is improved, but due to the higher order of the equation used, it may be difficult to calculate if it is further considered. In 1956, A. Eliason proposed a solution for the production forecast for the original equation pattern considering gravity waves. In 1959, K. Hinkeman used the original equation model to make a success, and its effect is not less than quasi-map mode. However, he and the law of Richards are different in recognizing the nature of rapid gravity waves, and new measures (such as shortening time steps, filtering gravity parameters, etc.). In 1960, the United States launched Tayles meteorological satellite successfully found a new way to provide meteorological data in desert and ocean and other regions. With the development of the power meteorological and computing technology, the effect of the original equation mode forecast has gradually exceeded the quasi-transit mode forecast. By the early 1970s, it has been used to use it to make a business forecast (see Atmospheric mode).
Application Overview
In the 1980s, more than 30 countries and regions of the world have put numerical weather forecasts as the main method of making daily forecasts. In terms of forecasting projects, there is already air pressure, temperature, humidity, wind, cloud and precipitation; in the range, it has developed from the interstitial hemisphere and global scope including the flat-flow layer; in addition to 1 To 2 days of short-term forecasts, some countries have launched a medium-term forecast for a week. (See color map)
my country's case
made 500 bass 24-hour forecast with two layers models with graphic. At the end of 1959, the high-level field numerical prediction of the positive pressure and scam filtering mode of the Asian Europe and the northern hemisphere was started. In the spring of 1965, the National Meteorological Bureau began to post 500 Bappi forecast. In 1969, the preliminary test of automation programs for data processing, objective analysis and forecast was successful. In 1973, it began to make forecasts with the original equation. By the early 1980s, from receiving data to the drawing, analysis and output forecasting, automation, the forecast mode has developed to multi-layer original equation mode, which considers the influence of physical processes such as terrain and non-insulated heating.
There is a problem
numerical weather forecast There are still many problems still to be resolved:
The physical process of the second grid scale is < / b> Since the atmosphere is a continuous medium having a continuous moving scale, there is always a high mode resolution, there is always some movement close to or less than the grid scale (see numerical weather forecast common calculation) Methods), cannot be reflected in the mode, which is called a secondary grid process. Turbulence, convection, condensation, and radiation process include a secondary grid process. These processes have been considering these processes in numerical predictions, that is, use large-scale variables to describe the statistical effect of large-scale motion. Although this approach has achieved considerable results, there are still many unresolved issues. If parameterized does not consider the impact of large-scale on small scale and its feedback effect, the value of parameters lacks objective determination, the pattern is too sensitive to parameterization.
Non-linear equation Numerical solution Although in appropriate conditions, the numerical solution of the stable format of certain linear differential equations can be proved, and it is possible to approx Indicates the true solution of the corresponding differential equation, but for the nonlinear differential equation, two solutions may not be entirely consistent. There is already evidence that although sometimes numerical solutions are stable, but it is uniform with the true solution (which is special, the true solution is known).
Influence formation problem It includes initial value processing, satellite application and four-dimensional allocation (see the treatment and analysis of numerical weather forecast data), etc. Question, these problems have not been solved so far.
The above problem is directly encountered when the design mode is designed. But the most fundamental is also aware of the understanding of the evolution of weather, especially for the interim and long-term weather process and strong storm, and it is still not enough. In addition, although the atmosphere is detected by means of satellite and remote sensing techniques, the information to provide scarce area has a certain contribution, but the accuracy of the accuracy and forecasting of meteorological detection remains to be further improved.