Content of numerical weather forecast

The numerical weather forecast is different from the classical weather forecast method, and it is a quantitative and objective forecast. Because of this, numerical weather forecasting first requires the establishment of a better numerical forecasting model (short-term and medium-term) that reflects the forecasting period and a calculation method with small error, stable calculation and relatively fast operation. Secondly, because numerical weather forecasting needs to obtain meteorological data through various means (conventional observation, radar observation, ship observation, satellite observation, etc.). ), the meteorological data need to be properly adjusted, processed and objectively analyzed. Thirdly, because there are so many calculation data of numerical weather forecast, it is difficult to complete it by hand or small computer, so there must be a large computer.

According to the actual situation of the atmosphere, under certain initial and boundary conditions, the equations of fluid mechanics and thermodynamics describing the weather evolution process are solved by numerical calculation, and the method of forecasting the future weather is obtained. Different from the weather forecast made by synoptic method combined with experience, this forecast is quantitative and objective. The equation used or based on the forecast is the same as that used in atmospheric dynamics, that is, the equation composed of continuous equation, thermodynamic equation, water vapor equation, state equation and three equations of motion (see atmospheric dynamics equation). These equations include seven predictive factors (velocity components in X, Y and Z directions, U, V, W, V and W, temperature T, air pressure P, air density ρ and specific humidity Q) and seven predictive equations. Viscous force F, diabatic heating quantity Q and water vapor quantity S in the equation are generally regarded as functions of time, space and these seven forecasting factors, so that the number of forecasting factors is the same as that of the equation, and the equation is closed.