PHYSICAL DISSIPATIVE TECHNIQUE AND ITS APPLICATION TO THE MM4

Under the traditional framework of fluid dynamics, the problem of the numerical weather prediction is often expressed as the deterministic initial value problem of the classical Newtonian mechanics. The atmosphere is, however, a many-body system, the methodology by which the system with two bodies could be precisely solved would cause bigger errors and problems when handling the many-body system by it. A kind of technique to incorporate "the irreversible thermodynamic operators",therefore, into the numerical weather prediction models is suggested in this paper, to control the evolutionary direction of the many-body system according to the constraining way of the second law of thermodynamics, and thus the forecasting accuracy of the numerical weather prediction has been noticeably improved:in (e.g.)the MM4 the averaged relative root mean square error of the fields of the temperature,humidity,height and whole wind velocity has decreased by about 13%, among which the averaged error of the 48-h forecasts has decreased by more than 20%. Since the technique to introduce the irreversible thermodynamic operator suggested in this paper is based on the physical lew that describes the dissipativity and comes out not only from the computational consideration, the technique is named as the physical dissipative technique. In view of the universality of the principle incorporating the irreversible thermodynamics operators suggested in this paper for the fluid dynamics and atmospheric numerical models, the applications and generalization of this incorporating technique would produce a great impact on the field of geophysical fluid dynamics.