Although incorporating the horizontal diffusion into the atmospheric governing equations is a part of the dynamics of a model,it is based on the computational consideration originally,which is to overcome the nonlinea...Although incorporating the horizontal diffusion into the atmospheric governing equations is a part of the dynamics of a model,it is based on the computational consideration originally,which is to overcome the nonlinear aliasing or computational instability and smooth the physical fields at the same time.The generally used forms of the fourth-order diffusion,either linear or nonlinear, however,can not properly describe the real physical diffusion processes and thus affect the accuracy of forecasting and modeling.In this paper,based on the nature of the physical diffusion. the scheme of horizontal diffusion of the MM5 Version 3 is improved according to the second law of thermodynamics which controls the irreversable evolutionary direction of a many-body system and the potential ability of the improvement of the new scheme in modeling accuracy is revealed by introducing the technique suggested in this paper,via a theoretical case and the computational case of the hurricane Andrew that landed on Florida in 1992.展开更多
基金This work is jointly supported by the National Natural Sciences Foundation of China(49675268,40075024)and the National Key Basic Program for Developing Basic Sciences(G1998040911).
文摘Although incorporating the horizontal diffusion into the atmospheric governing equations is a part of the dynamics of a model,it is based on the computational consideration originally,which is to overcome the nonlinear aliasing or computational instability and smooth the physical fields at the same time.The generally used forms of the fourth-order diffusion,either linear or nonlinear, however,can not properly describe the real physical diffusion processes and thus affect the accuracy of forecasting and modeling.In this paper,based on the nature of the physical diffusion. the scheme of horizontal diffusion of the MM5 Version 3 is improved according to the second law of thermodynamics which controls the irreversable evolutionary direction of a many-body system and the potential ability of the improvement of the new scheme in modeling accuracy is revealed by introducing the technique suggested in this paper,via a theoretical case and the computational case of the hurricane Andrew that landed on Florida in 1992.
