A Preparatory Attempt To Improve Meso-Scale Numerical Model By Use Of The Second Law Of Thermodynamics

The first law of thermodynamics is the theorem on conversation of energy,while the second law of thermodynamics is the theorem describing the direction of the conversion of energy. One is not dependent on the other one but the replenishment of the other one. In the current numerical model, the first law of thermodynamics and the principle of conservation of energy and matter have been taken into account adequately as the basic theories of each forecasting equation. However , although the second law of thermodynamics has also been applied in the models in some degree , it is not enough evidently. Thus in this article we will try to connect the second law of thermodynamics to the forecasting model, and try to add a restrictive condition to the thermodynamical equation in the model in order to improve the forecasting equation in some extent. In order to verify the effect, two examples have been both described by the original MM5V3 and the improved MM5V3. In each example, comparing the forecasting results, especially the simulated results of wind,pressure,temperature and precipitation, we find that the improved MM5 is better than the original one.The improvements are the increasing of relative coefficients of each variable. On synoptic chart, they were embodied that the location and direction of each isoline were both closer to the actuality. Furthermore, the forecasting results of the location and intensity of precipitation are also better than what are simulated by the unimproved MM5, and the improvement of the simulation of the pressure is the best. The comparison of the simulations of the two examples also tell us that different parameterised scheme of heating has different reaction to the added restrictive condition. It behaves that the improved simulation results of the first example are better than the second one.