Two Different Points of View on the Description of Atmospheric Motion, and Recoasideration on the Causality between Motion and Pressure Field

[摘要] 1. From the equations of fluid motion, it may be thought that the fluid motion occurs as the result of existing pressure field.There may be, however, another point of view such that the deformation of pressure field may be caused as the result of fluid motion.In the atmosphere, for example, the pressure atz nearly equals to and so varies when the distribution of density (_??_) changes (as the result of at-mospheric motion). But there has been found no type of equation, which denotes the atmospheric motion from the latter point of view.2. Equations of atmospheric motion of Navier-Stokes are:where l is the Coriolis' parameter.Using the Fourier's integral theorem, the solution, w≡u+iv (i denotes Fi), is expressed in an infinite series: whereThis solution shows, of course only formaly, that the wind is composed of many components, as if each of which is caused as the result of variation in the pressure field. But, as cited above, this consideration is merely a formal one.Expanding the solution and neglecting the small terms of higher order, we get the following equations: whereThese - I should like to name “Equations of variation in the field of pressure.” - are completely the same in form as the equations of motion.Solving these equations, we get G(≡ G1+iG2) as a function of wind velocity and its variations in an infinite series.Neglecting the higher order delivatives, the equations of motion are deduced conversely.

[学科分类] 大气科学