Starting from the primary equations and using the method of multiple timescale, theauthor derives three stages of baroclinic atm ospheric motion, i.e. the stage of geostrophicadaptation the stage of quasi-geostrophic ...Starting from the primary equations and using the method of multiple timescale, theauthor derives three stages of baroclinic atm ospheric motion, i.e. the stage of geostrophicadaptation the stage of quasi-geostrophic potential vorticity adaptation and the balanced state.The potential vorticity adaptation comes into being through the process in which long wavesdisperse unbalanced energy. It is demonstrated by means of energy variation that under non-linear condition, the quasi-geostrophic evolution in which the potential vorticity conserves in-evitably leads to a quasi-balanced state. In this balanced state isolines of energy, stream lines andisohypses run parallel with each other. The first order approximation of this balanced stateis the so-called balance equation. Thus in nonlinear atmosphere this balanced state is moregeneral than the quasi-geostrophic balance. This result is significant for mid-range and long-range weather evolution.展开更多
文摘Starting from the primary equations and using the method of multiple timescale, theauthor derives three stages of baroclinic atm ospheric motion, i.e. the stage of geostrophicadaptation the stage of quasi-geostrophic potential vorticity adaptation and the balanced state.The potential vorticity adaptation comes into being through the process in which long wavesdisperse unbalanced energy. It is demonstrated by means of energy variation that under non-linear condition, the quasi-geostrophic evolution in which the potential vorticity conserves in-evitably leads to a quasi-balanced state. In this balanced state isolines of energy, stream lines andisohypses run parallel with each other. The first order approximation of this balanced stateis the so-called balance equation. Thus in nonlinear atmosphere this balanced state is moregeneral than the quasi-geostrophic balance. This result is significant for mid-range and long-range weather evolution.
