大尺度加热与东西风带中不稳定扰动的激发

文中通过一些简化假定,得到了包括非绝热加热的一参数模式。导得加热存在下的正压不稳定的必要条件是β-d2u/dy2+q2u+S2H/K=0,研究了大尺度加热对东西风带不稳定扰动及定常波型扰动的作用。结果指出,加热场对东西风带正压不稳定扰动的影响与加热和流场的相对配置有关。此外,大尺度加热可以在西风带激发出定常波型扰动,而在东风带只能产生衰减型扰动。激发西风带定常波型扰动的非绝热加热场的水平半径尺度,应大于Lc=(u/β)1/2。最后还考虑了摩擦的作用。

LARGE-SCALE HEATING AND EXCITATION OF UNSTABLE DISTURBANCES IN THE WESTERLY AND EASTERLY CURRENT

It is the purpose of this paper to investigate the effect of large-scale heating on the excitation of unstable disturbances. It is found that influence of heating on the barotropic unstable disturbances depends on the disposition of the heating and the flow field; in the westerly current the stationary wave patterm disturbances may be excited by heating and in the easterly current decaying disturbances may be excited only; the horizontal scale of diabetic heating which excite wave pattern disturbances must be R≥(u/β)1/2.At last, the effect of friction on disturbances is studied.