摘要: Observations suggest that solitary and other nonlinear waves might be a source of wind shear hazard to safe flight. A derivation of the Benjamin-Davis-Ono (BDO) equation by a perturbation method is reviewed and extended to the cas... 展开 Observations suggest that solitary and other nonlinear waves might be a source of wind shear hazard to safe flight. A derivation of the Benjamin-Davis-Ono (BDO) equation by a perturbation method is reviewed and extended to the case in which the fluid is in sheared flow. For nonsheared flows, our solution for the upper layer differs markedly from Benjamin's, which doesn't satisfy his specified boundary conditions. The internal steady-state solitary wave, described by the solution of the BDO equation, is compared with a boundary layer solitary wave observed with NSSL's Doppler radar, and a 444-m-tall instrumented tower. Wave-induced vertical transport of the horizontal momentum of the strongly sheared ambient air contributed much to the observed wind perturbations and horizontal wind shear. It is shown that agreement between the theoretical results of the weakly nonlinear theory of BDO and observations of wind and temperature at the surface is coincidental because wave advection and frictional drag markedly affect wave properties. Only tall tower and Doppler radar measurements above the ground provided the necessary data to determine that the observed solitary wave was strongly nonlinear, and that it trapped thunderstorm outflow, which leaked out the rear of the wave. Wave amplitude data, for above (i.e., < or approx. = 200 m) the ground, show fairly good agreement with numerical results from strongly nonlinear theory. Wind shear produced by the solitary wave appears to be significant, even though it is 60 km from the storm that initiated it. (EDC) 收起