Trapped mountain waves during a light aircraft accident
نویسندگان
چکیده
On 31 July 2007 a fatal light aircraft crash occurred near Clonbinane, Victoria, Australia and the official investigation concluded that mountain wave turbulence was the likely cause. This study uses three-dimensional numerical modelling and linear wave theory to examine the dynamics of mountain waves during this turbulence event and their role in generating turbulence. Analysis of the observed environment and three-dimensional idealised simulations elucidate the occurrence of trapped mountain waves and their role in creating regions of enhanced turbulence in the vicinity of the aircraft accident. Specifically, these waves perturb layers of low dynamic stability in the upstream flow, promoting turbulence in those layers. A simple ensemble of these three-dimensional simulations is also used to assess the robustness of the model solutions and demonstrate the utility of highresolution ensembles for explicit mountain wave turbulence prediction.
منابع مشابه
Mountain waves over the Hohe Tauern : In uence of upstream diabatic effects
The structure and intensity of large-amplitude trapped lee waves over the Hohe Tauern range of the Alps on 20 September 1999 are investigated through the analysis of in situ aircraft observations, airborne lidar, Global Positioning System dropsondes, rapid-scan satellite imagery, and a suite of linear and nonlinear model simulations. Observations indicate that the lee waves attained a maximum v...
متن کاملA new theory for downslope windstorms and trapped mountain waves
Mountain gravity wave theories often neglect the observationnal evidence that the large scale winds can become very small near the earth surface. This common shortcoming is related to the fact that mountain waves have a critical level near the surface in this case, making the problem extremely involved. We briefly expose here how Lott (2016) circumvents this difficulty and derive a theory where...
متن کاملEvaluation of WRF performance for depicting orographically-induced gravity waves in the stratosphere
Orographically-induced gravity (buoyancy) waves can propagate through the tropopause to the stratosphere causing disruption to high altitude aircraft operations. High altitude turbulence (HAT) was first researched using U-2 aircraft in the mid-1960s and reported by Crooks (1965). He observed that HAT from mountain wave activity was more severe than turbulence associated with jet streams or conv...
متن کاملMap Harvest P 6 Gravity Wave Breaking : 2
One of the primary objectives of MAP was to understand the generation of gravity waves from high complex terrain, and the breakdown of those waves. Several weak to moderate gravity wave events during the MAP field phase were studied with a remarkable fleet of research aircraft equipped with GPS navigation, gust probes, dropsondes and downlooking LIDAR. These data sets have been carefully analyz...
متن کاملNonstationary Trapped Lee Waves Generated by the Passage of an Isolated Jet
The behavior of nonstationary trapped lee waves in a nonsteady background flow is studied using idealized three-dimensional (3D) numerical simulations. Trapped waves are forced by the passage of an isolated, synopticscale barotropic jet over a mountain ridge of finite length. Trapped waves generated within this environment differ significantly in their behavior compared with waves in the more c...
متن کامل