Search Results

You are looking at 1 - 7 of 7 items for :

  • Weather modification x
  • Terrain-Induced Rotor Experiment (T-Rex) x
  • All content x
Clear All
James D. Doyle, Saša Gaberšek, Qingfang Jiang, Ligia Bernardet, John M. Brown, Andreas Dörnbrack, Elmar Filaus, Vanda Grubišić, Daniel J. Kirshbaum, Oswald Knoth, Steven Koch, Juerg Schmidli, Ivana Stiperski, Simon Vosper, and Shiyuan Zhong

underlying terrain. For example, mesoscale predictions of landfalling fronts were found to be very sensitive to small changes in incident flow, as deduced through simulations made with small modifications to the topography orientation by Nuss and Miller (2001) . Two-dimensional idealized adjoint ( Doyle et al. 2007 ) and ensemble ( Doyle and Reynolds 2008 ) model results indicate large sensitivity to the initial state as the mountain height increases, forcing wave breaking, where perturbation growth

Full access
Željko Večenaj, Stephan F. J. De Wekker, and Vanda Grubišić

homogeneous terrain, numerical models may have problems when dealing with complex terrain. Weigel and Rotach (2004) indicate that the turbulence structure is greatly influenced by the configuration of the underlying terrain. Rotach and Zardi (2007) argue that an extension and/or modification of the classical scaling for turbulence variables is required for which measurements in complex terrain are needed. A correct parameterization of boundary layer turbulence is important for a variety of

Full access
Stefano Serafin, Lukas Strauss, and Vanda Grubišić

1. Introduction Owens Valley is a narrow valley in eastern California, approximately north–south oriented and bounded by the highest portion of the Sierra Nevada (high sierra) to the west and by the White–Inyo Range to the east. Within such a valley, one expects different types of terrain-induced circulations ( Whiteman 2000 ) to occur. Dynamically driven winds [e.g., topographically channeled flow and intense downslope winds related to mountain waves] are the result of the local modification

Full access
Bowen Zhou and Fotini Katopodes Chow

-valley direction (80° azimuthal angle to the right and 260° to the left), and recorded radial velocities. 3. Model configuration and description The Advanced Regional Prediction System (ARPS) was used for the simulations. ARPS is developed at the Center for Analysis and Prediction of Storms at the University of Oklahoma ( Xue et al. 2000 , 2001 ). It is a nonhydrostatic mesoscale and small-scale finite-difference numerical weather prediction model. ARPS uses a generalized terrain-following coordinate on an

Full access
Qingfang Jiang and James D. Doyle

and wave characteristics aloft are further examined in section 5 . The results and conclusions are summarized in section 6 . 2. Observational summary a. Dependence of mountain waves on mountaintop winds and moisture The T-REX region of enhanced observations includes two nearly parallel mountain ranges, the Sierra Nevada and Inyo Mountains, with the quasi-two-dimensional Owens Valley located between the two ranges ( Fig. 1 ). A variety of ground-based instruments, including automatic weather

Full access
Juerg Schmidli, Gregory S. Poulos, Megan H. Daniels, and Fotini K. Chow

surface–atmosphere exchanges over mountainous regions are closely linked to slope and valley flows; and the effects of these flows on mesoscale fluxes need to be parameterized in numerical weather prediction and climate models (e.g., Noppel and Fiedler 2002 ; Weigel et al. 2007 ; Rotach and Zardi 2007 ). Three major mechanisms that can produce within-valley winds are thermal forcing, pressure-driven channeling, and downward momentum transport ( Whiteman and Doran 1993 ). Thermal forcing refers to

Full access
James D. Doyle, Qingfang Jiang, Ronald B. Smith, and Vanda Grubišić

Experiment (T-REX). The orographic modification of stably stratified airflow past two- and three-dimensional topography has been the focus of numerous numerical and theoretical investigations. Smith (1980 , 1989) and Smolarkiewicz and Rotunno (1989) have explored the dynamical parameter space governing the occurrence of flow stagnation and flow splitting upstream of isolated three-dimensional topography in the absence of rotation. Flow splitting, vortex shedding, and wakes are examples of

Full access