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RISA New Theory for Downslope Windstorms and Trapped Mountain Waves
Publisher: American Meteorological Society
Abstract: inear mountain gravity waves forced by a nonlinear surface boundary condition are derived for a background wind that is null at the surface and increases smoothly to reach a constant value aloft and for a constant buoyancy ...
The Reflection of a Stationary Gravity Wave by a Viscous Boundary Layer
Publisher: American Meteorological Society
Abstract: The backward reflection of a stationary gravity wave (GW) propagating toward the ground is examined in the linear viscous case and for large Reynolds numbers (Re). In this case, the stationary GW presents a critical level ...
Alleviation of Stationary Biases in a GCM through a Mountain Drag Parameterization Scheme and a Simple Representation of Mountain Lift Forces
Publisher: American Meteorological Society
Abstract: The problem of the representation of the orientation of mountain forces in a GCM is examined. First a series of winter simulations is presented with the Laboratoire de Météorologie Dynamique GCM where the model ground is ...
Large-Scale Flow Response to Short Gravity Waves Breaking in a Rotating Shear Flow
Publisher: American Meteorological Society
Abstract: A two-dimensional rotating anelastic model is used to analyze the large-scale flow (LSF) response to the breaking of gravity waves (GWs) at critical levels. In the response the balanced part is separated from the inertial ...
Topographic Waves Generated by a Transient Wind
Publisher: American Meteorological Society
Abstract: The concept of linear mountain waves is generally equated with steady-state stationary waves. This essentially means that the absolute horizontal phase velocity of mountain waves is zero and that their momentum flux profile ...
Equatorial Mountain Torques and Cold Surge Preconditioning
Publisher: American Meteorological Society
Abstract: The evolution of the two components of the equatorial mountain torque (EMT) applied by mountains on the atmosphere is analyzed in the NCEP reanalysis. A strong lagged relationship between the EMT component along the Greenwich ...
Synoptic Responses to Mountain Gravity Waves Encountering Directional Critical Levels
Publisher: American Meteorological Society
Abstract: A heuristic model is used to study the synoptic response to mountain gravity waves (GWs) absorbed at directional critical levels. The model is a semigeostrophic version of the Eady model for baroclinic instability adapted ...
On the Transfer of Momentum by Trapped Lee Waves: Case of the IOP 3 of PYREX
Publisher: American Meteorological Society
Abstract: The airplane data collected between 4 and 12 km above the Pyrénées during the intensive observation period (IOP) 3 of the Pyrénées Experiment (PYREX) are analyzed again. A spectral analysis of the velocity and potential ...
Impact of Subgrid-Scale Orography on Equatorial Angular Momentum Budget and the Cold Surges in a General Circulation Model
Publisher: American Meteorological Society
Abstract: he dynamical relations between equatorial atmospheric angular momentum (EAAM), equatorial mountain torques, and cold surges are analyzed in a general circulation model (GCM). First, the authors show that the global EAAM ...
A Climatology of the Gravest Waves in the Equatorial Lower and Middle Stratosphere: Method and Results for the ERA-40 Re-Analysis and the LMDz GCM
Publisher: American Meteorological Society
Abstract: A climatology of the three-dimensional life cycle of the gravest waves in the tropical lower and middle stratosphere is presented. It shows that at periods around 10 days the gravest waves correspond to Kelvin and ...