We are presenting the results of a stability analysis of a background wind shear in the presence of stablestratification and of height dependent coefficients of eddy viscosity and eddy thermal conduction. It is shownthat the vertical gradients of the eddy coefficients substantially affect the phase velocities, growth rates andvertical structure of the gravity wave and are respon...

The ice cover in high mountain lakes breaks up and disappears in about an hour, in part because it has been divided into fragile vertical spindles, which are individual crystals. Contributing to this process are vertical holes in the ice remaining after particles of dust melt downward as they are warmed by the sun. Temperature profiles of lakes in the Wind River Mountains of Wyoming include tho...

Parameterization schemes for the drag due to atmospheric gravity waves are discussed and compared in the context of a simple one-dimensional model of the quasi-biennial oscillation (QBO). A number of fundamental issues are examined in detail, with the goal of providing a better understanding of the mechanism by which gravity wave drag can produce an equatorial zonal wind oscillation. The gravit...

The sounding rocket for the DELTA (Dynamics and Energetics of the Lower Thermosphere in Aurora) campaign was successfully launched from Andoya at 00:33 UT on Dec 13, 2004. Though it was cloudy at the time of launch, the Weber Na lidar was operating intermittently between 20:00 UT and 23:30 UT on Dec 12, observing Na density, temperature and meridional wind between 80 and 100 km. Throughout the ...

Parameterization schemes for the drag due to atmospheric gravity waves are discussed and compared in the context of a simple one-dimensional model of the quasi-biennial oscillation (QBO). A number of fundamental issues are examined in detail, with the goal of providing a better understanding of the mechanism by which gravity wave drag can produce an equatorial zonal wind oscillation. The gravit...

We outline a method for extracting inertio-gravity wave parameters using the autospectra and cross spectra of the horizontal perturbation winds. In essence, we define a statistical hodograph for each spectral bin, thus combining the advantages of the rotary spectrum and hodograph methods. Furthermore, we include the effects of the background vertical shear in the parameter estimation equations,...

Numerical model predictions of tropical cyclone (TC) intensity and structure suffer from deficiencies associated with initial conditions and model formulation. Here, we propose to study how errors in the HWRF model’s initial conditions impact subsequent forecasts of TC intensity and wind structure using ensemble forecasts and the ensemble-based sensitivity method. This study will utilize the se...

Coupled meteorological and Lagrangian particle models are used to examine horizontal dispersion over one to two diurnal cycles. Seven numerical experiments were run in which different portions of the atmospheric energy spectrum were included or excluded in the simulation of releases of a non-buoyant pollutant from an elevated point source. The results of the experiments indicate that vertical s...

Estimates of the effective wind speed disturbances acting on a turbine are useful in a variety of control applications. A Kalman filter-based wind speed estimator is presented here for estimation of the effective hub-height wind speed as well as linear horizontal and vertical shear components. The wind speed estimator is evaluated using an aeroelastic simulator with the National Renewable Energ...

[1] Gravity waves forced by circular bell-shaped mountains are simulated using the Advanced Regional Prediction System model for four directionally sheared wind profiles W1, W2, W2a, and W2b. W1 is eastward at the surface, while the latter three are southeastward. With the vertical shear directed northward, W1 shows an increasing speed with height, whereas W2, W2a, and W2b are first decelerated...