Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 18 of 18 for “"quasi-geostrophic model"”.
-
Adjoint data assimilation in an open ocean barotropic quasi-geostrophic model
A barotropic quasi-geostrophic ocean model with open boundaries was used to model a system of mid-ocean eddies. A simplified adjoint assimilation scheme was tested to see if sparse velocity data could be assimilated into the model at regular intervals. In between the times for data assimilation, …
-
Nonlinear Solutions to a Two-Layer Quasi-Geostrophic Model of the Gulf Stream
… in baroclinic instability, an inviscid 2-layer quasi-geostrophic model is studied.</p> <p>The linear solution is obtained by methods of normal mode and Fourier-Laplace transforms. It is found that the set corresponding to the continuous spectrum is null and the set corresponding to the discrete …
-
Measurements of a barotropic planetary vorticity mode in an eddy-resolving quasi-geostrophic model using acoustic tomography
… in a 2-layer, flat bottom, steady-wind driven quasi-geostrophic circulation model to investigate whether the analysis of acoustic travel time changes can detect large-scale barotropic oscillations. Time series of sea surface elevation and upper and lower layer meridional currents are generated …
-
Assimilation of altimeter data in a quasi-geostrophic model of the Gulf Stream system : a dynamical perspective
… of altimeter data in a numerical ocean model have been investigated. The model used for this study is a quasi-geostrophic model of the Gulf Stream region. The data that have been assimilated are maps of sea surface height which have been obtained as the superposition of sea surface …
-
Assimilation of altimeter data in a quasi-geostrophic model of the gulf stream system : a dynamical perspective
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1993.
-
The Dynamic Stability of The Stratosphere and Mesosphere (Atmosphere)
… motions have been examined in a spherical quasi-geostrophic model extending from the surface up to 80 km to investigate the stability of zonal motions in the stratosphere and mesosphere. Two sets of calculations were performed.
-
Vortices in sinusoidal shear, with applications to Jupiter
… sinusoidal background shear flow in a 1.75 layer quasi-geostrophic model. Trying to find vortex structures by integrating the Hamiltonian system has the drawback that the vortices lose enstrophy by filamentation and numerical dissipation, while continuing to deform and wobble. Adopting the local …
-
The Genesis and Evolution of African Easterly Waves
… Ocean are investigated with a moist multi-level quasi-geostrophic model. The origin of African waves is first re-examined as a linear instability problem of a general basic zonal flow with/without a parameterized latent heating. The method of eigenvalue-eigenfunction analysis is used. The …
-
Vortices in sinusoidal shear, with applications to Jupiter
… sinusoidal background shear flow in a 1.75 layer quasi-geostrophic model. Trying to find vortex structures by integrating the Hamiltonian system has the drawback that the vortices lose enstrophy by filamentation and numerical dissipation, while continuing to deform and wobble. Adopting the local …
-
PRINCESS AND THE PEA: THE IMPACT OF ROUGH TOPOGRAPHY ON DYNAMICS OF LARGE-SCALE SURFACE CIRCULATION PATTERNS
… not properly represented in coarse-resolution models. This study investigates how ocean floor roughness, at the kilometer scale, influences the double-gyre circulation by utilizing a two-layer quasi-geostrophic model. Using Radko’s sandpaper theory, bottom drag is parameterized to capture the …
-
Stability of large-scale oceanic flows and the importance of non-local effects
… current on the beta-plane is performed using a quasi-geostrophic model in order to determine the existence of radiating instabilities, a type of instability that propagates energy away from its origin region by exciting Rossby waves and can thus act as a source of eddy energy for the ocean …
-
Jets, mixing, and topography in the Southern Ocean
… their transport properties. Through a quasi-geostrophic model we investigate the properties of jets that form over a zonal slope in bottom topography, and find that the jets become tilted, aligning perpendicular to the large-scale barotropic potential vorticity gradient. As the jets …
-
Flow over finite isolated topography
One and two layer models are used to study flow over axisymmetric isolated topography. Inviscid or nearly inviscid flow in which non-linear effects have order one importance is considered, and both the effects of β and finite topography are included. A one-layer quasi-geostrophic model is used to …
-
Residual overturning circulation and its connection to Southern Ocean dynamics
… experience deep convection. I used a two layered model and a rectangular single-basin model to show that the basin width, in combination with scalings for the overturning circulation make the overturning relatively weaker in the wider basin, priming it for a convection shut down. In addition to …
-
Stability of large-scale oceanic flows and the importance of non-local effects
… current on the beta-plane is performed using a quasi-geostrophic model in order to determine the existence of radiating instabilities, a type of instability that propagates energy away from its origin region by exciting Rossby waves and can thus act as a source of eddy energy for the ocean …
-
Adaptive observations : idealized sampling strategies for improving numerical weather prediction
… idealized system with a three-dimensional quasi-geostrophic model and a realistic data assimilation scheme. Several issues are addressed, including whether adapting observations has potential to improve forecasts, how observational resources can be optimally allocated in space and time, how …
-
Horizontal vorticity redistribution and vortex alignment in developing and mature tropical cyclones
… of vertically-coherent vortex structures in geostrophic turbulence. For small to moderate vortex tilts, a simpler and more insightful linear model for unforced vortex alignment is presented. This model provides the basis for a deeper understanding of the dynamics of rapidly-rotating, …
-
Nichtlineare Dynamik atmosphärischer Zirkulationsregime in einem idealisierten Modell
… Zirkulationsregimen versteht man bevorzugte quasi-stationäre Zustände der atmosphärischen Zirkulation auf der planetaren Skala, die für eine bis mehrere Wochen persistieren können. Klimaänderungen, ob natürlich entstanden oder anthropogen verursacht, äußern sich in erster Linie durch …