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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Quasi-stationary atmospheric responses to large-scale forcing

Kang, In-sik 27 March 1984 (has links)
A time-dependent, spectral, barotropic model and a similar two-layer primitive equation model are developed to investigate the planetary-scale wave responses to various types of large-scale forcing: vorticity and heat sources, and sea surface temperature (SST) anomalies. Both models are linearized about the zonal mean states of January climatology. The characteristics of forced Rossby waves are extensively studied based on both the barotropic model experiments and the theory of Rossby wave propagation on the sphere (Hoskins and Karoly, 1981). In particular, both model and theoretical results show that the responses are dominated by ultra-long wave components (zonal wavenumber m = 1, 2, and 3), and that the large responses occur for vorticity sources located at the subtropics and at the high latitudes near 45°N. The model experiments for the wavenumber-dependent sources located at various latitudes show that the ultra-long waves behave like a north-south seesaw between the high and middle latitudes (m = 1) or between the high latitudes and subtropics (m = 2). The north-south seesaw of zonal wavenumber 1 component is in good agreement with that observed by Gambo and Kudo (1983). The responses of long waves (m > 3) are, however, localized in the source regions with relatively small amplitudes. The characteristics of baroclinic responses to prescribed heat sources located at various latitudes are also examined. Over the source latitudes baroclinic responses are dominant; however, the remote responses have a barotropic structure. The north-south seesaws appearing in the barotropic model are also observed in the baroclinic model. A series of baroclinic model experiments, in which surface heat fluxes and internal heating are computed in terms of the model variables, are also conducted to investigate the linear effect of sea-surface temperature (SST) anomalies on the atmospheric circulation. The experiments for prescribed SST anomalies, taken equal to twice those of Rasmusson and Carpenter (1982), simulate many aspects of the associated observed atmospheric anomalies, and suggest, therefore, that a large part of the atmosphere's responses occur via linear dynamics. It is also suggested that the rather weak responses in the North Pacific are due to the lack of a zonally varying basic state. In the case where the SST anomalies are located in the middle latitudes, the responses are about five times smaller than for the tropical SST anomalies. This result is also fairly consistent with the GCM experimental results by Chervin et al. (1976). Subsequent experiments, using climatological January SSTs in the tropics, suggest that the tropical Pacific SST can be an important factor in maintaining the climatological standing waves, at least over the western half of the Northern Hemisphere. / Graduation date: 1984
2

Linear and nonlinear Rossby waves in basins both with and without a thin meridional barrier /

Atherton, Juli. January 1900 (has links)
Thesis (S.M.)--Joint Program in Physical Oceanography at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution, 2002. / Includes bibliographical references (p. 119).
3

Linearized stationary planetary wave modelling with tropospheric forcing

Jones, Richard Edward. January 1980 (has links)
No description available.
4

Numerical simulation of critical layer evolution

Ritchie, C. Harold (Charles Harold) January 1978 (has links)
No description available.
5

Vertical resolution effects in a steady long wave model

Toth, Garry, 1951- January 1978 (has links)
No description available.
6

A barotropic stability study of free and forced planetary waves /

Fyfe, John January 1987 (has links)
The stability of free and forced planetary waves in a $ beta$-channel is investigated with a barotropic model. The forced waves at equilibrium result from a constant mean-zonal wind interacting with a finite-amplitude topography. / The frequencies of all infinitesimal perturbations to the equilibrium flows are determined numerically as a function of the flow parameters. The results are interpreted using a truncated spectral model and related to those of previous studies with infinite $ beta$-planes. In contrast to some earlier analytical studies we find that unstable long waves $(L sb{x}$ $>$ $L sb{y})$ exist under superresonant conditions. We also report on the existence of an interesting travelling topographic instability. / The linear instability of a weakly non-zonal flow is investigated numerically and analytically (via WKB theory). The theory reproduces the qualitative nature of the numerically-determined fastest-growing mode. / Nonlinear integrations, involving many degrees of freedom, reveal that initially-infinitesimal disturbances may grow explosively to finite-amplitude. The longer-term integrations are interpreted using a statistical mechanical model.
7

Numerical study of the nonlinear Rossby wave critical level development in a barotropic zonal flow

Béland, Michel January 1977 (has links)
No description available.
8

Normal mode global Rossby waves theory and observations /

Ahlquist, Jon Elling. January 1981 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1981. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 86-92).
9

Linearized stationary planetary wave modelling with tropospheric forcing

Jones, Richard Edward. January 1980 (has links)
No description available.
10

Numerical simulation of critical layer evolution

Ritchie, C. Harold (Charles Harold) January 1978 (has links)
No description available.

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