{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/85980"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/85980","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Barotropic Model Simulations of Low-Frequency Variability","abstract":"Unforced, subcritical nonlinear simulations fail to produce meaningful variability, indicating that forcing is necessary in maintaining the low-frequency variability in the barotropic system under subcritical condition. Stochastically forced experiments are conducted using spatially homogeneous forcing. In the weakly subcritical cases, the model produces spatially and temporally coherent variability, with the first two EOFs of the perturbation field resembling the phase quadrature of the leading normal mode. In this case, the normal mode and retrograde wave structures emerge without normal mode instability. In the strongly subcritical cases, the stochastically forced solutions generally exhibit poor coherence. A stochastically-driven scenario works only in the weakly subcritical regime. The characteristics of the optimal perturbations in the barotropic system are examined. A more general type of spectrally-constrained optimal perturbation is discussed.","abstract_html":"Unforced, subcritical nonlinear simulations fail to produce meaningful variability, indicating that forcing is necessary in maintaining the low-frequency variability in the barotropic system under subcritical condition. Stochastically forced experiments are conducted using spatially homogeneous forcing. In the weakly subcritical cases, the model produces spatially and temporally coherent variability, with the first two EOFs of the perturbation field resembling the phase quadrature of the leading normal mode. In this case, the normal mode and retrograde wave structures emerge without normal mode instability. In the strongly subcritical cases, the stochastically forced solutions generally exhibit poor coherence. A stochastically-driven scenario works only in the weakly subcritical regime. The characteristics of the optimal perturbations in the barotropic system are examined. A more general type of spectrally-constrained optimal perturbation is discussed.","abstract_has_math":false,"creators":["Huang, Huei-Ping"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Atmospheric Sciences","degree_department":null,"school":null,"contributors":["Robinson, Walter A."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-28T14:52:25Z","date_published":"2015-09-28T14:52:25Z","updated_at":"2026-07-22T22:26:26Z","subjects":["Physics, Atmospheric Science"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI9737135"],"render_values":[{"text":"(MiAaPQ)AAI9737135","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/85980","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Robinson, Walter A."]},{"key":"dc:creator","label":"Author","values":["Huang, Huei-Ping"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-28T14:52:25Z","10000-01-01","1997"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Atmospheric Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Physics, Atmospheric Science"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/85980","(MiAaPQ)AAI9737135"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Unforced, subcritical nonlinear simulations fail to produce meaningful variability, indicating that forcing is necessary in maintaining the low-frequency variability in the barotropic system under subcritical condition. Stochastically forced experiments are conducted using spatially homogeneous forcing. In the weakly subcritical cases, the model produces spatially and temporally coherent variability, with the first two EOFs of the perturbation field resembling the phase quadrature of the leading normal mode. In this case, the normal mode and retrograde wave structures emerge without normal mode instability. In the strongly subcritical cases, the stochastically forced solutions generally exhibit poor coherence. A stochastically-driven scenario works only in the weakly subcritical regime. The characteristics of the optimal perturbations in the barotropic system are examined. A more general type of spectrally-constrained optimal perturbation is discussed.","Made available in DSpace on 2015-09-28T14:52:25Z (GMT). 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Stochastically forced experiments are conducted using spatially homogeneous forcing. In the weakly subcritical cases, the model produces spatially and temporally coherent variability, with the first two EOFs of the perturbation field resembling the phase quadrature of the leading normal mode. In this case, the normal mode and retrograde wave structures emerge without normal mode instability. In the strongly subcritical cases, the stochastically forced solutions generally exhibit poor coherence. A stochastically-driven scenario works only in the weakly subcritical regime. The characteristics of the optimal perturbations in the barotropic system are examined. A more general type of spectrally-constrained optimal perturbation is discussed.","Made available in DSpace on 2015-09-28T14:52:25Z (GMT). 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