{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/85983"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/85983","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Low-Frequency Variability in the Stratosphere","abstract":"\"We have run a dry, nonlinear, primitive equation spectral model with no externally forced variability and with a realistic time mean state, and we have observed low frequency variability (LFV) in the stratosphere with timescales on the order of hundreds of days. Time lagged correlations have revealed that this variability is linked to LFV in the emission of longwaves from the troposphere. A set of linear model experiments is performed to determine the source of the stratospheric LFV. One set of runs reveal the lowest levels of the model troposphere as the source of most of the relevant forcing. A second set of runs forced with nonlinear terms has shown that the nonlinear interaction among shortwave, high-frequency eddy thermal anomalies in the troposphere has a \"\"beating\"\" effect which emits vertically propagating low-frequency longwaves. We also see that the eddies act in such a way as to offset the effects of linear temperature advection, allowing the thermal eddies to persist for long periods.\"","abstract_html":""We have run a dry, nonlinear, primitive equation spectral model with no externally forced variability and with a realistic time mean state, and we have observed low frequency variability (LFV) in the stratosphere with timescales on the order of hundreds of days. Time lagged correlations have revealed that this variability is linked to LFV in the emission of longwaves from the troposphere. A set of linear model experiments is performed to determine the source of the stratospheric LFV. One set of runs reveal the lowest levels of the model troposphere as the source of most of the relevant forcing. A second set of runs forced with nonlinear terms has shown that the nonlinear interaction among shortwave, high-frequency eddy thermal anomalies in the troposphere has a ""beating"" effect which emits vertically propagating low-frequency longwaves. We also see that the eddies act in such a way as to offset the effects of linear temperature advection, allowing the thermal eddies to persist for long periods."","abstract_has_math":false,"creators":["Werth, David William"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Atmospheric Sciences","degree_department":null,"school":null,"contributors":["Walter Robinson"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-28T14:52:26Z","date_published":"2015-09-28T14:52:26Z","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)AAI9812806"],"render_values":[{"text":"(MiAaPQ)AAI9812806","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/85983","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Walter Robinson"]},{"key":"dc:creator","label":"Author","values":["Werth, David William"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-28T14:52:26Z","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/2142/85983","(MiAaPQ)AAI9812806"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["\"We have run a dry, nonlinear, primitive equation spectral model with no externally forced variability and with a realistic time mean state, and we have observed low frequency variability (LFV) in the stratosphere with timescales on the order of hundreds of days. Time lagged correlations have revealed that this variability is linked to LFV in the emission of longwaves from the troposphere. A set of linear model experiments is performed to determine the source of the stratospheric LFV. One set of runs reveal the lowest levels of the model troposphere as the source of most of the relevant forcing. A second set of runs forced with nonlinear terms has shown that the nonlinear interaction among shortwave, high-frequency eddy thermal anomalies in the troposphere has a \"\"beating\"\" effect which emits vertically propagating low-frequency longwaves. We also see that the eddies act in such a way as to offset the effects of linear temperature advection, allowing the thermal eddies to persist for long periods.\"","Made available in DSpace on 2015-09-28T14:52:26Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 9812806.pdf: 3983214 bytes, checksum: 9dcf0e76d2446d2cc9b0b1344ae360d7 (MD5) Previous issue date: 1997","Embargo set by: Seth Robbins for item 87264 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","166 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1997."]},{"key":"dc:title","label":"Title","values":["Low-Frequency Variability in the Stratosphere"]}]}],"canonical_facts":{"dc:contributor":["Walter Robinson"],"dc:creator":["Werth, David William"],"dc:date":["2015-09-28T14:52:26Z","10000-01-01","1997"],"dc:description":["\"We have run a dry, nonlinear, primitive equation spectral model with no externally forced variability and with a realistic time mean state, and we have observed low frequency variability (LFV) in the stratosphere with timescales on the order of hundreds of days. Time lagged correlations have revealed that this variability is linked to LFV in the emission of longwaves from the troposphere. A set of linear model experiments is performed to determine the source of the stratospheric LFV. One set of runs reveal the lowest levels of the model troposphere as the source of most of the relevant forcing. A second set of runs forced with nonlinear terms has shown that the nonlinear interaction among shortwave, high-frequency eddy thermal anomalies in the troposphere has a \"\"beating\"\" effect which emits vertically propagating low-frequency longwaves. We also see that the eddies act in such a way as to offset the effects of linear temperature advection, allowing the thermal eddies to persist for long periods.\"","Made available in DSpace on 2015-09-28T14:52:26Z (GMT). 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