{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/71980"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/71980","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Lidar and Modeling Studies of the Mesospheric Iron and Sodium Layers","abstract":"The mesospheric metals are believed to be the product of meteoric ablation. Very thin and brief layers observed in our lidar data, attributed to recently ablated meteors, are used to examine this hypothesis. The altitude distribution of these trails is compared to a model of meteoric deposition, meteor radar data, and average Fe and Na density profiles. The total meteoric influx is derived from our data and argued to be a lower limit on the actual meteoric influx.","abstract_html":"The mesospheric metals are believed to be the product of meteoric ablation. Very thin and brief layers observed in our lidar data, attributed to recently ablated meteors, are used to examine this hypothesis. The altitude distribution of these trails is compared to a model of meteoric deposition, meteor radar data, and average Fe and Na density profiles. The total meteoric influx is derived from our data and argued to be a lower limit on the actual meteoric influx.","abstract_has_math":false,"creators":["Kane, Timothy Joseph"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical Engineering","degree_department":null,"school":null,"contributors":["Gardner, C.,"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-16T22:22:59Z","date_published":"2014-12-16T22:22:59Z","updated_at":"2026-07-22T22:26:05Z","subjects":["Engineering, Electronics and Electrical"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI9305572"],"render_values":[{"text":"(UMI)AAI9305572","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/71980","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Gardner, C.,"]},{"key":"dc:creator","label":"Author","values":["Kane, Timothy Joseph"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-16T22:22:59Z","10000-01-01","1992"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical Engineering"]},{"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":["Engineering, Electronics and Electrical"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/71980","(UMI)AAI9305572"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The mesospheric metals are believed to be the product of meteoric ablation. Very thin and brief layers observed in our lidar data, attributed to recently ablated meteors, are used to examine this hypothesis. The altitude distribution of these trails is compared to a model of meteoric deposition, meteor radar data, and average Fe and Na density profiles. The total meteoric influx is derived from our data and argued to be a lower limit on the actual meteoric influx.","Sporadic layers are very dense, thin, long-duration enhancements in the mesospheric metals. Two case studies of sporadic Na (Na$\\sb{\\rm s})$ layers, which provide insight into the true nature of these puzzling phenomena, are presented here. The first, concerning data collected during the AIDA-89 campaign in Arecibo, Puerto Rico, explores the connection between Na$\\sb{\\rm s}$ layers and sporadic-E (E$\\sb{\\rm s})$ layers. Following this, several Na$\\sb{\\rm s}$ layers observed during the ALOHA-90 airborne lidar campaign over the mid-Pacific are analyzed. The results indicate that sporadic layers can extend horizontally over thousands of kilometers and can be strongly influenced by atmospheric dynamics.","Finally, a lidar and modeling study of the mesospheric Fe layer at Urbana is presented. Strong seasonal variations in the Fe layer abundance, height and width, quite different from those observed in the Na layer, are demonstrated. A simple chemical model is developed and shown to predict the Fe layer shape as well as these seasonal variations. According to our results, the Fe layer column abundance will decrease dramatically over the next century in response to predicted cooling due to global change. Numerous sporadic Fe (Fe$\\sb{\\rm s})$ layers were observed and found to have characteristics different from those for Na$\\sb{\\rm s}$ layers. Our model suggests that Fe$\\sb{\\rm s}$ layers form by a two-step neutralization of Fe$\\sp+$ brought on by excess electrons found in sporadic-E layers.","Made available in DSpace on 2014-12-16T22:22:59Z (GMT). No. of bitstreams: 1 9305572.pdf: 3919595 bytes, checksum: 8f74d6569e4174bb9e96d41950104bb8 (MD5) Previous issue date: 1992","Embargo set by: Seth Robbins for item 72146 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","114 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1992."]},{"key":"dc:title","label":"Title","values":["Lidar and Modeling Studies of the Mesospheric Iron and Sodium Layers"]}]}],"canonical_facts":{"dc:contributor":["Gardner, C.,"],"dc:creator":["Kane, Timothy Joseph"],"dc:date":["2014-12-16T22:22:59Z","10000-01-01","1992"],"dc:description":["The mesospheric metals are believed to be the product of meteoric ablation. Very thin and brief layers observed in our lidar data, attributed to recently ablated meteors, are used to examine this hypothesis. The altitude distribution of these trails is compared to a model of meteoric deposition, meteor radar data, and average Fe and Na density profiles. The total meteoric influx is derived from our data and argued to be a lower limit on the actual meteoric influx.","Sporadic layers are very dense, thin, long-duration enhancements in the mesospheric metals. Two case studies of sporadic Na (Na$\\sb{\\rm s})$ layers, which provide insight into the true nature of these puzzling phenomena, are presented here. The first, concerning data collected during the AIDA-89 campaign in Arecibo, Puerto Rico, explores the connection between Na$\\sb{\\rm s}$ layers and sporadic-E (E$\\sb{\\rm s})$ layers. Following this, several Na$\\sb{\\rm s}$ layers observed during the ALOHA-90 airborne lidar campaign over the mid-Pacific are analyzed. The results indicate that sporadic layers can extend horizontally over thousands of kilometers and can be strongly influenced by atmospheric dynamics.","Finally, a lidar and modeling study of the mesospheric Fe layer at Urbana is presented. Strong seasonal variations in the Fe layer abundance, height and width, quite different from those observed in the Na layer, are demonstrated. A simple chemical model is developed and shown to predict the Fe layer shape as well as these seasonal variations. According to our results, the Fe layer column abundance will decrease dramatically over the next century in response to predicted cooling due to global change. Numerous sporadic Fe (Fe$\\sb{\\rm s})$ layers were observed and found to have characteristics different from those for Na$\\sb{\\rm s}$ layers. Our model suggests that Fe$\\sb{\\rm s}$ layers form by a two-step neutralization of Fe$\\sp+$ brought on by excess electrons found in sporadic-E layers.","Made available in DSpace on 2014-12-16T22:22:59Z (GMT). No. of bitstreams: 1 9305572.pdf: 3919595 bytes, checksum: 8f74d6569e4174bb9e96d41950104bb8 (MD5) Previous issue date: 1992","Embargo set by: Seth Robbins for item 72146 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","114 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1992."],"dc:identifier":["http://hdl.handle.net/2142/71980","(UMI)AAI9305572"],"dc:subject":["Engineering, Electronics and Electrical"],"dc:title":["Lidar and Modeling Studies of the Mesospheric Iron and Sodium Layers"],"dc:type":["text"],"thesis:degree_discipline":["Electrical Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:05Z"}