{"650322":{"#nid":"650322","#data":{"type":"event","title":"Methane, Monsoons, and Milankovitch Modulation of Millennial-scale Climate Variability","body":[{"value":"\u003Ch4\u003E\u003Cstrong\u003EThe School of Earth and Atmospheric Sciences Presents Dr.\u0026nbsp;Kaustubh Thirumalai, University of Arizona\u003C\/strong\u003E\u003C\/h4\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EMethane, Monsoons, and Milankovitch Modulation of Millennial-scale Climate Variability\u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003EEarth\u0026#39;s orbital geometry exerts a profound influence on climate by regulating changes in\u0026nbsp;incoming solar radiation. Superimposed on orbitally paced climate change,\u0026nbsp;Pleistocene records reveal\u0026nbsp;substantial millennial-scale variability characterized by abrupt changes and rapid swings. However, the\u0026nbsp;extent to which orbital forcing\u0026nbsp;modulates the amplitude and timing of these millennial variations is\u0026nbsp;unclear.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EHere I will present results where we isolate the magnitude of millennial-scale variability (MMV) in two well-dated\u0026nbsp;records,\u0026nbsp;both linked to precession cycles (19,000- and 23,000-year periodicity): composite Chinese speleothem \u0026delta;\u0026sup1;\u2078O,\u0026nbsp;commonly interpreted as a proxy for Asian\u0026nbsp;monsoon intensity, and atmospheric methane. At the\u0026nbsp;millennial timescale (1,000\u0026ndash;10,000 years), we find a fundamental decoupling wherein precession directly\u0026nbsp;modulates the MMV of methane but not that of speleothem \u0026delta;\u0026sup1;\u2078O, which is shown to be strikingly similar to\u0026nbsp;the MMV of Antarctic ice core\u0026nbsp;\u0026delta;D. One explanation is\u0026nbsp;that the MMV of methane responds to changes in\u0026nbsp;midlatitude to high-latitude insolation, whereas speleothem \u0026delta;\u0026sup1;\u2078O\u0026nbsp;is modulated by internal climate\u0026nbsp;feedbacks.\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"A seminar by Dr. Kaustubh Thirumalai, Earth and Atmospheric Sciences"}],"uid":"34458","created_gmt":"2021-08-31 20:01:56","changed_gmt":"2021-11-18 15:31:18","author":"nlawson3","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2021-11-18T11:00:00-05:00","event_time_end":"2021-11-18T12:00:00-05:00","event_time_end_last":"2021-11-18T12:00:00-05:00","gmt_time_start":"2021-11-18 16:00:00","gmt_time_end":"2021-11-18 17:00:00","gmt_time_end_last":"2021-11-18 17:00:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"hg_media":{"650320":{"id":"650320","type":"image","title":"Kaustubh Thirumalai ","body":null,"created":"1630439904","gmt_created":"2021-08-31 19:58:24","changed":"1630439904","gmt_changed":"2021-08-31 19:58:24","alt":"","file":{"fid":"246810","name":"Kaustubh Thirumalai.jpg","image_path":"\/sites\/default\/files\/images\/Kaustubh%20Thirumalai.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/Kaustubh%20Thirumalai.jpg","mime":"image\/jpeg","size":11642,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/Kaustubh%20Thirumalai.jpg?itok=JhqynzSs"}}},"media_ids":["650320"],"groups":[{"id":"364801","name":"School of Earth and Atmospheric Sciences (EAS)"}],"categories":[],"keywords":[{"id":"175623","name":"EAS Seminar"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1795","name":"Seminar\/Lecture\/Colloquium"}],"invited_audience":[{"id":"78761","name":"Faculty\/Staff"},{"id":"177814","name":"Postdoc"},{"id":"174045","name":"Graduate students"},{"id":"78751","name":"Undergraduate students"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EDr. Jean Lynch-Stieglitz\u003C\/p\u003E\r\n","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}