{"638020":{"#nid":"638020","#data":{"type":"event","title":"Physical Models for Moulins, Conduits to the Subglacial World","body":[{"value":"\u003Ch4\u003E\u003Cstrong\u003EThe School of Earth and Atmospheric Sciences Presents Dr. Kristin Poinar, University of Buffalo\u003C\/strong\u003E\u003C\/h4\u003E\r\n\r\n\u003Cp\u003EPhysical Models for Moulins, Conduits to the Subglacial World\u003C\/p\u003E\r\n\r\n\u003Cp\u003EGlacier hydrology is a crucial factor in short-term (daily) and long-term (millennial) calculations of glacier mass loss into the ocean.\u0026nbsp; This is because meltwater influences the flow of glacier ice if it reaches the bed.\u0026nbsp;\u0026nbsp; On the Greenland Ice Sheet, meltwater can run over bare ice, coalesce into streams, and pool into lakes on top of the ice.\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EFrom there, the water is often -- but not always -- directed into moulins, near-vertical shafts that connect to the bed of the ice sheet hundreds of meters below.\u0026nbsp; Moulins drain large catchments of surface meltwater -- typically 10-30 km2, or ten Georgia Tech campuses -- and thus have a controlling influence on basal hydrology.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EI am developing two models centered around moulins. (1) The Moulin Shape (MouSh) model predicts the radial expansion and contraction of a moulin connected to a subglacial channel and fed by hourly varying meltwater inputs.\u0026nbsp; We find that the moulin size and shape changes daily by some 20% as it accommodates changing meltwater fluxes.\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E(2) The Fracture Sites\u0026nbsp; model (FraSM) predicts the likelihood of moulin initiation in space and time.\u0026nbsp; We find that moulin formation sites are strongly tied to drainages of neighboring supraglacial lakes, and that new moulins can form ~3-5 km upstream of a draining lake.\u0026nbsp; A new, upstream moulin could then drain an upstream lake, potentially inciting a chain reaction of lake drainage \/ moulin formation that steps its way upstream toward the vulnerable interior of the ice sheet, where changes to basal hydrology could significantly speed ice flow.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EUltimately, the moulin models connect climate, in the form of surface meltwater, to sea-level rise, via basal hydrology and ice flow.\u0026nbsp; As Greenland\u0026#39;s climate changes, we need to be able to predict the sea-level rise that is coming as a consequence.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"A seminar by Dr. Kristin Poinar, Earth and Atmospheric Sciences"}],"uid":"34458","created_gmt":"2020-08-18 14:12:42","changed_gmt":"2020-08-31 19:31:30","author":"nlawson3","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2020-09-03T12:00:00-04:00","event_time_end":"2020-09-03T13:00:00-04:00","event_time_end_last":"2020-09-03T13:00:00-04:00","gmt_time_start":"2020-09-03 16:00:00","gmt_time_end":"2020-09-03 17:00:00","gmt_time_end_last":"2020-09-03 17:00:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"hg_media":{"638016":{"id":"638016","type":"image","title":"Kristin Poinar","body":null,"created":"1597759073","gmt_created":"2020-08-18 13:57:53","changed":"1597759073","gmt_changed":"2020-08-18 13:57:53","alt":"","file":{"fid":"242659","name":"K. Poinar.jpg","image_path":"\/sites\/default\/files\/images\/K.%20Poinar.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/K.%20Poinar.jpg","mime":"image\/jpeg","size":13978,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/K.%20Poinar.jpg?itok=9Xpyt8Qw"}}},"media_ids":["638016"],"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":"1788","name":"Other\/Miscellaneous"}],"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. Winnie Chu\u003C\/p\u003E\r\n","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}