{"685091":{"#nid":"685091","#data":{"type":"event","title":"PhD Defense by Ziad Rashed","body":[{"value":"\u003Cp\u003EIn partial fulfillment of the requirements for the degree of\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EDoctor of Philosophy in Ocean Science \u0026amp; Engineering\u003C\/p\u003E\u003Cp\u003EIn the\u003C\/p\u003E\u003Cp\u003ESchool of \u003Cstrong\u003EEarth and Atmospheric Sciences\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EZiad Rashed\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EWill defend his dissertation\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EThe Dynamic Interplay of Ice M\u00e9lange and Calving Glacier Interfaces\u003C\/strong\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EOctober 2nd, 2025\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;1 PM EST\u003C\/p\u003E\u003Cp\u003EFord ES\u0026amp;T 3235 \u201cThe Ocean Room\u201d\u003C\/p\u003E\u003Cp\u003E\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002\u2002https:\/\/gatech.zoom.us\/j\/94341539689 \u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003Cstrong\u003EThesis Advisor:\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EAlexander Robel, Ph.D.\u003C\/p\u003E\u003Cp\u003ESchool of Earth and Atmospheric Sciences\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EGeorgia Institute of Technology\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECommittee Members:\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EWinnie Chu, Ph.D.\u003C\/p\u003E\u003Cp\u003ESchool of Earth and Atmospheric Sciences\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EGeorgia Institute of Technology\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EMark Hay, Ph.D.\u003C\/p\u003E\u003Cp\u003ESchool of Biological Sciences\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EGeorgia Institute of Technology\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EYuhang Hu, Ph.D.\u003C\/p\u003E\u003Cp\u003ESchool of Mechanical Engineering\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EGeorgia Institute of Technology\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EJason Amundson, Ph.D.\u003C\/p\u003E\u003Cp\u003EDepartment of Natural Sciences\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EUniversity of Alaska Southeast\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EABSTRACT:\u003C\/p\u003E\u003Cp\u003EFuture sea level projections are subject to uncertainties in ice sheet processes, including slow variations in ice flow speed and fast variations in melting and calving, which are driven by increasing oceanic and atmospheric temperatures. Recent studies suggest that the contribution of ice sheets to sea level rise over coming centuries is likely to be higher than previously projected due to the potential for rapid ice fracture and iceberg calving from the edge of ice sheets. This thesis seeks to address this issue by investigating the dynamic feedbacks between glaciers and the icebergs they generate through calving, with a particular emphasis on the role of ice m\u00e9lange. Ice m\u00e9lange is a slushy amalgamation of icebergs and sea ice, which is thought to function like an ice shelf by slowing glacier flow from the ice sheet interior and preventing fracturing and calving of new icebergs. Although m\u00e9lange currently persists seasonally or throughout the year at numerous glaciers in Greenland and Antarctica, its importance may rise in conjunction with escalated calving rates. The principal aim of this research is to resolve open scientific questions concerning the role of ice m\u00e9lange in the mechanics of iceberg calving and the retreat of glaciers.\u003C\/p\u003E\u003Cp\u003EIn the first project described in this thesis, I employ the Helsinki Discrete Element Model (HiDEM) to simulate calving-m\u00e9lange feedbacks down to spatial scales of meters and temporal scales of seconds. This high-fidelity model facilitates understanding of how m\u00e9lange buttressing influences the stress state at the glacier terminus and enables the identification of variations in calving rates and styles. I analyze bulk calving statistics from this model, including calving event size and recurrence time, which provide insights into short time-scale events that regulate glacier calving. Though such a high-fidelity model is useful for conducting process studies of glacier calving, its high computational expense prevent its use for projecting ice sheet behavior over climate-relevant time scales of decades and longer. Consequently, I conduct a case study of Sermeq Kujalleq, the fastest flowing glacier in Greenland, using the Ice-Sheet and Sea-Level System Model (ISSM) to discern the relative impacts of submarine melting and a weakened ice m\u00e9lange on the glacier\u0027s recent retreat. By adjusting the sensitivity of melt rates and a calving stress threshold parameter, I conclude that Sermeq Kujalleq\u0027s ocean-induced retreat starting in the late 1990\u0027s was predominantly driven by a weakened ice m\u00e9lange following an influx of warm ocean waters. However, parameterized representation of m\u00e9lange variations hinder the ability of such models to project future coupled evolution of m\u00e9lange and glacier calving. To remedy this shortcoming of current models, I develop a two-dimensional continuum model of ice m\u00e9lange, GLACIOME2D, which integrates the granular physics of m\u00e9lange and its mechanical interactions with the ice-ocean environment over climate-relevant timescales. Collectively, my findings integrate insights from high-fidelity discrete element modeling with efficient continuum modeling to provide advances in long-term projections of ice sheet mass loss and contributions to sea level rise.\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EThe Dynamic Interplay of Ice M\u00e9lange and Calving Glacier Interfaces\u0026nbsp;\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"The Dynamic Interplay of Ice M\u00e9lange and Calving Glacier Interfaces "}],"uid":"27707","created_gmt":"2025-09-18 18:36:33","changed_gmt":"2025-09-18 18:37:08","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2025-10-02T13:00:00-04:00","event_time_end":"2025-10-02T15:00:00-04:00","event_time_end_last":"2025-10-02T15:00:00-04:00","gmt_time_start":"2025-10-02 17:00:00","gmt_time_end":"2025-10-02 19:00:00","gmt_time_end_last":"2025-10-02 19:00:00","rrule":null,"timezone":"America\/New_York"},"location":"Ford ES\u0026T 3235 \u201cThe Ocean Room\u201d","extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"100811","name":"Phd Defense"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}