Spatiotemporal evolution of subaerial ice cliff heights at marine-terminating outlet glaciers in Northwestern Greenland

• DOI: 10.5194/egusphere-egu24-11023
• Publication Date: 2024-03-08T20:55:33Z
• Authors: Emma Carr; Rachel Carr; Chris Stokes; Emily Hill; Hilmar Gudmundsson; Neil Ross
• Keywords: Subaerial; Cliff; Ice caps

Many tidewater glaciers in Greenland terminate near-vertical ice cliffs from which icebergs calve. Marine Ice Cliff Instability (MICI) is the hypothesis that above a subaerial cliff height limit, tensile or shear stresses at glacier terminus surpass yield strength, causing catastrophic failure and self-sustaining frontal retreat as sequentially taller are exposed. Previous modelling studies have proposed this threshold least 100 m, with estimated thresholds including m 110 for damaged ice, up to 540 when treated undamaged. However, modern-day observations test MICI limited because few marine-terminating outlet without buttressing shelf known greater than high. Here, we expand of heights ten northwest using 2 spatial resolution Arctic DEM strips. Our results identify three currently exposed approaching exceeding stability MICI. During two years between 2016 2021, Nuussuup Sermia (NuS), Nunnatakassaap (NkS) Sermeq North (SqN) exceeded m. Despite being these postulated thought conducive failure, SqN underwent relatively net (0.25 km), NuS NkS exhibited distinct seasonal cycles advance (up 0.92 km) March June/July each year prior disintegration removal proglacial mélange. Consequently, none identified potentially susceptible rapid, unforced retreat. We hypothesise processes were mitigated by dynamic thinning lowering surface elevation immediately up-glacier so progressively not after Further research required monitor model evolution better understand potential unstable West Antarctica due