Fall 2026 UTIG Seminar Series: Michalea King

Fall 2026 UTIG Seminar Series: Michalea King

by Michalea King (University of Washington, Polar Science Center) · View the channel on PSI

Life & Natural Systems Earth Sciences & Geography RBKHydrology and the hydrosphereRBKCOceanography (seas and oceans)
🎙 Michalea King (University of Washington, Polar Science Center) 👥 605 📅 October 2, 2026 ⏱ 60 min 👁 84 📄 science communication 🧭 2026-10-08
Available in: English (current) Français

Keywords

mélangeSentinel-1ice velocitycalvingNISAR

Summary

This seminar by Michalea King (University of Washington) presents ongoing research on mapping the motion of mélange—the mixture of icebergs, sea ice, and ice fragments—in Greenland’s fjords using Synthetic Aperture Radar (SAR). The work extends standard ice-velocity mapping techniques, previously applied to grounded ice, to the proglacial fjord environment. Using Sentinel-1 C-band SAR imagery, which provides sub-monthly repeat coverage independent of cloud cover and sunlight, the team derives velocity maps of rigid mélange and quantifies its spatiotemporal variability around Greenland. The talk explains that only rigid, coherently moving mélange can be tracked; loosely consolidated mélange does not yield coherent displacement and is therefore not mapped. Results from Rink and Helheim glaciers show that periods of persistent rigid mélange generally coincide with glacier advance, while rapid flush-out events can precede calving, suggesting a causal link. The speaker also introduces a method to derive flow lines through the mélange to infer whether it is extending or compressing, which may help distinguish between mélange-triggered calving and glacier-driven bulldozing. A major limitation is the reliance on manual terminus traces to update the fjord domain. The talk concludes with future directions, including the use of NASA’s NISAR mission for denser SAR coverage and cross-disciplinary applications in ecology and biology.

204 words

Critical Evaluation

Value of the Information & Strength of the Argument

The presentation offers substantial informational value by detailing a novel extension of established remote-sensing techniques to a poorly mapped component of the cryosphere: fjord mélange. It clearly defines mélange, distinguishes rigid from non-rigid states, and explains why only the former can be tracked with SAR offset tracking. The argumentation is structured and logical: from method development to case studies (Rink, Helheim, Upernavik) to process interpretation. The speaker explicitly acknowledges uncertainties, such as the chicken-and-egg problem between calving and mélange flush-out, and the subjective nature of delineating rigid mélange. The use of multiple glaciers and multi-year time series strengthens the empirical basis. However, some interpretations remain preliminary and rely on visual correlation rather than statistical testing. The value lies in the methodological advance and the generation of new datasets that can be used by the broader community.

Scientific Rigor, Source Quality, Title Accuracy

The scientific rigor is high: the methods are standard in glaciology (Sentinel-1 SAR offset tracking, velocity mapping), and the speaker is transparent about limitations and ongoing work. Sources are not explicitly cited in the talk, but the description provides a link to the speaker’s personal website (michaleaking.github.io) where further work can be found. No external references or URLs are given in the description beyond that. The title accurately reflects the content, with no misleading elements. The presentation is a seminar, not a peer-reviewed publication, but it follows standard scientific communication practices. No comments were provided for analysis.

248 words

Title / Content Match

The title accurately reflects the content: the talk is precisely about mapping ice motion beyond the Greenland ice sheet margins using SAR, focusing on mélange in fjords. No discrepancy.

Quality & Reliability

8/10

The presentation is a research seminar by an established polar scientist, based on peer-reviewed-style work funded by NSF and NASA. Methods (Sentinel-1 SAR offset tracking, velocity mapping) are standard and clearly described. Limitations are acknowledged explicitly (dependence on manual terminus traces, inability to track non-rigid mélange, ambiguity in cause-effect between calving and mélange flush-out). No sensationalism, no unsupported claims. The score is not higher because the talk is a work-in-progress with preliminary results and no published paper is cited in the description.

Key Moments

Markers derived by PSI from the transcript: the creator did not define chapters.

Cited Sources

Contribution & Novelties

This work is novel in extending ice-velocity mapping techniques from grounded ice to the mélange within Greenland’s fjords, providing the first comprehensive attempt to map rigid mélange motion around Greenland. It introduces a method to derive flow lines through mélange to infer whether it is extending or compressing, which can help distinguish between mélange-triggered calving and glacier-driven bulldozing. The project also generates new datasets that are being integrated into ecological and biological studies, demonstrating cross-disciplinary value. The talk highlights the potential of NASA’s NISAR mission to improve temporal resolution for identifying rapid fjord flushing events.

Pour aller plus loin :

  • Sentinel-1 — ESA’s radar satellite mission providing the SAR data used in this study.
  • NISAR — NASA-ISRO SAR mission launched in 2025, expected to provide denser SAR coverage.
  • Ice mélange — Wikipedia article on the mixture of sea ice and icebergs in fjords.
  • Glacier velocity — Overview of glacier dynamics and mass balance.

153 words

Radar Profile

The radar profile shows high reliability and quality, with moderate technical level and information quantity. The content is specialized but accessible to an informed audience, and the speaker's transparency about limitations supports the high reliability score.

Reliability 8/10