Seasonal changes of mélange thickness coincide with Greenland calving dynamics.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39794336.
- Also identified by DOI 10.1038/s41467-024-55241-7 and PMC identifier 11724111.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Iceberg calving is a major contributor to Greenland's ice mass loss. Ice mélange, tightly packed sea ice and icebergs, has been hypothesized to buttress the calving fronts. However, quantifying the mélange buttressing force from field observations remains a challenge. Here we show that such quantification can be achieved with a single field measurement: thickness of mélange at the glacier terminus. We develop a three-dimensional discrete element model of mélange along with a simple analytical model to quantify the mélange buttressing using mélange thickness data from ArcticDEM over 32 Greenland glacier termini. We observed a strong seasonality in mélange thickness: thin mélange (averaged thickness <math xmlns="http://www.w3.org/1998/Math/MathML"><mn>3</mn> <msubsup><mrow><mn>4</mn></mrow> <mrow><mo>-</mo> <mn>15</mn></mrow> <mrow><mo>+</mo> <mn>17</mn></mrow> </msubsup> </math> m) in summertime when terminus retreats, and thick mélange (averaged thickness <math xmlns="http://www.w3.org/1998/Math/MathML"><mn>11</mn> <msubsup><mrow><mn>9</mn></mrow> <mrow><mo>-</mo> <mn>37</mn></mrow> <mrow><mo>+</mo> <mn>31</mn></mrow> </msubsup> </math> m) in wintertime when terminus advances. The observed seasonal changes of mélange thickness strongly coincide with observed Greenland calving dynamics and the modeled buttressing effects.