Glacier Modeling Lab presentations at AGU 2021,q_auto/v1638741830/agu-fm2021/84-88-ab-27-6b-d5-88-4b-58-2a-a9-93-fc-ba-27-2c/image/helheim_als_scalebymag_trendrm_23_minfrac0.90_pceof1_15-oct-2013-15-may-2021_05-dec-2021_qz9uqy.jpg
Figure from Kristin’s eLightning poster about Helheim Glacier and other glaciers feeding Sermilik Fjord. The leading principal component (blue data on bottom panel) correlates with both the terminus position (p=0.003, red data) and a seasonal cycle with maximum in mid-July (p=0.05, blue dashed line) that is consistent with runoff-control. The terminus position itself correlates to this annual cycle (R=-0.11, p=0.1). Examining p-values and considering some commonality of the forcings, we classify Helheim Glacier as terminus-controlled over 2014-2021.

This agrees with previous classifications of Helheim Glacier as usually terminus-controlled (2009, 2010, 2015, 2016, 2017) [1,2,3] and sometimes runoff-controlled (2013) [1].  It agrees less with a study that found Helheim was runoff-controlled over 2009-2017 [7].
Map of Sermilik Fjord study area
Figure from Kristin’s eLightning poster. Sermilik Fjord, eastern Greenland, contains four major outlet glaciers. Helheim Glacier (westernmost) is the largest. The base map is a mosaic of Sentinel-2 images from summer 2019, by MacGregor et al. (2020). The wintertime terminus positions are from PROMICE.

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