TermPicks: a century of Greenland glacier terminus data for use in scientific and machine learning applications

Abstract

Abstract. Marine-terminating outlet glacier terminus traces, mapped from satellite and aerial imagery, have been used extensively in understanding how outlet glaciers adjust to climate change variability over a range of timescales. Numerous studies have digitized termini manually, but this process is labor intensive, and no consistent approach exists. A lack of coordination leads to duplication of efforts, particularly for Greenland, which is a major scientific research focus. At the same time, machine learning techniques are rapidly making progress in their ability to automate accurate extraction of glacier termini, with promising developments across a number of optical and synthetic aperture radar (SAR) satellite sensors. These techniques rely on high-quality, manually digitized terminus traces to be used as training data for robust automatic traces. Here we present a database of manually digitized terminus traces for machine learning and scientific applications. These data have been collected, cleaned, assigned with appropriate metadata including image scenes, and compiled so they can be easily accessed by scientists. The TermPicks data set includes 39 060 individual terminus traces for 278 glaciers with a mean of 136 ± 190 and median of 93 of traces per glacier. Across all glaciers, 32 567 dates have been digitized, of which 4467 have traces from more than one author, and there is a duplication rate of 17 %. We find a median error of ∼ 100 m among manually traced termini. Most traces are obtained after 1999, when Landsat 7 was launched. We also provide an overview of an updated version of the Google Earth Engine Digitization Tool (GEEDiT), which has been developed specifically for future manual picking of the Greenland Ice Sheet.

Seasonal Flow Types of Glaciers in Sermilik Fjord, Greenland, Over 2016–2021

“…This glacier, located at 66.48°N, 36.72°W, takes various names: most commonly Midgard Glacier (Moon et al, 2014;Mouginot et al, 2019), but also Franche Comté Glacier (Bjørk et al, 2015;Goliber et al, 2022;Vijay et al, 2019) or Midgard North (Walsh et al, 2012;Williams, 2021). This glacier extended 10 km farther down its fjord as recently as 2002, but since has retreated rapidly and split into two glaciers around 2012 (Korsgaard, 2021).…”

“…This glacier separated from Midgard Glacier in 2012 (Korsgaard, 2021). It is significantly smaller and less well studied than the other glaciers in Sermilik Fjord, and many databases omit its name (Bjørk et al, 2015;Mouginot et al, 2019) or refer to it as Midgard South (Williams, 2021) or Midgard Glacier (Goliber et al, 2022;Vijay et al, 2019;Walsh et al, 2012), as it lies directly upfjord of the reach that Midgard used to occupy before its split. The northwestern tributary is significantly larger and we term it Midgard Glacier (Section 3.3).…”

IceLines – A new data set of Antarctic ice shelf front positions

“…Nevertheless, manual front delineation is a very challenging task and underlies a high degree of subjectivity. Having several experts delineating the same front will always generate different results 12,30,33,34 . Hence, the automated front position is not necessarily wrong if it does not align with the manual reference.…”

Ocean‐Forcing and Glacier‐Specific Factors Drive Differing Glacier Response Across the 69°N Boundary, East Greenland

“…Much of the Greenland Ice Sheet underwent widespread and rapid outlet glacier retreat in the 2000 s (e.g., Goliber et al., 2022; King et al., 2018), but glaciers along Greenland's east coast showed markedly different behavior during this time (e.g., Carr et al., 2017; Seale et al., 2011; Walsh et al., 2012). Specifically, Seale et al.…”

“…Much of the Greenland Ice Sheet underwent widespread and rapid outlet glacier retreat in the 2000 s (e.g., Goliber et al, 2022;King et al, 2018), but glaciers along Greenland's east coast showed markedly different behavior during this time (e.g., Carr et al, 2017;Seale et al, 2011;Walsh et al, 2012). Specifically, Seale et al (2011) examined patterns of frontal retreat for 32 glaciers along the east Greenland coast between 2000 and 2009 and found a distinct contrast between glaciers located south of 69°N compared to those to the north.…”