skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Widespread Moulin Formation During Supraglacial Lake Drainages in Greenland

Abstract

Moulins permit access of surface meltwater to the glacier bed, causing basal lubrication and ice speedup in the ablation zone of western Greenland during summer. In spite of the substantial impact of moulins on ice dynamics, the conditions under which they form are poorly understood. We assimilate a time series of ice surface velocity from a network of eleven Global Positioning System receivers into an ice sheet model to estimate ice sheet stresses during winter, spring, and summer in a ~30 × 10 km region. Surface-parallel von Mises stress increases slightly during spring speedup and early summer, sufficient to allow formation of 16% of moulins mapped in the study area. Conversely, 63% of moulins experience stresses over the tensile strength of ice during a short (hours) supraglacial lake drainage event. Lake drainages appear to control moulin density, which is itself a control on subglacial drainage efficiency and summer ice velocities.

Authors:
ORCiD logo [1];  [2]; ORCiD logo [3]; ORCiD logo [1];  [4]; ORCiD logo [5]; ORCiD logo [6]; ORCiD logo [7]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Center for Computing Research
  3. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States). Global Modeling and Assimilation Office
  4. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States). Cryosphereic Sciences Lab.
  5. Univ. of Montana, Missoula, MT (United States). Dept. of Computer Science
  6. Univ. of Texas, Austin, TX (United States). Inst. for Geophysics, Dept. of Geological Sciences
  7. Univ. of Zurich (Switzerland). Dept. of Geography
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF); National Aeronautics and Space Administration (NASA)
OSTI Identifier:
1417225
Report Number(s):
LA-UR-17-28283
Journal ID: ISSN 0094-8276
Grant/Contract Number:
AC52-06NA25396; NA-0003525; 20160608ECR
Resource Type:
Journal Article: Published Article
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Name: Geophysical Research Letters; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; Earth Sciences; Mathematics

Citation Formats

Hoffman, Matthew J., Perego, Mauro, Andrews, Lauren C., Price, Stephen F., Neumann, Thomas A., Johnson, Jesse V., Catania, Ginny, and Lüthi, Martin P.. Widespread Moulin Formation During Supraglacial Lake Drainages in Greenland. United States: N. p., 2018. Web. doi:10.1002/2017GL075659.
Hoffman, Matthew J., Perego, Mauro, Andrews, Lauren C., Price, Stephen F., Neumann, Thomas A., Johnson, Jesse V., Catania, Ginny, & Lüthi, Martin P.. Widespread Moulin Formation During Supraglacial Lake Drainages in Greenland. United States. doi:10.1002/2017GL075659.
Hoffman, Matthew J., Perego, Mauro, Andrews, Lauren C., Price, Stephen F., Neumann, Thomas A., Johnson, Jesse V., Catania, Ginny, and Lüthi, Martin P.. 2018. "Widespread Moulin Formation During Supraglacial Lake Drainages in Greenland". United States. doi:10.1002/2017GL075659.
@article{osti_1417225,
title = {Widespread Moulin Formation During Supraglacial Lake Drainages in Greenland},
author = {Hoffman, Matthew J. and Perego, Mauro and Andrews, Lauren C. and Price, Stephen F. and Neumann, Thomas A. and Johnson, Jesse V. and Catania, Ginny and Lüthi, Martin P.},
abstractNote = {Moulins permit access of surface meltwater to the glacier bed, causing basal lubrication and ice speedup in the ablation zone of western Greenland during summer. In spite of the substantial impact of moulins on ice dynamics, the conditions under which they form are poorly understood. We assimilate a time series of ice surface velocity from a network of eleven Global Positioning System receivers into an ice sheet model to estimate ice sheet stresses during winter, spring, and summer in a ~30 × 10 km region. Surface-parallel von Mises stress increases slightly during spring speedup and early summer, sufficient to allow formation of 16% of moulins mapped in the study area. Conversely, 63% of moulins experience stresses over the tensile strength of ice during a short (hours) supraglacial lake drainage event. Lake drainages appear to control moulin density, which is itself a control on subglacial drainage efficiency and summer ice velocities.},
doi = {10.1002/2017GL075659},
journal = {Geophysical Research Letters},
number = ,
volume = ,
place = {United States},
year = 2018,
month = 1
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1002/2017GL075659

Save / Share:
  • Moulins permit access of surface meltwater to the glacier bed, causing basal lubrication and ice speedup in the ablation zone of western Greenland during summer. In spite of the substantial impact of moulins on ice dynamics, the conditions under which they form are poorly understood. We assimilate a time series of ice surface velocity from a network of eleven Global Positioning System receivers into an ice sheet model to estimate ice sheet stresses during winter, spring, and summer in a ~30 × 10 km region. Surface-parallel von Mises stress increases slightly during spring speedup and early summer, sufficient to allowmore » formation of 16% of moulins mapped in the study area. Conversely, 63% of moulins experience stresses over the tensile strength of ice during a short (hours) supraglacial lake drainage event. Lake drainages appear to control moulin density, which is itself a control on subglacial drainage efficiency and summer ice velocities.« less
  • During Rhaetian-Sinemurian time a large wave- and storm-dominated lake was situated in the Jameson Land basin, East Greenland. Lake deposits consist of alternating black unfossiliferous mudstones and sheet sandstones. Anoxic conditions dominated at the lake bottom during deposition of the muds, and the water column was probably stratified. The sandstones were deposited by progradation of wave- and storm-dominated deltas in a water depth of less than 15 m. Sequence-stratigraphic interpretation suggests that the mudstones were deposited in periods of rising and very high stands of lake level, whereas progradation of the deltaic sheet sandstones took place during forced regressions causedmore » by significant falls. The lake thus underwent a large number of fairly high amplitude changes in level, probably caused by climatic fluctuations. The high-order cycles can be grouped into several long-period cycles that show the same number of major fluctuations as published eustatic sea-level curves. This similarity suggests a causal link between eustasy and long-period variations in the lake. The Kap Stewart Formation represents one of the few ancient examples of a large wave- and storm-dominated lake, and it is probably the first documented case of abundant well-developed lacustrine forced regressions.« less
  • Hydrographic observations and measurements of the concentrations of chlorofluorocarbons (CFCs) have suggested that the formation of Greenland Sea Deep Water (GSDW) slowed down considerably during the 1980s. Such a decrease is related to weakened convection in the Greenland Sea and thus could have significant impact on the properties of the waters flowing over the Scotland-Iceland-Greenlad ridge system into the deep Atlantic. Study of the variability of GSDW formation is relevant for understanding the impact of the circulation in the European Polar seas on regional and global deep water characteristics. New long-term multitracer observations from the Greenland Sea show that GSDWmore » formation indeed was greatly reduced during the 1980s. A box model of deepwater formation and exchange in the European Polar seas tuned by the tracer data indicates that the reduction rate of GSDW formation was about 80% and that the start date of the reduction was between 1978 and 1982. 24 refs., 4 figs.« less
  • We present high-resolution observations of the 880 μm (rest-frame FIR) continuum emission in the z = 4.05 submillimeter galaxy GN20 from the IRAM Plateau de Bure Interferometer (PdBI). These data resolve the obscured star formation (SF) in this unlensed galaxy on scales of 0.''3 × 0.''2 (∼2.1 × 1.3 kpc). The observations reveal a bright (16 ± 1 mJy) dusty starburst centered on the cold molecular gas reservoir and showing a bar-like extension along the major axis. The striking anti-correlation with the Hubble Space Telescope/Wide Field Camera 3 imaging suggests that the copious dust surrounding the starburst heavily obscures the rest-frame UV/optical emission. A comparison with 1.2 mm PdBI continuummore » data reveals no evidence for variations in the dust properties across the source within the uncertainties, consistent with extended SF, and the peak star formation rate surface density (119 ± 8 M {sub ☉} yr{sup –1} kpc{sup –2}) implies that the SF in GN20 remains sub-Eddington on scales down to 3 kpc{sup 2}. We find that the SF efficiency (SFE) is highest in the central regions of GN20, leading to a resolved SF law with a power-law slope of Σ{sub SFR} ∼ Σ{sub H{sub 2}{sup 2.1±1.0}}, and that GN20 lies above the sequence of normal star-forming disks, implying that the dispersion in the SF law is not due solely to morphology or choice of conversion factor. These data extend previous evidence for a fixed SFE per free-fall time to include the star-forming medium on ∼kiloparsec scales in a galaxy 12 Gyr ago.« less