Abstract
At tidewater glaciers, plume dynamics affect submarine melting, fjord circulation, and the mixing of meltwater. Models often rely on buoyant plume theory to parameterize plumes and submarine melting; however, these parameterizations are largely untested due to a dearth of near-glacier measurements. Here we present a high-resolution ocean survey by ship and remotely operated boat near the terminus of Kangerlussuup Sermia in west Greenland. These novel observations reveal the 3-D structure and transport of a near-surface plume, originating at a large undercut conduit in the glacier terminus, that is inconsistent with axisymmetric plume theory, the most common representation of plumes in ocean-glacier models. Instead, the observations suggest a wider upwelling plume—a “truncated” line plume of ∼200 m width—with higher entrainment and plume-driven melt compared to the typical axisymmetric representation. Our results highlight the importance of a subglacial outlet's geometry in controlling plume dynamics, with implications for parameterizing the exchange flow and submarine melt in glacial fjord models.
Original language | English (US) |
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Pages (from-to) | 6886-6894 |
Number of pages | 9 |
Journal | Geophysical Research Letters |
Volume | 44 |
Issue number | 13 |
DOIs | |
State | Published - Jul 16 2017 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Geophysics
- General Earth and Planetary Sciences
Keywords
- entrainment
- fjord
- glacier
- plume
- subglacial discharge
- submarine melt