Abstract
ABSTRACTOutlet glaciers undergo rapid spatial and temporal changes in flow velocity during calving events. Observing such changes requires both high temporal and high spatial resolution methods, something now possible with terrestrial radar interferometry. While a single such radar provides line-of-sight velocity, two radars define both components of the horizontal flow field. To assess the feasibility of obtaining the two-dimensional (2-D) flow field, we deployed two terrestrial radar interferometers at Jakobshavn Isbrae, a major outlet glacier on Greenland's west coast, in the summer of 2012. Here, we develop and demonstrate a method to combine the line-of-sight velocity data from two synchronized radars to produce a 2-D velocity field from a single (3 min) interferogram. Results are compared with the more traditional feature-tracking data obtained from the same radar, averaged over a longer period. We demonstrate the potential and limitations of this new dual-radar approach for obtaining high spatial and temporal resolution 2-D velocity fields at outlet glaciers.
Highlights
Velocity fields of tidewater glaciers are sensitive indicators of the various driving and resisting forces acting upon them (e.g. Howat and others, 2008)
We demonstrate the potential and limitations of this new dual-radar approach for obtaining high spatial and temporal resolution 2-D velocity fields at outlet glaciers
Most of the ice around the study area flows to the northwest with an azimuth of ∼315° and uncertainties of ± 5° close the terminus and up to ±15° further up-glacier with velocity magnitudes ranging from ∼50 m d−1 near the ice front to ∼25 m d−1 up-glacier with uncertainties ∼ ±6 m d−1 (Figs 3, 6, 7)
Summary
Velocity fields of tidewater glaciers are sensitive indicators of the various driving and resisting forces acting upon them (e.g. Howat and others, 2008). Satellite observations give a wellresolved two-dimensional (2-D) (horizontal) velocity field via feature or speckle tracking (e.g. Joughin and others, 2008; Ahn and Howat, 2011) but undersample the temporal variation. Jakobshavn drains ∼6% of the Greenland ice sheet (Bindschadler, 1984) and is likely to have accounted for ∼4% of the increase in sea-level rise rate for the 20th century (Houghton and others, 2001). It represents an important target for research aimed at understanding the overall health of the Greenland ice sheet
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
