TY - JOUR T1 - Acquisition of a 3 min, two-dimensional glacier velocity field with terrestrial radar interferometry JF - Journal of Glaciology Y1 - 2017 A1 - Voytenko, Denis A1 - Dixon, Timothy H. A1 - Holland, David M. A1 - Cassotto, Ryan A1 - Howat, Ian M. A1 - Fahnestock, Mark A. A1 - Truffer, Martin A1 - De La Peña, Santiago KW - glacier flow KW - glacier geophysics KW - glaciological instruments and methods AB - {\textless}p{\textgreater}Outlet 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.{\textless}/p{\textgreater} UR - https://www.cambridge.org/core/product/identifier/S0022143017000284/type/journal{\_}article ER - TY - JOUR T1 - Sensitivity of Pine Island Glacier to observed ocean forcing JF - Geophysical Research Letters Y1 - 2016 A1 - Christianson, Knut A1 - Bushuk, Mitchell A1 - Dutrieux, Pierre A1 - Parizek, Byron R. A1 - Joughin, Ian R. A1 - Alley, Richard B. A1 - Shean, David E. A1 - Abrahamsen, E. Povl A1 - Anandakrishnan, Sridhar A1 - Heywood, Karen J. A1 - Kim, Tae-Wan A1 - Lee, Sang Hoon A1 - Nicholls, Keith A1 - Stanton, Tim A1 - Truffer, Martin A1 - Webber, Benjamin G. M. A1 - Jenkins, Adrian A1 - Jacobs, Stan A1 - Bindschadler, Robert A1 - Holland, David M. KW - glacier-ocean interactions KW - Ice Dynamics KW - ice shelves KW - ice streams KW - marine ice sheet instability AB - ©2016. American Geophysical Union. All Rights Reserved.We present subannual observations (2009–2014) of a major West Antarctic glacier (Pine Island Glacier) and the neighboring ocean. Ongoing glacier retreat and accelerated ice flow were likely triggered a few decades ago by increased ocean-induced thinning, which may have initiated marine ice sheet instability. Following a subsequent 60{%} drop in ocean heat content from early 2012 to late 2013, ice flow slowed, but by {\textless} 4{%}, with flow recovering as the ocean warmed to prior temperatures. During this cold-ocean period, the evolving glacier-bed/ice shelf system was also in a geometry favorable to stabilization. However, despite a minor, temporary decrease in ice discharge, the basin-wide thinning signal did not change. Thus, as predicted by theory, once marine ice sheet instability is underway, a single transient high-amplitude ocean cooling has only a relatively minor effect on ice flow. The long-term effects of ocean temperature variability on ice flow, however, are not yet known. VL - 43 UR - http://doi.wiley.com/10.1002/2016GL070500 ER -