Sensitivity of Pine Island Glacier to observed ocean forcing
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 < 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.
Authors: Christianson, Knut, Bushuk, Mitchell, Dutrieux, Pierre, Parizek, Byron R., Joughin, Ian R., Alley, Richard B., Shean, David E., Abrahamsen, E. Povl, Anandakrishnan, Sridhar, Heywood, Karen J., Kim, Tae-Wan, Lee, Sang-Hoon, Nicholls, Keith, Stanton, Tim, Truffer, Martin, Webber, Benjamin G.M., Jenkins, Adrian, Jacobs, Stan, Bindschadler, Robert, Holland, David M.