EAPS

Brent Minchew
NSF Postdoctoral Fellow
British Antarctic Survey

Oceans and Ice:
How Ocean Tides Inuence Inland Ice Flow and What it Teaches Us
About Ice Sheet Evolution

Oceans play an important role in the long-term evolution of ice sheets and
drive much of the recent shrinkage in the Greenland and Antarctic ice
sheets. Our understanding of ice-ocean interactions is limited because both
the forcing from the oceans and the response of the ice sheets are complex,
involving poorly understood processes that play out over timescales that
can be dicult to observe. Here, I will discuss a natural experiment in which
we use periodic changes in horizontal ice ow speeds driven by the rise and
fall of ocean tides to study the coupling between oceans and ice ow. In our
study area, tidally driven vertical motion of the oating ice shelf modulates
horizontal ice ow in both oating and grounded ice. Flow speeds are
modulated to nearly 100 kilometers inland of the grounding line (where ice
goes aoat) and vary by as much as 20% about the mean in the grounded
ice stream. To understand why ocean tides inuence ice ow and what this
phenomenon can teach us about the dynamics of ice-ocean interactions, we
developed a new method for quantifying spatiotemporal variations in ice
velocity using remotely sensed data. The results, which form the rst-ever
3-D, time-dependent surface velocity eld, reveal the spatiotemporal
characteristics of the response of ice ow to ocean tidal forcing. I will discuss
how we derive this new kind of dataset, what the data reveal about glacier
dynamics and ice-ocean interactions, and how these methods, combined
with the wealth of remote sensing data currently being collected, will
improve our understanding of ice sheets and other dynamical systems.

Reception to follow lecture
all are welcome to attend