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Icebergs and fjords

Icebergs form when the face of a marine terminating glacier calves sending huge chunks of ice into the sea. Icebergs flux freshwater from ice sheets to the sea, they track and influence ocean circulation in the fjords, and sometimes they destroy instruments along the way.

photo credits: M. Andres


At the head of Sermilik Fjord in southeastern Greenland is Helheim Glacier, a prolific iceberg producer.

img_6391Helheim’s icebergs are advected through the fjord to the East Greenland shelf.  Some of Helheim’s icebergs have deep-reaching keels…

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…and those keels can wreak havoc. This subsurface float—pushed below its pressure rating by a passing iceberg with a particularly deep-reaching keel—imploded. With funding from the National Science Foundation (PLR-1332911) and the Woods Hole Oceanographic Institution, we have been working on ways to study the fjord environment with instruments that can be deployed on the seafloor, safely out of reach of the iceberg keels. Read more about our project below…

PIES being deployed in Sermilik Fjord in August 2013.

How we measure

Our team has been using pressure-sensor equipped inverted echo sounders (PIESs) to study the heat content and iceberg dynamics in Sermilik Fjord. photo credit: N. Beaird

What we measure

Each PIES measures time series of round-trip acoustic travel time, bottom pressure and bottom temperature at high sampling rate and for a long duration. photo credit: M. Andres

What we learn

An algorithm automatically detects icebergs in a PIES’s travel time record. From this we deduce iceberg speed and estimates of the iceberg draft. image credit: A. FitzMaurice