CoastalFjord

fjords

Kullorsuaq

icefront

Local Fjords

Leveraging Local Knowledge to Measure Greenland Fjords

 
 

 

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Alison Glacier

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Polar Geophysics Group

Lamont-Doherty Earth Observatory

 

 

Background

ocean
The ocean interface at Jakobshavn glacier, Greenland's west coast.

Greenland

The Arctic has held a fascination for scientists for well over a century. In that time scientists have been observing and collecting measurements to improve our understanding of this unique region, yet the remoteness of the area and the difficulty and expense of working in extreme Arctic conditions have left large areas unsurveyed and many questions unanswered. Greenland is an important area of focus because it is covered by an ice sheet, one the last two large expanses of ice on Earth. Measuring two miles thick in the center and 1.7 million square kms in size the Greenland ice sheet has helped to cool the climate for all of human history. Additionally, melting of ice from the two ice sheets (Greenland and Antarctica) into the world's ocean will affect global sea level causing it to rise. Satellite and airborne measurements from programs like NASA's IceBridge tell us Greenland's ice sheet is changing, with surface melt increasing and glaciers along the coastline accelerating. A network of weather stations around Greenland provide information on a warming atmosphere, but few water measurements in the fjords exist. Water measurements are needed to fully understand the process driving the melting.

RIgnot
Edited image form Rignot et al, 2012 showing modeled warming of ocean water from ocean currents. Anomaly from period 1992-2009. Shows much of northern Greenland undergoing a 2 degree C warming from 2001 to 2009. Click on the image to enlarge.

The Ocean

The Greenland coast is lined with glaciers moving ice from the ice sheet down fjords to the ocean. This constant movement of ice into the ocean has accelerated over the last few decades with Greenland now contributing a larger amount to sea level rise. Scientists estimate it is currently contributing almost one quarter of our sea level rise behind the two other big contributors, thermal expansion of the warming ocean water (~ half) and melting mountain glaciers (~ a quarter). Understanding what is causing this acceleration of ice into the ocean is an important.

The ocean interacts directly with Greenland's tidewater glaciers. Scientists believe that warming ocean water moving up onto the shallow continental shelf and flowing in deep troughs up to, and under parts of the glacier are melting these glaciers from below. Rignot et al., 2012 worked with modeled simulations to examine the movement of warming subsurface ocean water directed by currents around Greenland. They found that warming ocean water from off shelf uses troughs in the continental shelf to move below the cooler seasonal mix layer to be rapidly delivered directly into the fjords. This warm water can then move down the fjords directly to the glacier and begin the melt process unless there is some be type of shallow sill blocking the flow.

Collecting ocean measurements over varied seasons is critical for better understanding this process. This project is designed to build that capacity in the local community with partnerships with local fishermen and school groups to collect and share ocean data.

 

 

 
       
   

LDEO

This project is funded through LDEO Climate Center with additional funding from NASA Interdisciplinary Program & logistical support from NSF. | contact us | web master

 

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