Please select your home edition
Edition
Collinson and Co

Understanding the Ocean's role in Greenland Glacier melt

by Woods Hole Oceanographic Institution (WHOI) on 19 Jul 2014
Sermilik Fjord, into which Helheim Glaciers drains, in August 2011. Nicholas Beaird
We, as long term sailors and boaters are very interested just what kind of shore lines and oceans we leave our grandchildren. The islands of the Pacific are a major cruising destination and as sailors who have been there realise they are particularly vulnerable to global warming.

So we ununashamed in our desire to spread the message.


The Greenland Ice Sheet is a 1.7 million-square-kilometer, 2-mile thick layer of ice that covers Greenland. Its fate is inextricably linked to our global climate system.

In the last 40 years, ice loss from the Greenland Ice Sheet increased four-fold contributing to one-quarter of global sea level rise. Some of the increased melting at the surface of the ice sheet is due to a warmer atmosphere, but the ocean’s role in driving ice loss largely remains a mystery.

Research by scientists at Woods Hole Oceanographic Institution (WHOI) and the Univ. of Oregon sheds new light on the connection between the ocean and Greenland’s outlet glaciers, and provides important data for future estimates of how fast the ice sheet will melt and how much mass will be lost. The study was published today in Nature Geosciences.


'Over the past few decades, many glaciers that drain the Greenland Ice Sheet have accelerated, thinned and retreated,' said the study’s lead author, Rebecca Jackson, a graduate student in the MIT-WHOI joint program in oceanography. 'Scientists have noticed a link between glacier behavior and warming waters off the coast of Greenland, but we have very few direct measurements of ocean waters near the glaciers or at what time scales they vary, which are needed to understand what’s happening there.'

Currently, scientists think that the accelerated rate of ice sheet melt might be due to warmer ocean waters melting on the underside of the ice, where the glaciers extend into the ocean. Little, however, is known about this 'submarine melting' – it has not been directly measured at any of Greenland’s major outlet glaciers, and scientists have limited information about the ocean temperature or circulation near the glaciers, which, they think, will impact the melt rate.

To begin to tease apart the mechanisms in this dynamic system, scientists needed more data.

Between 2009 and 2013, the study’s co-authors –Jackson, WHOI physical oceanographer Fiamma Straneo and David Sutherland from University of Oregon – deployed multiple moorings in two fjords where the third and fifth largest outlet glaciers of the Greenland Ice Sheet terminate. In one study site, moorings were located in the middle of the fjord, in the upper fjord toward the glacier, and on the shelf outside the fjord. At the second study site, a cluster of moorings were deployed in the middle of the second fjord. The moorings collected extensive measurements of temperature and salinity at various water depths, with some measured ocean currents -- the first data to provide information about the fjords’s conditions from fall through the spring.


'Almost all previous studies of Greenland’s fjords were conducted during the summer when the waters are fairly calm, and were relatively brief – with no information about how fast water properties change or what drives those changes,' Jackson noted.

From their analysis of the data, the researchers found rapid fluctuations in ocean temperature near the glaciers, resulting from 'surprisingly' fast ocean currents in the fjords. The fjord currents, which reverse every few days, are driven by winds and ocean currents outside the fjord. These findings imply that changes in temperature in the ocean waters outside the fjord can be rapidly communicated to the glacier, through an efficient pumping of new water into the fjord.

'We see much more variability in the upper fjord than we would have expected,' Jackson said. 'Our findings go against the prevailing paradigm that focused on the input of freshwater to the fjord as a driver of new water into the fjord.'

Furthermore, the observed variability in ocean properties near the glaciers suggests large and rapid fluctuations in submarine melt rates. The scientists suspect the melt rate of the glacier varies with the temperature of the water near the glacier.


'These observations of ocean conditions near outlet glaciers are one step towards a better understanding of submarine melting and the impact of the ocean on the Greenland Ice Sheet,' Jackson said.

The research was funded by the National Science Foundation and the WHOI Ocean Climate Change Institute.
The Woods Hole Oceanographic Institution is a private, independent organization on Cape Cod, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean's role in the changing global environment. For more information, please visit Woods Hole Oceanographic Institution.

Festival of Sails 2017 660x82Pantaenius - Fixed ValueAllen Brothers MBW 660 Purchase Power

Related Articles

Great Barrier Reef managers and industry prepare for summer
Marine park managers, scientists and experts recently met for the annual pre-summer workshop Marine park managers, scientists and experts recently met for the annual pre-summer workshop to assess climate-related risks to the Great Barrier Reef over the coming months. Current predictions by the Bureau of Meteorology and National Oceanic and Atmospheric Administration are for a summer of average sea temperatures across the Great Barrier Reef.
Posted on 7 Dec
Introducing the Airbnb of the mooring and marina world
Have you ever struggled to find an available mooring, or do you have a mooring that is sitting vacant? Have you ever struggled to find an available mooring, or do you have a mooring that is sitting vacant? makefastmooring.com is aiming to solve this problem by connecting boat owners with those with vacant moorings or berths. With a growing number of moorings and marinas in New Zealand, Australia and around the world, makefastmooring.com allows people to find, rent and share moorings and berths.
Posted on 7 Dec
Princess to pay largest ever criminal penalty for vessel pollution
Princess Cruise Lines has agreed to plead guilty to seven felony charges stemming from deliberate pollution of the seas Princess Cruise Lines Ltd. (Princess) has agreed to plead guilty to seven felony charges stemming from its deliberate pollution of the seas and intentional acts to cover it up. Princess will pay a $40 million penalty– the largest-ever criminal penalty involving deliberate vessel pollution – and plead guilty to charges related to illegal dumping of oil contaminated waste from the cruise ship.
Posted on 2 Dec
Race for Water catamaran to be equipped with new hydrogen system
Race for Water will make it possible for the crew to free themselves of the need for fossil fuels during new mission. Race for Water will make it possible for the crew to completely free themselves of the need for fossil fuels during the new mission against the pollution of the oceans.
Posted on 26 Nov
Second Blog from onboard Perie Banou II
This is day 13 since leaving the mid Western Australian town of Carnarvon. Remote region. Beautiful town. This is day 13 since leaving the mid Western Australian town of Carnarvon. Remote region. Beautiful town. Kept cooler by the strong south winds, which make the trees bend and grow to the north. Carnarvon is nice, especially the months of September, October, November, and December. The wind is strong. Often near gale strength, with squalls and blue skies.
Posted on 15 Nov
Radio spectrum changes have been put into place in New Zealand
New Zealand, along with a number of other countries, has been required to change some maritime VHF repeater channels New Zealand, along with a number of other countries, has been required to change some maritime VHF repeater channels to make space for newly allocated international services for ship tracking and data services. On the October 1st, New Zealand moved a few private VHF repeater services, most Coastguard VHF repeater services, and all NowCasting weather services. An updated radio handbook and freq
Posted on 2 Nov
New Zealand Maritime radio channels set to change on 1 October
Before you head out on the water next summer there are some important maritime radio changes you need to know about. Before you head out on the water next summer there are some important maritime radio changes you need to know about. On 1 October 2016, New Zealand is changing some maritime VHF repeater channels, and NowCasting weather services, to make space for new international ship tracking and data services, and to make sure our VHF radio services are compatible with the rest of the world.
Posted on 20 Sep
Prototype aims to take on the Garbage Patch
A prototype aimed at achieving 'the largest clean-up in history' is deployed in the North Sea. As scientists look to find a way to rid the infamous Great Pacific Garbage Patch of thousands of tonnes of waste plastic, a prototype aimed at achieving 'the largest clean-up in history' is deployed in the North Sea.
Posted on 7 Jul
Marine Sustainability Conference with an expanded environmental theme
The event will not only revisit the dismantling and responsible recycling of leisure craft, but also engage in debate The event will not only revisit the dismantling and responsible recycling of leisure craft, but also engage in debate about whether the Boating Industry can effectively embrace the ‘Circular Economy’ and how it can interact with the environmental desirability of ocean and waterway conservation.
Posted on 27 May
Puteri Harbour Marina receives Level 3 Clean Marina Accreditation
The International Clean Marina Program is a voluntary accreditation program for marinas, yacht clubs, and boat clubs. Puteri Harbour is located at Iskandar Puteri, the narrow-most point along The Straits of Johor separating Singapore from the Asia continent. The prestigious waterfront development offers three marinas - public, mega yacht and a private marina - designed to cater to the sailing community.
Posted on 15 Apr