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Disko Bay Project at AGU

Posted by on Dec 16, 2014

Several members of the Disko Bay team presented preliminary findings yesterday at the annual meeting of the American Geophysical Union (AGU) in San Francisco.  According to their website, “With nearly 24,000 attendees, the AGU Fall Meeting is the largest Earth and space science meeting in the world.”  The poster, Using Coastal Ice Cap Records to Investigate Maritime Climate and Ice Sheet Processes in West Greenland, was on display in the Moscone West Poster Hall from 1:40-6:00 PM non Monday.

Other team members will also be presenting on related work at AGU:

Laura Stevens et al (including Sarah Das):  Hydrologically Induced Basal Slip Triggers Greenland Supraglacial Lake Drainages

Ashley Stevens, et al (including Karen Frey, Sarah Das, Matt Evans, Ben Smith, and Luke Trusel): Assessing the influence of sea ice conditions on outlet glacier retreat in Disko and Uummannaq Bays, West Greenland

Kenneth Mankoff, et al ( including Sarah Das): In-Situ Observations of a Subglacial Outflow Plume in a Greenland Fjord

Luke Trusel, et al (including Karen Frey and Sarah Das): Divergent trajectories of Antarctic ice shelf surface melt under 21st century climate scenarios

Other work being presented by each of the PIs or their students can be found here:

Karen Frey

Sarah Das

Benjamin Smith

Matthew Evans 




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National Ice Core Laboratory

Posted by on Aug 4, 2014

The following post was written by Ashley York.

If you’ve been following Matt’s blog, you’ll know that we worked hard in the field this April collecting firn cores and snow pit samples and completing radar surveys at five different sites across west Greenland. But the work doesn’t stop there. Our cores were shipped from Greenland on a ‘cold deck’ flight to the National Ice Core Laboratory (NICL) in Lakewood, Colorado outside of Denver. From June 30 to July 3, PI Sarah Das, her new PhD student Matt Osman (yes, we have yet another Matt joining the team, so we will refer to him as “Oz”), Luke Trusel (currently a PhD student at Clark University working with PI Karen Frey, but starting a postdoc at WHOI with Sarah in the fall), and I (a PhD student at Clark University working with PI Karen Frey) traveled to NICL to begin processing the ice cores we collected this spring.

The National Ice Core Lab is maintained by the National Science Foundation, the U.S. Geological Survey, and the University of New Hampshire.  The physical facility includes an archive freezer held at a temperature of -36°C where some of the oldest cores from all over the world are stored. There is also a cold laboratory held at a temperature of -25°C which is where we spent most of our time processing our cores. We couldn’t have done any of the processing without the help of NICL employees Geoff Hargreaves and Richard Nunn. For lots of great information about NICL and the frozen facilities visit

Cold lab doorThe door to the frozen lab at NICL. (Photo Credit: Sarah Das).

core racksOne hallway of the National Ice Core Laboratory’s archive at -36°C. (Photo Credit: Sarah Das).

We spent the first half of our first day getting the lab tailored to our needs. Ensuring the equipment, such as the saws, and especially the imaging system worked. In the afternoon of the first day, we got into a rhythm with everyone having different tasks as the core moved along and leaving the opportunity for people to take breaks at different times. It was important to stay hydrated and take breaks from the cold at any point when you felt cold to avoid not only frostbite, but also disorientation especially since we were working with saws. As far as the science goes, the most important thing to remember when handling an ice core is to know where the top is! In order to keep this consistent as the core moved around the lab from person to person, we always kept the top to the right. There are very helpful arrows indicating the top direction drawn throughout the lab so you don’t forget.

The first processing step was handled by Richard, who removed the core from its original tubing and layflat from the field. He then measured the length, diameter, and weight of the core. Using a saw, he then removed the top centimeter from the core so that it was now flat on top. These cut off portions are called “wings” and were saved and bagged for later use.

core measuringAfter measuring the core, Richard Nuun of NICL packs the core securely in the tray for the top cut. (Photo Credit: Sarah Das).

After the top portion of the core was cut off, it was digitally imaged. I turned to Luke for the following more detailed explanation of the imaging system at NICL. “The imaging system at NICL is an inline scanning system designed to create a visual archive of the core and allow for analyzing its physical properties.  You can think of it like a scanner or copying machine.  Each tube of ice core is placed on a tray and is slowly moved past a high-resolution camera sensor that records an image of the core at sub-millimeter scale.  Two LED lights on each side of the core illuminate features like melt layers, firn grain size changes, and cracks within the core. The images can be useful for analyzing annual layering (to determine how much snow fell in a year) and refrozen melt layer thicknesses (to determine how warm summers have been).”

imaged coreAn example of a firn core digital image. (Photo Credit: Luke Trusel).

After the digital imaging, Luke hand-drew some basic plots (on super cool meter-long graph paper made just for this!) of the core to take special care of noting what was a melt layer versus a break in the core, as they can sometimes be confused in digital form.

plotting coreLuke hand-plotting the core to double-check the digital images. (Photo Credit: Sarah Das).

After Luke plotted the core, he passed it along to Sarah. Sarah cut the three round sides that remained on the core off, making the core into a clean 5cm X 5cm square the length of the core. She also bagged the cut-off outer wings for later use.

cutting coreSarah cutting the core down to be square.

core cut squareAn example of the center of the core after all the outside edges have been removed. (Photo Credit: Sarah Das).

After Sarah cut the core down to be square, she passed it along to Luke who cut the interior square in half lengthwise, creating two 5cm  X 2.5cm sections for the length of the core. The first of these length-wise sections was bagged and saved for future use at Sarah’s WHOI lab.

core cut into 2 piecesLuke cutting the square core into two length-wise pieces. (Photo Credit: Sarah Das).

The second length of core was then passed to Oz and me. I cut the core into smaller 5cm X 5cm X 2.5cm discrete samples sections.

cutting small piecesAshley cutting the core into small discrete samples. (Photo Credit: Sarah Das).

Oz then bagged these samples and we stapled labels onto the bag to know what site and depth they correspond to.

os baggingOz bagging and labeling the discrete samples. (Photo Credit: Sarah Das).

Once we had our jobs organized during the second half of the first day, we were able to power through most of the cores on the following day, and leaving only a few to do on the morning of the third day. We processed a total of about 33.4 meters of core taken from four different sites in Greenland. Next year we plan to collect hundreds of meters of core from three final sites. Needless to say, we expect to be spending a bit more time at the National Ice Core Lab next summer.


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Nuus 1 and Ilulissat (take 2)

Posted by on Apr 28, 2014

This past Friday was the last day in the field for our team.  Ashley and I were back in Kangerlussuaq and I have posted some photos of a local hike to Instagram Icamera icon on right)

The rest of the team, Matt, Sarah, Ben, and Laura headed up from Qaarsut with a new pilot to Nuus1, our second site on the Nuussauq Peninsula.  Ben and Laura were dropped off first and they started the normal routine of getting the radar ready and installing the first GPS.  They quickly realized that the area had some small crevasses (only a few inches wide), but even small ones is an indication of tension in the ice and suggests the possibility of bigger, more dangerous ones. So Ben and Laura assessed the situation and directed the helo to a different landing spot.    Sarah and Matt worked on the core and found lots of hard melt layers and not much quality firn.  The snow pit was only about half a meter before they found an impenetrable ice layer.  The conclusion-Nuus 1 is probably not a candidate for future deep drilling.  As the photos show, though, it was a great day out on the ice cap.

P1040897Ben and Laura on the ground.

P1040910Sarah working on the core. 

P1040904The very shallow snow pit with a Leatherman for scale. 

P1040930The team on Nuus1.  Another stellar day in the mountains.

After the final field day, the field crew enjoyed another two days in Ilulissat.

IMG_1509Pano of the overlook for the huge bergs.  If you compare this one to the one from earlier in the week, you can see how much more ice has moved into the bay.  


P1050146Ben, Sarah, and Laura survey the big bergs. 


IMG_1520Final dinner in Ilulissat: The Greenlandic buffet: cod, salmon, cod liver, reindeer in cream, seal, smoked whale, roe, cod milt, and capelin.  

In about and hour we board a plane for Copenhagen-the final (unplanned) leg of our Greenland adventure!

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Holy _______ ! The continuation of The Most Ridiculous Day Ever at Nuus 2.

Posted by on Apr 26, 2014

You can fill in the blank with whatever you want, but “holy something,” yesterday was spectacular!  After sitting in the clouds for two days, we got to sit on the top of those clouds for the whole day.  Low coastal and valley cloud was thin enough for Peter to get the helicopter above it and to our first field site on Nuussuaq Peninsula.  Ben had identified several sites on Nuussuaq and numbered them.  For the last two days we had been talking about which sites to prioritize and “Nuus 2″ got the call.  These sites are very different from the Greenland Ice Sheet.  The GrIS where we worked is just vast and flat in all directions.  The Disko and Nuussuaq sites are small ice caps on top of mountainous terrain.  I usually thing of an ice cap as been a pretty large area of ice “capping” a similarly large area of last-kind of like a mini-ice sheet but not nearly big enough to get the “sheet” designation.  But the caps on Nuussuaq are quite small-more like an “ice plateau” on top of a mountain.  The Disko site is big enough to land a Twin Otter on, but not Nuus 2.  We walked around the whole thing in about an hour and the slopes were much steeper.  It only took a little bit  of walking away from our work site before we were too far downhill to see the other folks.  In fac,t at one point we asked Peter to move the helo down to one of our GPS sites.  When he was in the air we realized that we were much closer than we thought; after he moved the helo we ended up back at the work site and, even though the helo had only moved about 100 yds downhill, we could not see it.

If you have been reading other posts you know to also hit the Instgram link to the left to see more photos.

You also know by now that we have been doing the same work at each field site: 1) drilling a core (usually about 5-9 meters deep), 2) digging a 1-2 meter snow pit and taking two sets of samples-one for stable isotopes (H and O) and density (rectangular holes), and one for MSA, Cl, and other chemistry (round holes), and 3) doing radar transects to map the subsurface ice layers and thicknesses and taking GPS measurements to see how the glaciers are moving and accumulating snow.  Because we have been repeating the same tasks, it has worked well to divide into teams of 2: Matt and Sarah core, Ashley and I (and the Twim Otter pilots on the GrIS!) dig the pit and sample, and Laura and Ben run the radar and GPS.

For the Disko and Nuussuaq sites, I jumped in with Ben and Laura so we could move as a rope team of 3, which is safer on glaciated terrain where the crevasse danger is unknown.  The auxiliary benefit of being on the radar rope is that you stay warmer moving around, and as you can see from the photos, you also get to walk all around the site and see the sites!  Because Nuus 2 is steeper, those walks away from the main work site quickly got you some unique views.

So today, Ben and Laura and I went up first.  The flight up the valley was just ridiculous in terms of scenery.  Like at Disko, Ben set to work on the radar set up while Laura put in the first GPS and I probed the area; we were very confident from Ben’s studies of hi-res satellite imagery that our landing site was crevasse-free but it seemed like a prudent thing to do anyway.  Once the radar was ready we set off on on our scenic walk.  We would walk following a GPS track that Ben had mapped on this satellite imagery on his computer and transferred to a handheld Garmin.  At the end of each track or “run” we would stop and Ben would reset his orange ground penetrating radar and Laura would reset the ice penetrating radar that I was towing behind me.  At each of these stops Ben would take off his pack, lay it on the ground,  and open it up to where his radar controls were located and I would fish out my camera and snap pictures.  As a result, most of my photos that have Ben in them show him “praying to the radar gods,” as he said. After the first radar circuit around the landing site, the helo came back with the rest of the team and they set to work on the other tasks.

At the end of the day, Ashley and Ben and I headed down to Qaarsut on the first flight down and organized gear for me and Ashley to take back to Ilulissat.  When the rest of the team came down, we said our goodbyes and then Ashley and I boarded the helo for the flight back with Peter.  As I explained earlier, Peter had to head back to Copenhagen today so he had to return to Ilulissat yesterday so he could catch a flight today to Kanger and then on to Copenhagen, plus our end-of -trip logistics got confused due to a number of factors that all converged.  Originally we were all going to come back to Kanger yesterday and today.  Because we were behind on field days due to weather, we were trying to use what would have been down days in Kanger waiting for the Air National Guard C-130 to take us home on Monday.  Right as we were trying to figure out if we could get a new pilot back to Qaarsut for the weekend, we found out that the C-130s were all grounded (world wide is what we heard) and that the first C-130 would be coming on Tuesday and then not leaving until Wednesday or after.  That meant that we needed to fly home commercially.  To complicate matters, there are only flights from Ilulissat to Kanger on certain days and the A-Star can only carry 3 passengers and a limited amount of gear.  Very long story (trust me!) short is that it worked best for me and Ashley to fly out with Peter and then fly down to Kanger today via Air Greenland (yet another aircraft-a Dash 8) while the rest of the team does one more Nuussuaq site and then makes their way to Kanger on Monday (because there are no flights over the weekend).  When we all meet up in Kanger we then fly to Copenhagen, spend the night, and then fly back to Boston via Newark (yeah Newark!), except for Ben who can fly to Iceland and then direct to Seattle.  Complicated!

So what follows is a string of photos showing the days events.

 IMG_6677Peter, our pilot, with his machine.

IMG_6680Ben prays to the radar box of goodies


And to the GPS.  This was the most amazing view I think with the peaks sticking out the clouds. 


A little shift to the right for the rest of the view of the above photo. 


Plotting our next course. 


This is the real “Ben prays to the radar gods” photo.  I have lots of these photos.  


Tough place to be but someone has to do this science!


The big view!


Hack-a-zoom.  I love this valley and this peak.  I could not stop trying to photograph it.


Laura takes in the view. Being a grad student has its challenges.  This is not one of them.


Team 2 arrives.  Matt taking a picture of me taking a picture of him taking a picture of me . . . 


Matt E, aka the cosmonaut, drills into Nuus 2.  We pulled 11 m of core from the hole below.  


Looking down the hole.  Held the iPhone real tight!


Taking the ice’s temperature. 


The tubing that the core goes into is called “lay-flat.” It is flat but hollow.  It gets stapled at one end and labelled so that when core is ready, it can be slid in.  Then it goes into the silver core tube and eventually into an insulated core box to be shipped cold back to the US.  


“Comrades, you must eat to stay warm!”


Flying back down to Qaarsut.  Out in the distance are the huge rock fortress islands whose tops were sticking out of the clouds and in the foreground is a large iceberg frozen into the sea-ice.  


That rock cairn on the right of the foreground peak is the one we hiked to two days before when we were grounded in the weather.  


Peter slowed down so I could get this shot of the airport hotel without the big water tank next to it.  



After refueling in Qaarsut, we took off back to Ilulissat.  On the right of this island is a town called  Uummaannaq. No I did not hold down keys-that is how it is spelled. Greenlandic is full of a’s, u’s, i’s, l’s, t’s, and m’s and n’s.  Very cool language to see in print.   


Then we turned up this valley and flew right back past our field site and up over the clouds on the other side.  


Peaks coming through the clouds. 


My favorite valley and peak wrapped in clouds.  


Islands in the sky. 


My favorite valley (again!) 

IMG_8498Crazy cool!



Looking up a long valley that cuts through the peninsula.  


 As we got out over the ocean the clouds thickened and Peter took us down to the cloud tops to look for a hole.  Along the way we got chased by the helicopter fairy.  


After Peter found a hole and dove down through it (a little stomach in the throat!) we spotted this gem!



90% of a berg is underwater so we are seeing both the “tip of the iceberg” and the tip of the bottom.  Presumably these connect below were we can see.   


 Some scale!


Ilulissat with the truly colossal Jakoshavn bergs around the point.  

IMG_6717Parting shot on a gorgeous day.  

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Nuus 2 (aka The Most Ridiculous Day Ever)

Posted by on Apr 25, 2014

I know, that is a very tantalizing title for a short post, but it is 11 pm and a longer telling of the days events will have to wait until tomorrow.

But here are three photos to whet the appetite:


On the flight up to the field site, which is right on top of the dome on the left at the head of the valley system.  

post-1Grainy iPhone zoom but give a great sense of the drama of the position of the field site.  We were way up high on a small ice cap surrounded by mountains that were sticking up out of a much lower layer of cloud.  Words can’t describe it (though I will try them later!)


post-2My after-school Milton crew, this is for you.  This is one of the shallower pits we have sampled, but from here I have two different kinds of snow/ice samples and Matt (Dr. Evans) is starting a core.  These will all go to Milton for us to work on!

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