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Greenland Aquifer Expedition: Back in the Office

April 22nd, 2013 by Maria-Jose Viñas

By Lora Koenig

Watching dogsleds go by in Kulusuk.

Watching dogsleds go by in Kulusuk.

Well, I am back in Greenbelt, Maryland, typing with warm fingers in a climate-controlled office with high-speed Internet and drinking fountain just down the hall. After fieldwork, I am always thankful for things I generally take for granted, like being able to charge my laptop by simply plugging it into an outlet. There is no longer a need fill a generator with gas and then start it just to charge batteries. Aw, the comforts of home!  (We all had safe trips back to the US and have returned to our home institutions last week.)

For the last blog post of the season, I decided to pull together a few of my favorite photos from our trip to give you a sampling of the great fun we get to have while doing this kind of research. The most fun I had during this trip was on our final day in Kulusuk: we were invited to the Kulusuk School to with the children in the upper grades (who speak some English) about our work. I regret that we do not have any pictures of this event, but we were giving our presentation and letting the students run our small ice core drill, thus neglecting picture taking. The school in Kulusuk has about 70 students and includes all grades. The building has lots of windows and is very bright inside — it is one of the prettiest schools I have been in, with lots of open space, a small kitchen, library and a gym. I especially liked the entrance to the school, which was equipped with plenty of coat hangers and boot racks for the students to shed their cold weather gear as soon as they come inside. Though we were there talking about science, the school in Kulusuk is known for their art. We were hosted by the art teacher, Anne-Mette Holm, and after our talk got to attend one of her classes where the students were making wooden sculptures. We also got to see other student projects including weaving, toy making and furniture making. Quite a portfolio!  The students’ art has traveled the world, being shown at different expeditions across the Arctic. (Check out pages 11 -15 of this document for some examples of the children’s art work under Anne-Mette’s tutelage.)

While our visit to the school was definitely the top highlight of the trip here are a few others highlights in pictures.

The northern lights (Aurora) never got old and were out almost every night.

The northern lights (Aurora) never got old and were out almost every night.

The view out the window from our dinner table in Kulusuk at sunset.

The view out the window from our dinner table in Kulusuk at sunset.

Sunset in Kulusuk.

Sunset in Kulusuk.

Seeing mountains from our campsite on the ice sheet, a nice change from the typical flat white ice sheet.

Seeing mountains from our campsite on the ice sheet, a nice change from the typical flat white ice sheet.

Watching Clem dig a really big hole for the thermistor control boxes.

Watching Clem dig a really big hole for the thermistor control boxes.

Seeing the transition between the flat ice sheet and the fast flowing outlet glaciers.

Seeing the transition between the flat ice sheet and the fast flowing outlet glaciers.

Catching a ride in the airport luggage carts.

Catching a ride in the airport luggage carts.

So those were some of the highlights of the field work and now it is time to work with the data we gathered. In the week we have been back, we have already started to analyze our data. We see that, as expected, the densities in the firn (aged snow) above the aquifer are higher than expected and that there is more water than originally predicted. We still need more data to fully understand what this water trapped in the Greenland ice sheet means for sea level rise. We need many years of data to understand how and if the aquifer is changing with time… but remember this was an exploratory mission. When we set out, we were not even sure if our drills would even work. There was a chance they would have just frozen in place and we would not have gotten any data. This was a high-risk mission due to the weather in the region and all the new things we were trying. We came back with all the data we set out to get and, quite frankly, I am surprised. We had a large team that helped with this project including the field team, logistics support, airport support, the NASA and NSF support teams and all of you for your well wishes and interest in our research. Thanks to all! Until next time, stay cool :-)

Greenland Aquifer Expedition: Shallow drilling

April 18th, 2013 by Maria-Jose Viñas

By Ludovic Brucker

We were on Greenland’s ice sheet for only a week, but despite the short deployment, we had to accomplish two main science objectives. The first was drilling two deep cores into the firn (aged snow) and ice (30- and 65-m deep, respectively), to insert temperature probes that will record temperature evolution at various depths. Secondly, we wanted to drill shallower cores (7 to 15 m) to record the snow’s density vertical profile using a neutron density probe – and this is what this post is going to be about: the shallow drilling that we did and the measurements we took in these holes to monitor the snow and ice layering and their properties.

To drill the shallower cores, we used the same solar-powered drill as in 2010 and 2011 in Antarctica during the Satellite Era Accumulation Traverse. It is composed of four parts, which I’ll describe from top to bottom. The first segment contains the motor to rotate the other parts. The second and third parts are barrels — one for the snow and ice chips, and the other to store the one-meter long drilled core. The fourth part, the cutters, is screwed into the latter barrel. Cutters are critical since they are the sharp elements that cut the snow, firn, and ice. Since snow and ice having different properties, the cutters for snow and ice are different. For instance, if we use the ice cutters at a smaller angle, we will drill at less depth during each barrel rotation. Where we drilled, part of the winter snow melts during the summer and when it refreezes, it forms a thick ice layer every year. The snow that did not melt will slowly evolve to firn, and, eventually, ice. Because of the different, we thus had to switch cutters during our drilling: otherwise, we would have not been able to drill through the past summer ice layers.

Ice cutters screwed at the bottom of the barrel, which rotates into the ice to extract an ice core.

Ice cutters screwed at the bottom of the barrel, which rotates into the ice to extract an ice core.

Lora showing how to extract the first meter of the snow core.

Lora showing how to extract the first meter of the snow core.

Jay drilled cores through the water contained within the firn (the aquifer). We used our smaller drill, since we did not want to enter in contact with the aquifer. Therefore, each of our cores was shallower than the water layer’s top and each was drilled in about an hour.

Once we had drilled the hole, we observed the layering of the snow and ice cover using a video camera. Thanks to the camera’s flashlight, we were able to identify the thick 2012 summer ice layer (about 3 m below the surface) that formed after a massive surface melt event, as well as the previous summer ice layers. Our team used this sensor to monitor a water-filled hole for the first time. We were all really excited to see the inner upper part of the ice sheet!

Lora holding the video camera that she will send down in the hole to monitor the snow and ice layering.

Lora holding the video camera that she will send down in the hole to monitor the snow and ice layering.

Rick and Clem enjoying the first view of the firn's internal stratigraphy

Rick and Clem enjoying the first view of the firn’s internal stratigraphy

We also used this useful device to check the position of the temperature probes and to ensure that the entire line of temperature sensors was straight inside the hole. The first time we inserted the camera into the water in the hole, we were amazed to discover the amount of air bubbles released by the firn, which propagated toward the water/air interface. The aquifer is composed of ice, water, and air. These elements are present several meters below the surface, which means they’re under pressure. Once we drilled the cores, the pressurized air bubbles in the vicinity of the hole migrated toward the hole and then moved upwards to the water/air interface.

Our last scientific activity was to monitor density with 1-cm vertical resolution using the neutron density probe. We moved the probe along the borehole at a speed of about 5 cm per minute. This sounds like a time-consuming measurement, but measuring density manually is significantly more labor intensive since one must saw the core into segments and then measure each segment’s length, diameter, and weight.

To be more comfortable during the drilling and while recording our scientific data, we always paid particular attention to staying behind our wind break.

Lora and Ludo drilling behind a windbreak during a windy day, with a lot of blowing snow near the ground.

Lora and Ludo drilling behind a windbreak during a windy day, with a lot of blowing snow near the ground.

A windbreak is composed of a simple plastic tarp supported by bamboo sticks and held by bungee cords. While we were in Kulusuk preparing our departure to the field, Jay told us several times that bamboo sticks would be critical pieces of equipment while we worked on the ice and that they had to be in mint condition to offer the best resistance to wind. So we spent more than a day in Kulusuk fixing and reinforcing bamboo sticks, using wires and tape. And I am glad we did it!

Working in the warehouse to improve the bamboo sticks that we'll use in the field as wind breaks.

Working in the warehouse to improve the bamboo sticks that we’ll use in the field as wind breaks.

Once we had collected all the data needed from a hole, we packed our equipment, removed the precious windbreak and the bamboo sticks, and either headed toward a new site few hundreds meters away, or went to the cook tent for diner. That’s how our busy days in the field went!

Greenland Aquifer Expedition: Radar Days on the Greenland Ice Sheet

April 16th, 2013 by Maria-Jose Viñas

By Clément Miège

Hi there! Today I will give you some background on the radar measurements we collected in southeast Greenland. The radar we deployed is sensitive to snow density changes and to wet snow. The main goal of the radar measurements was to provide information about the spatial variations of the top of the aquifer (a water layer trapped within firn, or old snow).

The radar we used is made by GSSI, a company specialized into geophysical measurements, and it has a center frequency of 400 MHz. In snow and firn, the electromagnetic waves sent by this ground-penetrating radar can image approximately the first 50 meters of a dry snowpack. The layers that we observe in radar measurements show the snowpack stratigraphy (density changes). If there is water within the snow and firn, we observe a really strong radar echo in the radar profile. Then, by dragging the radar around, we are able to see how this water layer evolves spatially.

Here is the radar system in action, with Ludo pulling the sled. It can be a pretty tiring job with the wind and the cold. The balaclava was an absolute must to protect your face from the freezing temperatures.

Here is the radar system in action, with Ludo pulling the sled. It can be a pretty tiring job with the wind and the cold. The balaclava was an absolute must to protect your face from the freezing temperatures.

Mostly to lighten our helicopter loads, but also to exercise a bit, we decided to pull the radar sled with skis. But it ended up not being an easy job at times: some of our field days were really windy and cold, so we needed to be warmly dressed and have our face well-protected. In addition, we carried a backpack with the GPS unit and a battery – they became pretty heavy after an hour of pulling the radar. Ludo and I set up the rule of not doing more than 2 hours of survey at a time, which corresponded to about 5 km total.

Once on the ice sheet, as soon as the helicopter took off, we turned on the radar. Indeed, we wanted to make sure that we had been dropped over water and then find the best location for our drilling site. By looking at the radar profile, we identified the water layer (great!) and we converted its depth from electromagnetic wave two way travel time to meters. We observed that over a 2-km transect, the top of the aquifer varied up to 10 meters. By knowing this variation, we were able to pick the site location at a depth that fitted our science needs.

An example of the radar profile observed: the bright reflector represents the top of the water layer. Other internal reflections can be seen -- they are linked to previous summer layers, which are denser.

An example of the radar profile observed: the bright reflector represents the top of the water layer. Other internal reflections can be seen — they are linked to previous summer layers, which are denser.

The advantage of doing this preliminary radar survey is that we then knew before drilling at which depth the drill would encounter water and penetrate into the aquifer. And the good thing was that the radar picked the right water depth in both drilling sites! The radar ended up being a really good tool to extend spatially the localized information obtained by the firn cores.

Doing some radar at sunset with no wind was just so great!

Doing some radar at sunset with no wind was just so great!

For the radar survey, we were doing some elevation transects, to see how the water layer changed with the local topography, and some grids and bowties to extent spatially the core site stratigraphy. We stayed within a radius of 2 km from our camp.

Overall, doing the radar surveys was a great experience. It’s incredible to think that we were skiing with liquid water right below us, while surface temperatures averaging -15C.

Finally, concerning the radar setup, we have already some improvements in mind for the next time. For example, the GPS unit and its antenna need to be in the sled, maybe mounting the GPS antenna on a corner of the radar sled, trying to keep the all setup stable. That will allow us to drag the radar longer. We will work on that for our next radar adventure!

Greenland Aquifer Expedition: The Long Way to Kulusuk

March 27th, 2013 by Maria-Jose Viñas

By Lora Koenig

As I write this post, on Tuesday, March 26, our team is spread across the globe. I am at Dulles airport near Washington, D.C. waiting to get on a plane that will fly through the night to Iceland, and then onto Kulusuk, Greenland, tomorrow. My gear includes a thick parka, boots, cloths, medicine (just in case) and even some chocolate for Easter, all packed in a nice water-tight bag so no snow will get in it. Jay, Clem and Ludo are already in Kulusuk and Rick is waiting in Iceland to get on the same plane that will take me to Greenland tomorrow.

Some of my gear, before packing.

Some of my gear, before packing.

How did we all get so spread out? Well, it was mostly caused by the unpredictably of weather canceling flights and the limited number of flights into Kulusuk (there are only two each week — on Wednesdays and Saturdays).

To figure out our logistics, we have to start with our put-in date that is scheduled for April 1. “Put-in” is when we go from Kulusuk to our field site on the ice sheet to put in our camp and start the science. A put-in date of April 1 means we all need to arrive in Kulusuk at least one flight before the connection flight, to give us a cushion. Rick and I will arrive on the March 27 flight, which is the last flight with a cushion. We would have all arrived on this flight but the Easter Holidays threw a wrench in our schedule: all services will be closed in Kulusuk from March 28 to April 2. So Jay, Clem and Ludo arrived early to buy some extra food, fill fuel canisters and make sure all the science cargo arrived safely.

To get to Kulusuk, we go through Reykjavik, Iceland. Clem and Ludo got an extra day in Iceland because they had a boomerang flight. “Boomerang flights”, common in the polar regions, happen when a plane takes off for a location and then the weather takes a nasty turn, so the aircraft has to return to its point of origin. So you take a long plane ride but end up right back where you started – that’s one of the reasons we plan lots of extra days in our schedule for delays.

Beyond getting people to the field, we have to make sure all of our gear is there as well. Our gear was shipped the first week of March – different shipments were sent from Kangerlussuaq (Greenland), Greenbelt, MD, Salt Lake City, UT and Madison, WI. We have about 4,000 lbs of gear, including the science equipment, camping equipment, generators, and food. Jay, Clem and Ludo have confirmed that everything arrived safely except for our deep drill, which, proof of Murphy’s Law, happens to be one of the most important pieces of gear. We knew it had been delayed in shipping for a few weeks and right now, it’s in Kangerlussuaq, waiting to get on a plane to Nuuk and then onto Kulusuk. Hopefully it will arrive Tuesday, but the latest news is another delay due to airplane maintenance that canceled the flight to Nuuk. There are still two flights that could get the drill there in time, so we are watching this closely.  If the drill does not arrive in time, we will have to delay the field work.

Right now the weather is beautiful in Kulusuk, so hopefully all the pieces (people, gear and weather) will come together for an on-time field season. Now I will board a plane, hopefully get some sleep, and send my next update from Greenland.

Salinity Processes in the Upper Ocean Regional Study (SPURS): SPURS Epilogue (The First)

October 15th, 2012 by Maria-Jose Viñas

By Eric Lindstrom

“Ships at a distance have every man’s wish on board.” — Zora Neale Hurston

Actual spurs.

So, we are back in port in the Azores Islands of Portugal. Knorr 209-1 was a fabulous voyage and it did feel that we had many a man’s wish on board. Those included wishes for our data collection from all the scientists involved in SPURS and well wishes from all the family members of the expedition and finally the good wishes of you, my blog audience.

The Knorr SPURS science group.

Thank you all for following my SPURS adventure so far. The saga continues for another year. We have instruments in the water and more expeditions ahead (in March and September 2013). Each expedition will be slightly different in nature but overall working toward the SPURS goal of understanding the surface salinity maximum in the Atlantic and the water cycle on the planet. I’ll be going into a different mode of blogging now, to provide you updates on the science and the observations as the year goes along. With good fortune, I will get back to sea for the final leg of SPURS in September 2013. If you would like another voyage blog from the Sargasso Sea in 2013, let your voices be heard in the comments section below!

After several days of riding a lumpy swell from Tropical Storm Oscar, we were greeted by the magnificent sight of greenery and civilization at Ponta Delgada on the island of São Miguel.

Ponta Delgada’s water front.

Panorama of Ponta Delgada’s waterfront.

The Knorr in Ponta Delgada.

The expedition was a success scientifically.  We got our sensor web in the water for the coming year: three moorings, 25 Argo floats, 18 surface drifters, three Wavegliders, three Seagliders, and a Lagrangian Mixed Layer Float. We completed a wide variety of shipboard deployments: 764 Underway CTD casts, 100 CTD/LADCP Stations, 30 Vertical Microstructure Profiles, 33 AUV missions, three Slocum glider turbulence missions, and a full suite of continuous measurements including ocean velocity profiles, thermosalinograph and meteorology/fluxes. We accomplished the objectives we had laid out for us – deploy the sensor web (week 1), do a control volume survey around the moorings (week 2), and map a mesoscale ocean feature (week 3). We were able to squeeze in some extras, like a 24-hour time series in the saltiest water and pick up a glider from the French expedition in August.

The expedition was a success for NASA and WHOI.  We even caught the attention of the International Space Station and had a great 30-minute chat with Commander Sunita Williams about research in sea and space and the strong connections between the space program and oceanography.

The expedition was a success in interagency cooperation. SPURS is led by NASA, but has enormously important contributions from NSF, NOAA, and the Office of Naval Research.  It takes a village to put on a good oceanographic process study!

I created a “SPURS Illustrated Campaign Summary” from our Knorr expedition. I will make it available to all of you as part of a future post. There will also be movies available from the Space Station call and from the expedition, which are still in the editing process.

Your questions and comments on SPURS are always welcome. Use the comments section of any of the posts and I will get the message. Your interest and curiosity provides directions for future blogs and helps me put into words some of the technical aspects of SPURS that may not be fully understood.

Thanks you all for again following along on our Knorr SPURS expedition. There is much more to come, so stay tuned!