Posts Tagged ‘Greenland’

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Greenland Aquifer Expedition: Greenland firn aquifer expedition: Season two!

March 19th, 2014 by Maria-Jose Viñas

By Clément Miège

Hi there! I am Clément Miège, a Ph.D. student at the University of Utah and I am going to take you along with us to our second expedition to the southeast region of Greenland, to investigate the physical properties of a firn aquifer. And what is a firn aquifer, you might be wondering? It’s a reservoir of perennial water (that is, water that doesn’t freeze in the winter) that is trapped within the compacted snow layer (or firn) of the Greenland ice sheet. If you didn’t follow last year’s edition of this expedition and/or you want to learn more about the firn aquifer, here are some readings I recommend:

  • Our team’s blog posts from last year will give you some background material on the set-up of the expedition and work over the ice sheet. It describes the travel to our field site in Greenland and the techniques we used on the ice sheet to do a first measurement of the volume of water within the firn aquifer.
  • To complete this story, my team and other researchers recently published a journal article where we described how this aquifer was serendipitously discovered in the spring of 2011 when we were sampling regions of high snow accumulation. The paper also describes how we first mapped the aquifer using a combination of firn cores, ground radar and airborne radars.
  • Finally, we published another journal article following up on the blog posts from last year and determining the volume of the water trapped in the firn aquifer at a specific location. We obtained this volume by comparing the mass of a wet firn core taken inside the aquifer to a core taken in an neighboring area of dry snow. If you assume this water volume is constant throughout the entire firn aquifer (which spreads over an area larger than Western Virginia!), that would correspond to 140 gigatonnes of water stored. To say it in a different way: if the water runoff the ice sheet, it would raise sea levels worldwide by 0.016 inches (0.4 mm).
  • And if you don’t feel like reading scientific papers right now, NASA put out a story about our findings, too.

We are now getting ready for another expedition to Greenland to further monitor the firn aquifer. This year, our four main tasks will be to maintain our equipment currently in place (which performs temperature measurements), collect additional measurements (with a radar), install a weather station, and try traditional ground-water techniques to date the water and calculate its permeability. I will explain in future blog posts why these measurements are important.

I will be part of a smaller team this year, since only three out of the five members of the first-year team are joining. Rick Forster and I will represent the University of Utah, while Ludovic Brucker comes from NASA Goddard Space Flight Center.

The Greenland Aquifer team in 2013.

The Greenland Aquifer team in 2013.

Here is the photo of the team from last year, from left to right; Jay, Ludo, Rick, Lora and I. Lora and Jay won’t be coming to the field this year (we sure will miss them!) If you want to know a bit more about each team member (current and former), you can check this blog post from last year.

Even when we haven’t set a foot in the field yet, the expedition to Greenland started about two months ago with organizing the logistics. Logistics can sometimes be underestimated, but it takes a lot of effort prior to getting to the field to prepare and test the scientific equipment and other field supplies, such as camping gear, food, and power sources.

For this expedition, all of the science equipment (GPS, radars with different frequencies — 5MHz to 400MHz–, piezometers, ice-core drill) was gathered from different institutions in Utah to be packed here and shipped to Kulusuk. Most of the non-perishable food and camping gear was left for over-winter storage after last year’s expedition in a warehouse in Kulusuk, to save on shipping costs.

On March 3 this year, the Utah gear left for Greenland; we’re talking about 800 lbs. of gear that left Salt Lake City on a truck headed to the JFK airport in New York, where it was flown to Reykjavik (Iceland) and then to Kulusuk (Greenland). We got a phone call early this week from our shipping company to confirm that all our equipment made it to Greenland — great news!

Gear packed at the office (left) and ready to leave the shipping facility at the University of Utah (right). We will see this gear again in Greenland!

Gear packed at the office (left) and ready to leave the shipping facility at the University of Utah (right). We will see this gear again in Greenland!

These last days have been really busy, gathering the last items for our science research, and also personal equipment. Yesterday, I was working at Blue System Integration in Vancouver, BC with a colleague, Laurent Mingo, who is developing IceRadar, an ice-penetrating radar system for the scientific community (see this website for additional info). Laurent has been working on an experimental beta version of the current radar that will allow us to penetrate through the firn aquifer to try to image the bottom of the aquifer gradually transitioning from water-saturated firn to ice.

Even if most of the scientific equipment is already shipped, there are always some last-minute important items that we end up adding into our suitcases (like the low-frequency radar). As a brief anecdote, last year, Rick traveled with a pelican case as a checked bag – inside, there was a bunch of wires hooked up to a datalogger. We were aware that it looked kind of suspicious, so it was a bit scary to go through customs with it! Me, I traveled with a 60-meter long thermistor string weighing over 50 lbs. in my checked bag, because the fabrication and calibration took longer than expected and we weren’t able to ship it ahead of time with the rest of the equipment. This year, luckily, most of the heavy equipment was ready on time and we are carrying only a couple random items in our checked bags.

We are starting our journey this week, leaving the U.S. on Thursday evening for Reykjavik, the capital of Iceland. After a day in Reykjavik, we will leave mid-Saturday on a 2-hour short flight that will take us to Kulusuk, Greenland. We are hoping for good weather; last year, Ludo and I “boomeranged” on our first try due to poor visibility at the Kulusuk runway.

In this old map from the US army (from 1941) you can see the location of the small city of Kulusuk in Southeast Greenland (red star), just below the Arctic Circle (~66.5°N). Our field camp on the ice sheet is represented by a white star. The map can be found at the Polar Geospatial Center.

In this old map from the US army (from 1941) you can see the location of the small city of Kulusuk in Southeast Greenland (red star), just below the Arctic Circle (~66.5°N). Our field camp on the ice sheet is represented by a white star. The map can be found at the Polar Geospatial Center.

Kulusuk is our first stop in Greenland. We will be staying at this small village for a few days in order to re-pack our field gear, test that everything is working well (stoves, generators, tents, science equipment, etc.) before going to the field. If we are lucky, we might see one of the polar bears that sometimes come close to town in this time of year.

Colorful houses make up the town of Kulusuk in Southeast Greenland. The shores of the fjord are covered by sea ice in the winter.

Colorful houses make up the town of Kulusuk in Southeast Greenland. The shores of the fjord are covered by sea ice in the winter.

After a couple of days, we will be heading to our fieldwork location on the ice sheet. A helicopter from Air Greenland will drop us and our cargo at our study site; it will be an about 45-minute commute.

That is it for this introduction; our next blog post will be from Greenland!

All the best,

Clément

Greenland Surface Melt Study 2013: Gearing Up for Greenland: Part 2

November 1st, 2013 by Colleen Brooks

In early September, I drove down to Wallops Flight Facility to set up our GPS base station in preparation for the test flight. The test flight is to verify that everything is working as expected, and to do some calibration, since the C-130 is a new platform for the Land, Vegetation, and Ice Sensor (LVIS). LVIS gathers data by sending out short laser beam pulses that bounce off the ground and give us the elevation of the terrain. Calibration ensures that we can pinpoint to within an inch where the laser hits the ground. We need to know exactly where the instrument is, and what it is seeing on the ground.

We use GPS receivers both on the ground and in the plane to track the position of the instrument. That’s where I come in. I set up the GPS ground station, which consists of GPS receivers and an antenna. In the field we usually get a rundown shack and we have to set up our own antenna. The Wallops GPS building was luxurious in comparison. It was spacious, air-conditioned, and had a permanent antenna built in, which meant I didn’t have to set up a tripod. I hooked up three ground receivers to the antenna, verified that they were working and started recording data. We do this for up to five days, in order to calculate precisely the location of the ground antenna.

GPS receiver

GPS receiver aboard the NASA C-130 set up for testing

I also tested the GPS antenna on the plane. It’s a different model from the ground antenna and is bolted to the top of the plane. A cable runs down from it so we can hook up the receivers. Just like for the ground receivers, I verify that they are working and recording data correctly.

GPS antenna

GPS antenna aboard the C-130

The C-130 is a rugged cargo plane. One of our instrument racks, filled with equipment necessary to operate LVIS, was sitting on the hangar floor outside the plane, waiting to be moved into place and bolted down. I got a look at the current state of the in-flight facilities and took pictures for the team back home. There had been much discussion on the subject since some of our flights may last up to 10 hours. We never imagined we’d be discussing these issues when we were in school! It’s all part of the field work experience.

Antenna and receiver connected

GPS antennas and receiver wired up in the C-130 ready for test flights

At the end of the day, I collected and verified the GPS data available and left the ground receivers running. Everything was working as expected, so it was time for me to make the three hour trek back home. No traffic and beautiful scenery made for a pleasant drive.

Greenland Surface Melt Study 2013: Gearing Up for Greenland: Part 1

October 31st, 2013 by Greg Clarke

Editor’s note: In fall 2013, researchers aboard a NASA C-130 traveled to Greenland to study changes in the ice sheet and sea ice following the summer melt season. Other airborne campaigns, like NASA’s Operation IceBridge, study changes on an annual basis and this is the first large-scale airborne survey of seasonal change. The C-130, equipped with a pair of Land, Vegetation and Ice Sensor (LVIS) laser altimeters, will carry out surveys of land and sea ice from Oct. 31 to mid-November and will resurvey many of the same areas flown by IceBridge during its 2013 Arctic campaign.

In late August, David Rabine and I headed down to Wallops Flight Facility in Virginia to start LVIS instrument installation for NASA’s Greenland airborne campaign.

It was my first time at Wallops and I was thoroughly impressed with the amount of airborne activity that takes place there. It seems like every 15 minutes there is a plane taking off or landing! Once there we saw the C-130 that will carry our two LVIS instruments. It looks like a great platform for scientific measurement. It has a huge cargo door in the back that allowed us to literally roll the pallet with all the equipment and the two instruments on board.

C-130 on the ramp at Wallops

NASA’s C-130 aircraft on the tarmac at Wallops Flight Facility in Virginia. Members of the LVIS instrument team are installing equipment in preparation for the upcoming IceBridge Greenland campaign.

C-130 window with credit card stickers

: The C-130 also had a sticker with major credit card logos on one of its windows. Perhaps this means they accept them for the in-flight entertainment.

Another benefit of the C-130 is the space available inside, which allows us to use four equipment racks without having to worry about space, and put the two LVIS instruments side-by-side. This will let us build a great data product. We spent a week populating our equipment racks, and by the end of it we had most of the equipment for the regular LVIS instrument mounted into its appropriate rack. Next came the equipment for the Global Hawk version and after finishing the equipment racks, we installed the two LVIS instruments onto a custom built platform that holds them in place.

Equipment racks

Two equipment racks filled with operating equipment for the LVIS instruments.

We were very fortunate that our trip to Wallops lined up with a test flight of one of NASA’s Global Hawks, an uninhabited aerial vehicle that’s taking part in another NASA mission, the Hurricanes and Severe Storms Sentinel, or HS3, mission, and which the smaller version of LVIS has flown on before. As luck would have it, on the morning of Aug. 20 the Global Hawk took off on the runway that was closest to our airplane hangar. We were able to get a front seat view of the takeoff.

Global Hawk taking off

NASA’s Global Hawk taking off from Wallops Flight Facility on Aug. 20.

Greenland Aquifer Expedition: Tracking Temperatures in the Aquifer

April 24th, 2013 by Maria-Jose Viñas

By Clément Miège

Hi there! Today I have another story to share with you! It’s about the tracking of the temperature evolution of the firn aquifer temperature by using two thermistor strings that we set up in the two holes made by Jay (see Jay’s post on drilling for details).

By tracking temperatures over a year, we will observe the firn heating mechanisms in the summer with the melt from the surface of the ice followed by water infiltration in the firn. In the winter, we will get a sense of the refreezing processes from the cold surface air, which cools the upper part of the firn and we will observe the persistence of the firn aquifer over the years.

To achieve this, we installed two thermistor strings with two different lengths: 30 and 60 meters. The shorter string has 60 sensors on it, sampling every half-meter. The longer one will only get a temperature reading every 2.5 meters but it will record deeper temperatures. Both strings are set to collect data every hour for an entire year, assuming the batteries last that long (hopefully!) The temperature chain is called a thermistor string because each sensor is a thermistor, a type of resistor sensitive to temperature changes. After measuring a resistance change, calibration curves allow us to retrieve temperature changes.

The thermistor-string story started in Utah, when we received the equipment late from the manufacturers, giving us only 5 days to work on it before leaving for Greenland. We realized that integrating the whole system together with the satellite uplink would take most of our last prep days.

It was definitely too late to ship the thermistor equipment with the rest of our gear, so Rick and I traveled with it in our checked luggage! I ended up with a 50 lbs of spool coiled with about 60 meters of cable in a suitcase. Rick had a black pelican case as his checked bag, with the second thermistor string, datalogger, ARGOS antenna and other pieces of hardware. We learned how to travel light, bringing minimal clothing, and wearing the cold-weather clothes in the airplane so we were able to meet the airline luggage restrictions – it definitely made for fun travels!

At the Kulusuk Hotel, in southeast Greenland, we finished integrating the thermistor string, mostly by picking the right data-transmission rate to the satellite in regards to our battery consumption estimates. Having the ARGOS satellite uplink will let us receive temperature data via email every day from the field site and tell us almost in real time what the temperatures are in the two holes.

In the field, shortly after drilling each hole (to avoid water refreezing due to cold air down the hole), we lowered the thermistor string down and backfilled the hole with surface snow. Then, we used the Felics drill to make a 4-meter hole to anchor the long pole that holds the ARGOS antenna.

Lowering the second thermistor string down the 30-meter hole.

Lowering the second thermistor string down the 30-meter hole.

On that day, the 20-knot katabic winds were blowing a lot of snow, so we used a mountain tent as a snow-proof environment to work with the electronics before dropping off the case in its hole. To give you a taste of the wind speed: Rick was charging one of the thermistor-string battery and the wind was so strong that it blew the small 1kw generator off…. crazy! When the winds finally died down, we buried the case in a 2-meter deep snow pit, because we wanted to prevent the case from being exposed to surface densification and melt during the summer.

Digging a deep snow pit for the thermistor case.

Digging a deep snow pit for the thermistor case.

Last check on the electronics, to make sure all the wires are tightened before closing the box -- next opening in one year!

Last check on the electronics, to make sure all the wires are tightened before closing the box — next opening in one year!

That is it! The box is down the hole.

That is it! The box is down the hole.

After backfilling the snow pit, the only evidence at the surface of the temperature strings is the top of the pole with the ARGOS antenna and a red flag!

After backfilling the snow pit, the only evidence at the surface of the temperature strings is the top of the pole with the ARGOS antenna and a red flag!

We are hoping to recover the case with the datalogger next year, but we are not sure if the ARGOS antenna will still be sticking out, because this sector of the ice sheet is getting a lot of snow accumulation in the winter. We will use a metal detector to find the metal pipes left near the case.

Because this is likely my last post for this expedition’s blog, I would like to thank the all team for this great adventure and everybody that was supporting this exciting research. Until next time!

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 :-)

Notes from the Field