November 9th, 2015 by Maria-Jose Viñas
By Christine Dow and Ryan Walker
Editor’s note: Ryan Walker and Christine Dow are two researchers at NASA’s Goddard Space Flight Center who will be spending more a month in Antarctica to study the response of the Nansen Ice Shelf to ocean tides, while blogging from the field.
Christine Dow and Ryan Walker, on the day of their departure for Antarctica.
Christine: Hi! My name is Christine Dow. I’m a postdoctoral fellow and my main area of research is using numerical computer models to examine water flow pathways develop underneath the Antarctic ice sheets. I am particularly interested in what controls the growth and drainage of large lakes that form underneath the ice. Despite being chained to my desk most of the time, I love to go into the field. Not that it’s very easy to directly observe water flow underneath the ice sheets, but I find going to visit glaciers always reinforces the large scales of processes that are reduced to a few lines of code on my computer. I have previously lived and worked on glaciers in the Canadian Rockies; Devon Island in the Canadian High Arctic; and on the Greenland ice sheet. However, this will be my first trip to the Antarctic, and has been top of my bucket list for a very long time.
Ryan: And this is Ryan Walker. I’ve been with the Cryospheric Sciences Laboratory at NASA’s Goddard Space Flight Center and the University of Maryland since 2012, following five years at Penn State University. I’m a glaciologist now, but most of my background is in mathematics and I’m primarily an ice sheet modeler. This will be my second trip to the Antarctic — I was on a research cruise studying sea ice with the Australian Antarctic Division when I was in grad school — but this will be my first time on the continent. This trip resulted from the Korea Polar Research Institute inviting me to their symposium in 2014. Although they were mostly looking for my advice as a modeler, our discussions eventually led to an offer to collaborate in the field, for which I’m very grateful. I’m looking forward to getting a close-up view of what I’ve been modeling for years.
Christine: We’re almost off. It’s the culmination of more than six months of preparation involving not just a little bit of stress and appearance of more gray hairs. Ryan and myself will be heading to the South Korean Jang Bogo station in Terra Nova Bay for a month to measure flexure of ice tongues due to ocean tides. We will be installing five GPS stations that will record uplift of the ice and two tilt sensors that will record very subtle changes in ice uplift and motion. The GPS will be placed on regions of the ice that are technically floating on the ocean water, whereas the tilt meter will be placed just about the grounding line where the ice is on land. We have very carefully planned exactly where these will go but, I’m sure, as with all fieldwork we will have to be somewhat flexible with our aims. There are logistics to think of, like weather for helicopter flying, including wind (which we’ve heard is quite brutal in that region) and crevasses in the ice which a) we don’t want to fall down and, b) we don’t want the equipment to fall down. For this reason, we have back-up plans and back-up plans for the back-up plans. However, in the end I think going with the flow is probably the best idea.
In terms of organization, the most important/stressful part so far has been our shipping deadline at the end of September. Holes were drilled, plywood was hacksawed and sanded, metal conduit was sawed and of course lots of packing and repacking. All of this equipment is (hopefully) awaiting our arrival in New Zealand before travelling down with us on a plane to the land of ice and snow. All that is left to do is make sure we have enough socks, etc. and to make sure we catch the multiple flights. The route is going to be Washington Dulles to San Francisco to Sydney (with a lovely 8 hours to entertain ourselves between flights) and then finally to Christchurch. We leave Saturday evening (Nov. 7) and arrive Monday evening (Nov. 9)! Good thing that we have a couple of days to acclimatize before we catch the flight down to the Antarctic. We will be in touch from the southern hemisphere!
July 14th, 2014 by Kate Ramsayer
Very few people get to fly 65,000 feet above Alaska’s glaciers. And even fewer get to fly over ones they share a name with. But on Friday, as pilot Denis Steele flew NASA’s ER-2 aircraft from Palmdale, California, to Fairbanks, Alaska, he snapped a picture of the scenery below – including Steele Glacier in the southwestern corner of Canada’s Yukon territory.
From NASA’s ER-2 aircraft, pilot Denis Steele saw glaciers in southern Alaska and Canada — including the Steele Glacier, the horizontal feature in the center of the image, and the Donjek Glacier (lower right). (Credit: Denis Steele)
Steele and the ER-2 team, along with NASA scientists, engineers and others, are here in Fairbanks to fly a laser altimeter – MABEL, or Multiple Altimeter Beam Experimental Lidar – over melting summer sea ice, glaciers and more. It’s a campaign to see what these polar regions will look like with data from ICESat-2, once the satellite launches and starts collecting data about the height of Earth below. Gathering information now allows scientists to get a head start in developing the computer programs scientists will need to analyze ICESat-2’s raw data.
MABEL and other lidar instruments are flying on the ER-2, which provides a high-altitude perspective. In the next three weeks, the plan is to cover melting sea ice, glaciers, vegetation, lakes, and more.
Steele wasn’t the only one looking out of the plane windows on flights north. Kelly Brunt, a research scientist at NASA’s Goddard Space Flight Center, spotted a wildfire in Eastern Washington. The fire, burning in steep terrain, resembled an erupting volcano.
A wildfire burns in Washington, just east of the Cascades. (Credit: Kelly Brunt)
Over the weekend, the team settled into Fairbanks and a hangar at the U.S. Army’s Fort Wainwright, downloading data from the transit flight and ensuring the instruments are ready to fly when the weather allows. Cloudy skies over key sites means the ER-2 won’t fly today (Monday), but the team will check the weather tonight and see if it clears enough to fly the first science flight on Tuesday.
Want to follow MABEL and the ER-2? Check back here, and also check NASA’s flight tracker: http://airbornescience.nasa.gov/tracker/
Yep, we’re in Alaska! A moose along a road east of Fairbanks. I’ll call her Mabel. (Credit: Kate Ramsayer)
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.
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.
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.
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!
April 22nd, 2013 by Maria-Jose Viñas
By Lora Koenig
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 view out the window from our dinner table in Kulusuk at sunset.
Sunset in Kulusuk.
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.
Seeing the transition between the flat ice sheet and the fast flowing outlet glaciers.
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 🙂
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.
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.
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.
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.
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!