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Archive for the ‘Lee Corbett’ Category

When the C-130 plane touched down on the Greenland Ice Sheet, its landing skis cracked and crushed the icy surface of the ‘ski-way’, jolting passengers from their reveries and their seats. Despite my earplugs and the otherwise-deafening roar of the plane, I could still hear the skis grind through icy, hard-packed snow as we taxied to the field station. We had arrived at the highest point of the Greenland Ice Sheet—3,200 meters above sea level.  Even though conversation was impossible through the noise, the anticipation and excitement of the students and summit crew was palpable. We silently sprung into action putting on our final warm layers, fetching and securing packs and then impatiently glancing and smiling at each other until the plane stopped and the door opened. We stepped out into the freezing, white territory one by one—still in eerie silence due to our ear protection—boots crunching on the snow, walking slowly in the thin air to the “Big House.”

Arriving at Summit Station. Photo by Courtney Hammond.

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Quentin Watson (left), Chef, and Ken Jessen, Camp Manager.

The “Big House” is the center of activity at summit, hosting a large kitchen, numerous tables for congregation, a futon, the manager’s office, and an extremely sunny bathroom (I’ve never needed sunglasses to brush my teeth before). The building sits atop tall, metal stilts, which, on good days, keeps it above winter snowdrifts. When we arrived from our flight, the house was warm and smelled like delicious food—the first of many incredibly tasty meals we would indulge in at summit. After lunch we were given instructions from the camp manager, Ken, about general rules of living/surviving at summit. These rules ranged from making sure to wash hands or use sanitizer before every meal and at every possible opportunity (there was sanitizer conveniently stashed in every corner of camp), to using the highest level of caution and sense at all times, as being evacuated from camp, is, well, highly undesirable and risky. Next, we heard instructions about staying healthy from the medic, Ben, who is a part of the incoming IGERT cohort. After the logistics talks and welcomes adjourned, we were set loose at camp.

“Big House” at Summit. Photo by Courtney Hammond.

It was vast, silent (save for the tractors moving snow during the day), and white-to-grey, depending on the sky. While bamboo flagpoles permeated the immediate area of camp— marking walkways, science equipment, and boundaries—the extent of flat, unadulterated snow past the summit encampment was truly astounding. We had plenty of time to ponder the grandeur of it all while we took turns working inside the pit. To keep warm during our outdoor sampling stints that would last 3-4 hours at a time, we made videos, took pictures, learned a tap dance routine and sometimes trekked back to the big house for a quick cup of tea. The temperature hovered around -18 C throughout our stay, with winds coming and going and the sun ever-present.

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“Walking into the Expanse” by Courtney Hammond.

The transition between nighttime and daytime hours gets blurred at the poles since it is light all the time during summer. However, the temperature was noticeably colder when I would walk across the snowfield to “tent city” at bedtime. Orange tents in perfect rows are set up at one edge of camp, and researchers and students visiting summit sleep there during their stays. Since we were the only researchers visiting at the time, we each had our own palatial “Arctic Oven,” which has a layer of insulation to trap solar energy during the day. Since our first three days at summit were overcast, we did not have such luxury of a toasty tent at night.  My personal sleeping accommodation consisted of a cot, a hot water bottle at the foot of my sleeping bag, a fleece liner, and a -20 F sleeping bag (I may have also put my own zero-degree bag over my cot as extra comfort—psychological comfort, if anything). Between the tent flapping viciously in the wind, the blinding sunlight (it seemed sunnier inside the bright orange tent than out!), the high elevation, and the bitter cold, sleeping did not come naturally to me on the first night at summit. It was my first night sleeping on the Arctic ice ever, and it was all completely foreign—including the choice method of peeing in a water bottle in the middle of the night as alternative to trekking to the outhouse.

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“Tent City”

By the 3rd night, however, I was STOKED. What an amazing, simple, lifestyle. When  ‘home’ is a little arctic hut, and the day’s duties include collecting snow and firn samples with the goal of better understanding the Earth’s past climate, a unique rhythm can set in, both individually and within the group. Upon leaving summit, the only illness I feared I was getting was what our professor, Ross Virginia calls “Arctic Fever”—the need to return year after year after year for this totally unsurpassed feeling of adventure, camaraderie and discovery.

Igirls at Summit

Excited to be Women in Science. Photo by Courtney Hammond.

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While Steph’s permeability measurements (see the post from July 23) served as our chief scientific focus on the ice given their direct relevance to her dissertation work, they were far from the only in-situ data we collected.  We measured many standard physical properties (stratigraphy, density, temperature, etc.) in the 1.4-meter deep snow pit to gain both practice with field instruments and familiarity with snow properties.  In addition, I elected to take hourly temperature measurements to complement data I am analyzing in my current project.

1) A qualitative look at the pit “stratigraphy” (layering of the snow):

Ali looking at Layers
 Ali and Jess looking at layers of “hoar,” comprised of very coarse and porous grains.

We looked at the snow from top to bottom, observing changes in its appearance and labeling it on a spectrum from coarse to fine.  Steph has experience characterizing snow coarseness from the Antarctic firn cores she analyzes and shared her knowledge with the group.  Lee also conducted a “hardness test” by looking at the relative depths to which she could push a pencil into the snow with the same force.

2) Density: We measured the density of the snow continuously from the surface to the base of the snow pit with a small, sharp metal tool.  We generally expect density to increase with depth (as more and more snow builds up, the underlying snow compacts), but the density values and amount of change vary between sites and times of year.

The metal tool cuts into the snow, leaving a 3-cm high rectangle in the pit wall.  We measured the weight of the extracted snow on a balance and divided that by the known volume of the tool to give density.

Density Measurement
Chelsea handing Lee the density cutter filled with snow, ready for weighing.

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The pit wall with holes left from density measurements.

3) Temperature: Nine thermometers placed in the pit wall provided a temperature profile with depth.  I elected to take regular readings of near-surface snow temperatures in the hope that they could elucidate the source of some variability in Summit temperature data I’ve been analyzing back in Hanover.  Additionally, I was interested in seeing how deeply the daily fluctuations in temperature are “felt” in the snowpack.

Temp Log
The top five thermometers, spaced at 2, 4.5, 7, 13, and 20 cm from the surface.

Our scientific experiences in the field were complemented by talks that we’d prepared for each other (Mary gave a talk on firn which virtually the entire camp attended!) and interactions with other scientists on base.  One in particular, Kevin Hammonds, is a grad student at the University of Utah and gave us a tour of the “Mobile Science Facility” (MSF) of the Integrated Characterization of Energy, Clouds, Atmospheric state, and Precipitation at Summit (ICECAPS) project for which he is a summer technician.  He showed us the myriad of radar, LiDAR, and microwave instruments and cameras designed for looking at the microstructure of clouds and snowflakes.  Check out the cool pictures from his blog!

Being at a site of both current and past groundbreaking science was humbling in and of itself.  For those of us who study ice and climate, seeing the top of the GISP2 borehole provided a highlight of the trip:

GISP2
The ice core from the Greenland Icesheet Project (GISP2) reaches two miles down to the base of the ice.  It archives over 100,000 years of Earth’s history and has provided much of what we know about climate change today.

Summit provided an ideal classroom for sharing glaciological knowledge; I think we were all bummed that our time there was so short!

Group shot at Summit
The group on the stairs of the “Big House” at Summit Station.

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This post was written by Professor Mary Albert

Our NSF-IGERT studies at Summit, Greenland are designed to investigate aspects of snow, firn, and ice core interpretation, as part of our larger look at polar environmental change in Greenland. Coming to the site of the GISP2 ice core, where ice core scientists first realized that climate could change in less than ten years, is a real adventure for our graduate students! Being here now to witness a new change and to measure its effects  — the first significant melt at this cold high-altitude site since 1889 – is but one of the great opportunities to showcase the excitement of working in polar science!  The National Science Foundation has facilitated this unusual and extremely educational opportunity in this brief round of science here at Summit, the very top of the Greenland Ice Sheet.

Our third-year IGERT student, Kaitlin Keegan, came up earlier to conduct snow science with the JSEP group of high school students; she then left Summit before our arrival to venture on to the NEEM site. I have thoroughly enjoyed the honor of leading the discoveries with our first-year IGERT students – what a bright group of PhD students they are!

IGERT Cohort 3 at Summit
The Dartmouth IGERT group at Summit. From left to right: Mary Albert, Stephanie Gregory, Lee Corbett, Jessica Trout-Haney, Chelsea Vario, Alexandra Giese, and Ian Baker

We made stratigraphy, density, and permeability measurements on important layers in the snow.

Steph and Mary looking at Firn Sample
Stephanie Gregory and Mary Albert discuss a snow sample for a permeability measurement.

We collected samples of the refrozen melt layer to take home for more detailed measurements. Hey, even our panda got a taste of ice science!

Panda eating Ice

Being at Summit immediately after the first big melt there since 1889 has been a great science & education opportunity!  We are all very thankful to the NSF IGERT program for supporting these students, the NSF Office of Polar Programs for allowing us to come to Summit, the Air National Guard for getting us to Greenland, and to all of the wonderful folks at CH2Mhill Polar Services for providing superior field support, including the extremely capable camp staff at Summit Station.  A very hearty Thank You to you all!

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Thursday was a great day for physics in Kanger! Our mighty group was fortunate to partake in a tour of the internationally recognized research facility, known as Kellyville. Located about 16km from the KISS center in Kangerlussuaq, Kellyville is a small research community operated by SRI international in cooperation with NSF and the Danish Meteorological Institute. They specialize in upper atmospheric studies, and house a wide range of instruments installed by researchers from around the world.

July 19, 2012
Approaching Kellyville, we got a nice view of the layout of this microcommunity of small houses, one main instrument building, and the large radar with parabolic dish.

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Inside the main instrument building.

Our tour began with a walk through the main research building, where an on-site electrical engineer along with research engineer in the Department of Physics and Astronomy at Dartmouth, David Mcgaw, explained to us how the collection of intricate instruments housed here are currently being used for atmospheric and ionospheric projects around the world. These techniques are being used to study phenomena ranging from the physics of the auroral emissions, to the dynamics of solar storms!

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The indoor instrumentation was definitely amazing, however the most impressive of these instruments stood outside of the building…

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The Incoherent Scatter Radar!

Equipped with a 32m steerable parabolic dish, the Incoherent Scatter Radar collects direct measurements of the ionosphere via a radar beam into the upper atmosphere.

All in all, we had a fantastic day and learned a lot about atmospheric physics!

More updates on our next adventure to follow shortly…but until then, we’d love to hear from YOU! Is there anything in particular you would like to hear more about? We welcome suggestions!

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Just a quick note to say that IGERT cohort 3 has safely arrived in Greenland! We got here yesterday evening, and are about to begin our adventures today. Here’s a quick recap of our trip north:

We arose around 4:00AM yesterday morning in order to catch a 5:00AM shuttle from our hotel to the New York Air National Guard base in Scotia. After waiting around at the base for a few hours, we finally boarded the LC-130 plane around 8:30AM.

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Boarding the LC-130. Note the cool colored logo: a dragon at the north pole!

The LC-130s to Greenland are not known for their comfort, and this flight was no exception. The aircraft is very loud, and all passengers have to wear ear protection for the entire flight. It’s also cold, so most opt to wear down jackets and boots. Lastly, and most importantly, it’s quite cozy! The tail of the plane is filled with cargo, and passengers sit on webbing seats in the front. Alas, the flight lasts about six hours.

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Cozy accomodations on the flight to Kangerlussuaq.

The best part of the flight was, of course, stopping in Goose Bay, Labrador. Most flights from Scotia to Kangerlussuaq have to stop to refuel, and we were lucky enough to be on one of these flights. What could make refueling so exciting?? The ice cream, of course! We were happily greeted in Goose Bay by assorted ice cream sandwiches and coffee, and all enjoyed the refueling stop immensely.
The sky was mostly overcast while we flew over Canada and over water, but cleared up as soon as we got to Greenland’s coast, and we were treated to spectacular views as we flew inland to Kangerlussuaq. Most of the scientists on the flight huddled around the two windows in the tail, pointing and yelling over the roar of the engines.

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Beautiful views of the landscape west of Kangerlussuaq. Note the awesome glacial geology features!! I almost wept with joy when I saw the partially eroded looping end moraine at the terminus of the glacier on the right side of this photo.

Upon arrival in Kangerlussuaq we were greeted with hot dinner, hot showers, and numerous other scientists from around the world. All in all, a great trip northward!

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Greetings from the newest crew of IGERT students! We’re about to begin our journey to Greenland and encourage you to follow along. We’ll be blogging regularly throughout our trip and will be sharing photos and stories of our adventures, our science, and our outreach activities. Our cohort is made up of five Dartmouth PhD students with various specialties: Lee Corbett (Earth Science), Ali Giese (Earth Science), Steph Gregory (Engineering), Jess Trout-Haney (Ecology and Evolutionary Biology) and Chelsea Vario (Ecology and Evolutionary Biology). We will all be blogging and providing perspectives from our various disciplines. A number of Dartmouth faculty will also be joining us throughout our trip, including Mary Albert, Matt Ayres, Ian Baker, Lenore Grenoble, and Ross Virginia, as well as Research Assistant Courtney Hammond.

As a preview of coming attractions, a rough itinerary of our travels is as follows:

    • July 17: Drive to Scotia NY, the location of the 109th New York Air National Guard Base
    • July 18: Fly to Kangerlussuaq, western Greenland, with the National Guard
    • July 20-23: Study snow and glaciers at Summit (the center of the Greenland Ice Sheet)
    • July 26- August 5: Fieldwork in Kangerlussuaq, including a week-long backcountry trip
    • August 6-18: Science outreach in Nuuk (the capital of Greenland)
    • August 19-21: Brief return to Kangerlussuaq
    • August 22: Fly home

IGERT Travel Plan 2012

Map of Greenland showing the IGERT crew’s travel plan for field season 2012. Locations of ice core drilling sites are shown with stars; contours indicate approximate ice sheet surface elevation. Red arrows show our travel route, with red numbers denoting the order of events. Map created by Lee Corbett.

Note also that I’ll be heading up to Thule, northwestern Greenland, on August 9th for the continuation of my dissertation fieldwork. I’ll be blogging on that trip as well.

Please follow along as our adventures continue!

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Erich Osterberg and I spent the past week along the ice margin in Thule, Greenland, working with a variety of methods: lake coring, cosmogenic nuclide dating of glacial erratic boulders, and radiocarbon dating of fossil vegetation. This work will ultimately become part of my thesis, and was a great way to investigate the Thule area from a variety of angles. Our goal is to study the Holocene (the most recent ~10,000 years) climate history of Thule, and in particular a period of warm climate ~6,000 years ago (called the Holocene Climatic Optimum).

We collected sediment cores from two lakes near Thule. We can investigate various parameters within the lake sediment (for example, the amount of organic material, the size of the sediment, etc) and make inferences about climate of the past. We took cores from two very different lakes in close proximity. The first lake was fed by a large inflow, and therefore has likely experienced a high sedimentation rate throughout the Holocene; accordingly, our 1-m length corer wasn’t sufficient to reach the beginning of the sediment record. The second lake did not have an inflow, and therefore has likely experienced a low sedimentation rate. The cores we collected from this lake were very short, suggesting that the entire Holocene history of the lake is preserved in only a few tens of cm of sediment. We brought home four cores in all, and will analyze and interpret them over the coming year.

Lake_Coring
Our faithful boat, “Cookie Monster”, sitting in front of the first lake we cored.

To get an idea of the timing of ice margin retreat, we collected samples for cosmogenic nuclide dating in many areas across the landscape near Thule. When an ice sheet retreats (like at the end of the last ice age), it drops large boulders on the landscape. As these boulders are uncovered, they become exposed to the sky and are bombarded by high-energy cosmic radiation from outside our solar system; this high energy radiation causes the formation of beryllium-10, a rare isotope that is not formed through other mechanisms on Earth’s surface. If we know the rate at which beryllium-10 is produced in rocks (only about 5 atoms per gram of quartz per year), and we can quantify the present-day abundance of beryllium-10, we can calculate the time since exposure (i.e. the time that the ice margin last retreated from this area). During our last week in Greenland, we sampled the tops of ~25 large boulders, spread across the land surface. We’ll use this data to determine the timing, and maybe even the rate, of ice sheet retreat at the end of the last ice age.

Cosmo_Sampling
Erich samples the top of a large boulder for beryllium-10 analysis.

Finally, our third mission was to collect samples for radiocarbon dating, which allows us to determine the age of fossilized organic material. At several points during the Holocene, the climate warmed and the ice margin probably retreated upward from its present-day position. A receded ice sheet would have allowed vegetation to colonize the previously-covered areas. When climate cooled again, the ice margin would have re-advanced and covered the vegetated surface. We explored several areas of the ice sheet margin near Thule, and found fossilized organic material preserved in two locations. In some cases, this material was melting directly out of the ice. We’re guessing that this material may date to the Holocene Climatic Optimum or the Medieval Warm Period, and hopefully we’ll know by this fall or winter.

Fossil_Vegetation
Fossilized vegetation exposed from beneath the ice sheet margin.

All in all, we had a very successful week of work along the Thule margin. We also took some time for fun. On my birthday (July 17th), Erich took me to “D-Launch”, an abandoned missile launch silo on Thule Air Base. Most of the infrastructure is underground, in the permafrost zone, and so all of the rooms are filled halfway with ice. We had to climb down ladders with headlamps to get in, and totally creeped ourselves out while we poked around.

D-Launch
The view from D-Launch epitomizes Thule: beautiful, pristine Greenland coast with the unmistakable footprint of human warfare.

Alas, my 2011 field season has sadly come to an end. Thanks for following the progress of the Dartmouth Thule crew! We’ll continue to post updates as we get data.

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