Feeds:
Posts
Comments

Archive for the ‘Summit Station’ Category

This is a story about a very fun ride in an airplane.

On our flight from Kangerlussuaq to Summit, two very fortunate IGERT students (Steph and I) got the opportunity to sit on the flight deck of the LC-130 with the pilots. We had beautiful views of the landscape around Kangerlussuaq, the ice sheet margin, the crevassed zone, many supraglacial lakes, and ultimately hugely expansive white, flat ice. We also got to see the pilots in action and watch them take off, operate the controls during the flight, and land. Here are some photos from the flight of a lifetime:

IMGP0232
The flight deck of the LC-130. Best seats on the plane!

IMGP0190
Beautiful view of the ice sheet margin east of Kangerlussuaq.

IMGP0200
Cool folded ice layers near the ice sheet margin.

IMGP0203
Bright blue supra-glacial lakes near the ice sheet margin.

Advertisements

Read Full Post »

I arrived at Summit Station on July 13th, while traveling with the
Joint Science and Education Program (JSEP) for a short visit to the
camp. When we arrived, Summit Station had been experiencing above
freezing temperatures for multiple days prior to our arrival and a
melt layer formed on the near surface snow. I have been studying the
physical properties of the top layers of the ice, the firn, at Summit
and NEEM for my Ph.D. research. Recently, I have been focused on the
melt layers present in both firn cores because they occur very
infrequently. At Summit, there is only one other melt layer besides
the melt layer from this past week and this previous melt layer dates
to 1889.

The most interesting part of being at Summit Station just after a melt
event had occurred, is that the melt layer formation process could be
observed. When studying a firn core, there is only a small cross
section of the firn column that can be examined, which makes it hard
to understand how the melt layer formed and how evenly distributed it
is. Studying snow pits at Summit, including the recent melt layer,
presents a unique opportunity for us to understand how previous melt
events occurred. While at Summit density, stratigraphy, and
permeability measurements have been taken and samples will also be
brought back to the laboratory at Dartmouth, which will give us a clue
about melt layers in the past.

Read Full Post »

IGERT's at GISP2 Ice Core borehole

A metal cylinder protrudes from the Greenland Ice Sheet. An IGERT photo opportunity?

Absolutely, considering this metal cylinder changed how humanity views its production of CO2, nitrous oxide, sulfuric and nitric acids, CFC’s and other “greenhouse” gases (U. New Hampshire).

Prior to being a year-round research station, Summit Camp was the drilling site of the Greenland Ice Coring Project (GISP2). Drilled from 1989—1993, GISP2 is the deepest (3053.44 meters) and longest ice core record (>100,000 years) in the northern hemisphere.

The GISP2 ice-core record provides a continuous and detailed record of fluctuations in accumulation and climate variability over central Greenland. The GISP2 ice core, in conjunction with the GRIP deep ice core, revealed that exceptionally large climate changes (more than 20° C warming) can occur over much shorter time periods (5 to 40 years) than previously suspected (Cuffey et al., 1995)

In total, forty-two types of measurements composed the GISP2 deep drilling effort. The borehole, what remains after the conclusion of drilling, is filled with a fluid that keeps the borehole stable/open. The borehole can then be monitored via temperature-logging. The current metal casing may be in need of repair in order to keep the borehole available for future logging. Hopefully the National Science Foundation can find a way to maintain the GISP2 borehole, keeping the historic ice core borehole available for future measurements.

Cuffey, et al., “Large Arctic Temperature Change at the Wisconsin-Holocene Glacial Transition”  Science, Vol. 270, No. 5235, pp. 455-458, Oct. 20th 1995

Read Full Post »

At Summit Station we used snowpit stratigraphy (SS) in the backlit snowpit to investigate the characteristics of the past ~2 years of snow accumulation.

What is snowpit stratigraphy?

SS is the study of the layers (thickness, snow crystal structure, density, and porosity) and the depositional characteristics of snow.  The lighter vs. darker layers is the easiest difference to observe in the SS; this difference is also the most important because it allows for the identification of yearly snowfall.  Summer layers appear lighter and larger, due to larger snow crystals and more snow falling in summer (weird!), and winter layers look darker and thinner, due to smaller crystals, less falling snow, and higher winds in winter (see image below).

Why is snowpit stratigraphy important?

SS was the first method identifying annual layers of snow accumulation on ice sheets.  Additionally, it showed that these features are preserved as time passes.  This discovery led to modern ice core science.

To read more check out these papers:

1) https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B_MsC9DXUDH1Y2ZlYjQ2ZjgtMzExOC00MjQ3LWE3NTYtYzZjZDQ4ODAyMzA5&hl=en_US

2) https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B_MsC9DXUDH1YWIwZTBhODYtYTliZi00MThkLWIyOWQtOTAxZDUxZWI2MTk1&hl=en_US

Thomas Overly in the backlit pit at Summit Station

Read Full Post »

The iisPACS group (Isotopic Investigation of Sea-ice and Precipitation in the Arctic Climate System), led by Xiahong Feng and Eric Posmentier of Dartmouth College, and John Burkhart of the Norwegian Institute for Air Research. The group is researching how sea ice extent affects sea surface evaporation and land precipitation in Arctic regions, and how this effect impacts the Arctic Climate System. In order to attempt to answer this question, we precipitation samples will be collected at various sites across the Arctic and measure the oxygen and hydrogen isotopic composition of the water. These isotopic measurements will be combined with weather information, sea ice satellite observations, and numerical models to quantify how the amount of land precipitation is regulated by sea ice extent.

One of the new stations we are setting up is located at Summit. With all precipitation falling as snow in this extreme environment, a challenge is presented in collecting these samples by only collecting the falling snow and not blowing snow, along with the sampler being able to withstand the adverse weather conditions. Our research assistant, Anthony Faiia, designed a snow sampler that will help to eliminate these challenges. While at Summit, we helped set up the sampler and solved any issues. Let the snow sampling begin!

Read Full Post »

What is Fukushima?

In case you’ve been living under a rock or on top of an ice sheet, Fukushima radiation, refers to the release of nuclear radiation from the Fukushima I Nuclear Power Plant in Japan starting on March 11, 2011.

The release of radiation was caused by one of the world’s largest ever recorded earthquakes, a 9.0 magnitude, that struck off the east coast of Japan. The earthquake created a large tsunami up to 133 ft in parts of Japan.  The combination of the huge amount of shaking and the inundation and power of the tsunami wave lead to the eventual meltdown of 3 of 6 reactors at Fukushima I and the release of large amounts of radiation from the power plant (See Wikipedia and the NY Times).

So what does Fukushima have to do with Summit, Greenland?

Ice core scientists use atmospheric events such as major volcanic eruptions to confirm the age of ice cores at specific depths.  Beta radiation from upper atmosphere nuclear weapon testing during the 1950s and 1960s appear in Greenland ice cores (one such core was drilled right here at Summit, GISP2).  Will radiation from the Fukushima disaster be deposited in the snowfall of central Greenland?

Dartmouth’s own Erich Osterberg, Research Assistant Professor in Dartmouth College’s Earth Sciences Department, was recently awarded a NSF Rapid Research and Response (RAPID) grant to study the impacts of the Fukushima Nuclear power plant disaster.  IGERT student here at Summit Camp are assisting with the collection of snow, which will eventually be tested for the presence of cesium, Cs137.

What evidence is there that radiation from Japan got all the way to Summit?

After the Fukushima disaster began, air masses (possibly containing radiation) from multiple different elevations (red=low, blue=medium, green=high) moved eastward over Greenland, between 2 and 3 weeks after the disaster started according to two different sets of meterological data available from NOAA’s Air Resources Laboratory and their HYSPLIT model.

Now that we know what Fukushima is, what is has to do with the Greenland Ice sheet, and how it got here, lets talk about how we collected samples to test if radiation from Fukushima actually accumulated in detectable amounts in the snow pack.

Willy Wonka and the Chocolate Factory version 2.0 – White Umpa Lumpas on Ice

First we shipped three huge ice core boxes full of 45 4L Nalgene bottles from Hanover, NH all the way to Summit with the 109th Air National Guard unit. Additionally, Thomas Overly, one of the IGERTs who recently completed the 1500km traverse from Thule, Greenland to Summit and back again in May and June had left smaller sampling bottles for us to use for the first sampling procedure. The next step was to dig a huge snow pit (7m long x 2m deep x 1.5 m wide – shown below), which contained two of the sampling locations, and one other pit ~100m away (2m long x 2m deep x 1.5m wide), containing the third replicate.

Thomas, Ben, and Ian digging the big pit

Once the pit was dug, we had the immense pleasure of donning white clean suits and gloves (so as not to contaminate the samples – see Sam and I below) – and transforming into snow umpa lumpas.  And FYI wearing straight white was freezing – super high albedo.

Two sampling procedures were conducted at each site.  The first set of samples was for isotopes and anions; 125mL of snow was sampled once from each 5cm layer from the surface to 1m depth (see Sam and I in action below).  Next we used the 4L nalgenes to sample each 10cm layer three times from the surface to 50cm. In addition to sampling once with the 4Ls, we brought the bottles inside, put them into the sink (we were on dish duty so it was no big deal), and melted the snow in bottles.  We then consolidated the water from the different 10cm increments and different sampling locations into one of the three bottles. Once we had two empty containers for each 10cm increment we went back out to the pits and resampled the layers, so as to increase our total amount of water collected.  The huge amounts of water from each layer and pit was needed so as to detect the very low levels of radiation, which may or may not be present in the snow at Summit.

You may ask why we only sampled the top 50cm with the 4L bottles – well the answer is that the annual precipitation at Summit is approximately 60cm, therefore sampling the top 50cm is more than enough to capture the precipitation that may contain the radioactive fallout from Fukushima.

Marcus Welker and Sam Fey digging sampling for Fukushima fallout

Overall the sampling for Fukushima was a huge success.  In addition to our sampling for radioactive fallout, we observed the stratigraphy of the first ~2m, took a firn sample, and conducted permeability and density tests.  Stay tuned for the results of this work.

Read Full Post »

Team IGERT helped Kaitlin collect all her data for a snow pit on summit — permeability, density, and crystal size. To find out more about the process, please view our mini documentary.

Read Full Post »

« Newer Posts - Older Posts »