Coring for Answers
It’s no secret that the word’s glaciers are shrinking. And nowhere is this more apparent than at one of the world’s most studied glaciers, McCall Glacier in the Arctic National Wildlife Refuge (ANWR) in Alaska. With its long history of data, McCall Glacier is the perfect location for studying everything from the cause of glacial retreat to how Arctic climate and terrestrial ecology have changed over the past several centuries.
Since 2003 Matt Nolan, a professor at the University of Alaska Fairbanks’s Institute of Northern Engineering, has organized a team of international researchers that descend on the glacier every summer to collect ice cores and other data.
“Our field research is geared towards measuring everything which may change over time, including surface mass balance, ice volume, ice temperature, ice velocities, bed properties, ice cores, subsurface ice accumulation, surface albedo, and local weather,” Nolan wrote on his blog.
A Popular Place Among Researchers
Studies at McCall Glacier began in 1957, just a few years before ANWR was established. Nolan’s work builds upon this more than 50-year history of data collection by incorporating new technologies and tapping international resources. And with new funding from the National Science Foundation (NSF) and the U.S. Fish and Wildlife Service (USFWS), the collaborative research effort will continue well through 2013.
“What makes McCall unique at this point has as much to do with the fact that this is one of the few glaciers in the state that has any long-term scientific record as it does with its role in landscape dynamics,” Nolan explained. “There may be four or five glaciers that have a similar history, but McCall has by far the highest density of instrumentation studies. It’s one of the most thoroughly studied glaciers in Alaska.”
Nolan’s NSF project focuses on analysis of a deep ice core collected in 2008 to understand climate variations over the past 300 years. The USFWS-sponsored project explores how shrinking glaciers may affect fish and bird ecosystems downstream. Both fish and birds migrate to these rare glaciated watersheds due to the abundance of freshwater created by glacier melt.
A Snowy Summer at McCall
The 2010 field season was a long haul with the first portion occurring in April and May, followed by a concluding visit in August. In the spring, Nolan and participating researchers gathered essential time series baseline data, such as how much snow fell during the winter and basic weather data.
The team also hand-augered cores about 5-10 meters deep to measure how much summer meltwater drips into the snowpack and refreezes. This process of internal accumulation is one way glaciers grow from year to year. And despite being such an important process, it’s one that is poorly understood because it is so difficult to observe.
“What we’re trying to do is track layers as they evolve over time. We started shallow coring in 2008 and we’re tracking the 2008 snow layer as it’s gradually buried by later year snow to see how much change we get,” Nolan explained. Cores initially drilled two years ago are revisited annually.
During the return trip in August, a variety of remote sensing mapping data were collected using plane-mounted LiDAR technology and other tools. The LiDAR measurements will be used to create detailed topographic maps of McCall and surrounding glaciers which will be used to measure how much ice has disappeared.
Mayor of McCall
Aside from drilling cores and collecting data, Nolan sets up and manages the base camp all the researchers call home while stationed on McCall Glacier for weeks or months at a time. And since there aren’t any stores or nearby villages to buy forgotten items, Nolan either brings or stores everything a self-sustaining tent village full of researchers might need.
“We have to set up a small city every time that has all the major functions of a regular civilization—a place to sleep, a place to work, a place to eat, power, water and electricity. And basically I’m the mayor,” Nolan said.
Doing anything on McCall Glacier really depends on the weather. Conditions can range from warm days where it’s almost too hot to get much work done to days when 100-mile-per-hour blizzards bring work to a standstill. When the weather is agreeable, work at the McCall Glacier camp gets started bright and early with researchers grabbing a quick breakfast and gearing up for a day in the elements. By 9:00 a.m. folks are on the snow machine and on their way to visit data collection sites to core, service equipment, take GPS surveys, etc.
Nolan usually likes to keep the work day to 10-12 hours so that everyone can meet for a hot dinner around 7:00 or 8:00 p.m. Once dinner is finished people have a few hours to process data, prepare for the next day, chat and relax in front of a DVD. For Nolan, the research camp is extra homey because his wife Kristin and son Turner participate in the arctic adventure. As camp manager, Kristin makes sure everyone stays well-fed and healthy, and as camp clown, Turner makes sure people have a smile on their faces.
Back Home in the Lab
While a lot of exciting work takes place in the field, a great deal of analysis occurs when the ice cores are shipped back to the lab. The ice cores are cut into smaller pieces and positioned into a hopper where they are melted. The melt water is then passed through several instruments, such as mass spectrometers, to analyze more than 40 different chemical compounds that say a lot about the characteristics of the surrounding environment.
“The chemical compounds we’re looking for can range from simple things like soot from forests fires to lead and cadmium pollutants. We look at stable isotopes in the water and oxygen,” he said. “We also look at pollen. Airborne pollen plumes in from the surrounding area and gets trapped in the snow and ice. By looking at the variations in the pollen types we can look at changes in the ecosystem over time."
Now that the 2010 field season is under his belt, Nolan is already looking ahead to the 2011 season, which starts in May. The McCall team will continue to collect baseline data on the glacier, maintain equipment and analyze the 2008 ice cores to better understand climate dynamics affecting the eastern Arctic.
For more information about Matt Nolan and his work at McCall Glacier, visit his web site, which includes daily posts and field pictures: http://www.drmattnolan.org/mccall/index.htm —Alicia Clarke