Researchers seek answers from Athabasca Glacier
Wednesday, Jul 29, 2015 03:08 pm
The ice surface crunches underfoot, with the top few centimetres softened by warm summer sun allowing our boot soles solid purchase.
After 45 minutes of walking up Athabasca Glacier, Dr. Jonathan Conway joins two men standing on the ice looking into the sky. Warren Helgason and Bruce Johnson are flying a kite.
They are doing so as part of a scientific research project being conducted by the University of Saskatchewan’s Centre for Hydrology under the direction of Canada Research Chair in Water Resources and Climate Change, Dr. John Pomeroy.
Over four weeks this summer, scientists monitored several instrument stations as part of a glacier melt/glacier weather research project, the scale of which has never before been conducted in the Canadian Rockies.
The colourful nylon kite, with baffles and a streaming tail, is secured by a cord to an ice climbing screw drilled into the glacier. Fitted with a pocket weather meter that measures wind speed, temperature, humidity and pressure, they’ve flown it as high as 200 metres above the glacier surface.
Above 30 metres, they learned, wind and weather readings don’t vary much. Below that 30 metre ceiling, conditions fluctuate considerably, mostly between 9 a.m. and 5 p.m. Using a kite to gather data costs a fraction and weighs considerably less than traditional large balloon profiling equipment that requires helium tanks and winches to operate.
“We can carry it in a backpack and it makes it possible for us to get a lot of information for not much money,” Conway said. “What we want to know is, what’s driving the wind and how does it impact the glacier’s melting? In terms of melt, the glacier has a large effect on the weather conditions. What sort of scale is that process occurring at and how do we put that in a climate model?”
Like the vast majority of glaciers worldwide, the Athabasca, the largest of six tongues of ice descending from the Columbia Icefield, and the icefield itself, are melting at an increasingly rapid rate. In the past 125 years, the Athabasca has receded more than 1.5 kilometres and lost half its volume. Currently, it’s losing 5.5 metres annually to melting.
The aim of this research is to quantify the local climate over, and energy inputs into, the Athabasca Glacier at a series of locations from its snout to further up-glacier. This work is part of a general study of changing cold regions in western and northern Canada where scientists are quantifying the impact of climate warming on water supply, ecosystems, weather extremes of drought and flood, and changing snow and ice.
“The Columbia Icefield and Athabasca Glacier are incredibly important indicators of climate warming and also influence all of these other systems because of their location at the triple point Crown of the Continent source for the Columbia, Saskatchewan and Athabasca rivers, and because of their great size,” Pomeroy said.
“This will help us calculate how fast the Columbia Icefield is melting and how much freshwater this is putting into the many rivers that have their headwaters there. It will also help us to estimate how much water might be available in the future as the icefield melts away.”
In addition to two stations established on the glacier last September, another station was erected for three weeks just beyond the glacier’s toe using highly sensitive SODAR - Sonic Detection And Ranging – to record wind speed and direction. Different frequencies recorded readings at different heights all the way up to 500 metres above ground.
Setting up and maintaining instrumented sites on glaciers is always challenging and a main reason relatively little science has been done on glaciers. The scope of this summer’s Athabasca project has previously only been pursued on a small scale in Austria and Iceland.
“The Athabasca is as good as it gets for a glacier – easy access by road, easy to walk onto,” Conway said. “But even 100 metres from the parking lot this site is still harder to maintain than any on the Prairies. Monitoring glaciers is significantly harder. Glaciers are always moving, always changing.”
Installing an instrument station involves drilling a hole into the ice and inserting a pole, which is then supported by guy wires or a tripod base capable of withstanding fierce winds. Various instruments are attached to record weather conditions. The setup must be adjusted regularly through the summer as melting ice lowers the platform.
Learning as much as possible about the melting rate of the Athabasca is important far beyond the Rockies. While the Athabasca ultimately flows to the Arctic Ocean, the less accessible Saskatchewan Glacier, descending from the Columbia Icefield a few kilometres to the south, eventually flows through the Prairies before reaching Lake Winnipeg.
The information gained from the Athabasca project is being combined with the U of S’s ongoing studies at Fortress Mountain and Marmot Creek in Kananaskis, and at Helen Creek and Peyto Glacier in Banff National Park on the impact that snow cover, snowmelt, rainfall, forests and water storage in ponds and in groundwater have on controlling the mountain climate and water supply.
Ultimately, this information helps scientists quantify and predict how water resources and climate currently function and how they will change in the Saskatchewan and Athabasca river basins – basins that are crucial to the population, environment and economy of western and northern Canada.
“Having the Athabasca Glacier to work on is important,” Pomeroy said. “The dramatic shrinkage of Peyto Glacier over recent decades has made it a less viable research site for us and a more difficult place to answer these detailed questions.
“Peyto Glacier has become so small that it has a limited feed of flowing ice from the Wapta Icefield and likely a reduced glacier cooling effect compared to the Athabasca downwind of the Columbia Icefield. So, contrasting the well-studied Peyto with the Athabasca is a way for us to learn much more about how these icefields maintain their glaciers.”
Research at the Kananaskis and Peyto sites is complemented by the extensive ice coverage at Columbia Icefields and the Athabasca Glacier. The Columbia and Athabasca reveal what the rest of the Rockies were like in the past, while the less glaciated Peyto or other non-glaciated sites show parts of what the Columbia and Athabasca environments might be like in the future as climate warming progresses.
The scientists hope to learn how icefields regulate their own climate by cooling the local air mass and interacting with the non-glaciated - and therefore warmer - valley bottom to essentially create their own weather.
“We wanted to better understand the mechanisms by which this occurs and how much this might affect the melt rate of the Athabasca Glacier,” Pomeroy said. “By better understanding this self-regulating climate we can understand how resistant it is to climate warming and as the glacier and icefield shrink start to estimate at what point this ‘resistance’ is no longer as effective.
“As the ice shrinks past that point, we can expect greatly accelerated melt rates and that would be a very serious tipping point for an alpine glacier and icefield.”
Gathering this info is not just valuable, but urgent. The hot 2014 summer combined with extremely low winter snowpacks and the already hot 2015 summer are accelerating melting, causing about 5.5 metres of melt off the Athabasca Glacier annually.
“These are generally accelerated glacier and snow melt rates compared to anything measured in the past,” Pomeroy said. “This is part of some long-term trends that are associated with atmospheric warming from increased greenhouse gas concentrations in the atmosphere that are due to human-caused greenhouse gas emissions. The localized cooling of the atmosphere over the Athabasca Glacier and others like it caused by contact with the ice can help in a small way to slow the glacier melt, but we need to understand how large the icefield and glacier will need to remain in the future so as to keep this cooling intact.
“This experiment will help us understand what the future threshold for rapid glacier melt might be. What size does an icefield need to be to keep this localized cooling effect intact?”