Kangerlussuaq Field School 2012

By Group Four: Sydney Barnes, Aggu Broberg, Malene Olesen, Nivi Knudsen

Is the Greenlandic Ice Sheet Melting?

Group Results

The bamboo sticks on the ice sheetMoraines and lakes on the ice sheetWatson River MeasurementsSprintt Data

Bamboo sticks on the Ice Sheet (Point 660)

Asa Rennermalm – Geographer from Rutgers University Asa drills holes in the ice and places bamboo sticks in them, and by periodically checking the sticks, she can measure how much the ice melts at point 660 over a given period of time.

Moraines A moraine is an accumulation of soil, rocks, and

otherglacial debris. They are formed where the

glaciers meet the land. They are easily identified because they

appear out of place on the landscape.

The Moraine that Asa showed usYou used to be able to see the ice sheet from

the road, butit has receded behind the moraine. This shows

that theglaciers are slowly receding over the years. If

you look atGoogle Earth, you can also see that the

meltwater lakes onthe other side of the moraine have increased in

size.

Meltwater Lakes on the iceImages from Google mapsshow an increase in thenumber of meltwater lakeson the Greenlandic ice sheets.

Month Width of melt zone (km)

June 2001 15June 2002 25June 2003 50Table 1. Data from SPRINTT

Watson River Sediment Discharge Measurements Our experiment was designed to find the

amount of Sediment (in kg) that flows out of the Watson

River a day.Group 4’s experiment failed because our side of

the riverhad much rougher water that covered our

indicators. However we were able to take the data from

group 5.

Watson River (Cont.) We found that the water travels 102 meters in 14.3 secondsover a 40 m2 cross section. And it had a velocity of 7.13 m3/s. So, if you multiply the velocity by the cross sectionyou get the discharge of the river, which is 285 m3/s. Wewere told that there is 2 kg/m3 of sediment in WatsonRiver, therefore there is 570.62 kg of sediment flowing out everysecond. If you multiply that number by the number of secondsin a year (excluding the seconds that the river should be frozenand therefore not discharging sediment, 86400 seconds) Youfind that there is roughly 49,301,568 kg of sediment dischargedby Watson River every year.

Sprintt Data

This data showed a decrease of 4% in total area of the Greenland ice sheet.

Mass balance = accumulation – ablation

Jakobshavn Glacier shrunk 8 miles and moved 113 feet per day in the last 5 years. Average speed of moving glaciers in the world is 1 foot.

Type of change Area in M3 Percentage of total area

Decreased a lot 96,733 5%Decreased a little 225,711 12%Remained unchanged

1,281,715 70%

Increased a little 217,650 12%Increased a lot 12,092 1%Table 2. Data from SPRINTT

What will happen if the ice sheet melts?the ocean will rise up to 7 meters and some of

thecities/countries will be Covered in ocean.If both Greenland and Antarctica melts down

the waterWill rise up to 80 meters.Greenland will rise and when the ice sheet

melts Greenlandwill experience earthquakes when the ice sheet

is one.

So, is it melting?Although from our data it would appear that you

could saythe Greenland ice sheet is melting. However

this cannot besaid for sure because all the data we have is

only outflow.You would need inflow data as well to say for

sure whetheror not the ice sheet is melting.

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Photo Credit:Dana Cucci