Summary
The day started with a SKYPE session with Andreas Mikkelsen of Copenhagen University. He explained to the students how to measure river discharge rate (flux) and how that relates to glacier melt. The students then went out to the river and made measurements using simple methods: students dropped a branch in the river and timed how long it traveled a known distance. The distances were determined using GPS coordinates.
Each Group's responsibilities for the day are:
- Group 1: Measure flow rate on the right side of the river over a short (bridge-width) distance.
- Group 2: Measure flow rate on the left side of the river over a short (bridge-width) distance.
- Group 3: Video journal of Watson River experiments.
- Group 4: Measure flow rate on right side of the river over a long distance. GPS measurements required.
- Group 5: Measure flow rate on the left side of the river over a long distance. GPS measurements required. This group was also responsible for the weather measurements for the day.
Pictures from Today's Activities
Students on the bridge conducting flow rate experiments
Group 5's Nivi (Grl) and Dana (US) collect branches for flow rate experiments. Students dropped the branches in the river and measured the speed.
Bikke and Malou (Grl) taking flow rate measurements.
Results
Watson River Flow Rate Experiments
Groups 1,2,4 and 5 all contributed to the Watson River Flow Rate data. Below is Group 5's analysis of all of the data. A pdf. document is linked below which includes the data from all groups.
Group 5 Watson River Analysis We went down to the bridge to measure the water discharge in the Watson River. To find out the discharge, we had to first calculate the flow rate by measuring the time it took for a branch to travel 102 meters down the river. We did several trials of dropping the plant branch off the bridge and allowing it to travel to the same point in the river. We averaged the times we recorded which resulted in 14.3 seconds. Knowing the time and the distance allowed us to find out the velocity of the river using the equation velocity= distance/ time. We calculated the velocity to be 7,132867133 meters per second. Then we used the equation discharge= velocity times cross section area of the river. The result was 285.31 cubic meters per second. Next we wanted to know the sediment transport from the Watson River in one day. To determine this we multiplied our water flow rate by the amount of kilograms of sediment discharged in one cubic meter, which was 2 kg/ cubic meters. By doing this we calculated how many kilograms are discharged in one second. Then we multiplied this number by the amount of seconds in one day and found that 49301568 kilograms of sediment is discharged from Watson River over a 24 hour period.
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Group 3's Journaling Video of Watson River Experiments
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Educator Notes about this experiment
Kasper Busk spent about 30 minutes going over the data with the students illustrating to them that their data, with all its estimations, is fairly close to what the scientists predict!
Shelly Hynes followed up with a discussion of error. We discussed whether our data was precise, accurate, none or both and why knowing the difference was important. Since students took an average of the data we also discussed how to calculate a standard deviation and why its important to report error in your data.
Today's Weather at Watson River by Group 5
Wind velocity: 1,6 m/sec.
Temperature: 12,9 C°
Relative humidity: 62%
Absolute humidity: 6,2
Wind: 1,9 – 2,2 m/sec
Dew point: 44 C°
Wind chill 12,7 C°
Light intensity: 2198.18 lux
Student Blogs
Malene Rasmussen, Qaqortoq, Greenland
Malene at Russell Glacier
My name is Malene Rasmussen and I am 17 years old, I come from South Greenland and live in a town called Qaqortoq. I go to school in GU Qaqortoq and just finished my fist year. I love geography and looking at different kinds of rocks and mountains, and I want to be a geologist and work in Greenland. When I heard of the Kangerlussuaq science field school I decided to send an application and rote why I wanted to go and got in.
Today's Activities The fist thing we did when we met at 8:00 am was to get some information on what we were going to do today, and after that Andreas Bech Mikkelsen a student from the Copenhagen University gave a videoconference on Skype about his project about discharge and sediment transport in Watson river in Kangerlussuaq fjord, he makes measurements to get data about the Greenlandic ice, to qualify the role of the melting and to get a better understanding of the process in the glaciers and melt water rivers. To measure how much sediment that is transported out of the glacial rivers we have to find the cross-sectional area of the river, the turbidity (concentration of sediments in the water) and how much water there’s coming out of the river (m3/s.). The reason we measure the concentration of sediments in the water is that the more sediments that’s in the water, the more discharge there is. After the videoconference we had an exercise down at the Watson river, to measure the water discharge with the float method and calculate the sediment transport. When we got back after the exercise my group (group 3) had and interview with Andreas to explain a little more about his project here in Greenland and we made a video out of it. We also made a video about the groups that made the exercises down at the Watson river.
Maeve McCormick, Boise, Idaho
Maeve McCormick, Boise, Idaho
The Activity of the Day for July 3, 2012: Discharge Measurements and Sediment Transport in the Watson River & Kangerlussuaq Fjord
Today, we spent time in our individual groups measuring the discharge of the Watson River into the Kangerlussuaq Fjord. Groups one and two took short-distance measurements from the North and South ends of the bridge spanning the river, and groups four and five took long-distance measurements from opposite sides of the shore. My group (group three) took video footage of the other groups during their testing, and we interviewed Andreas Mikkelson, whose research we had heard about earlier in the day. Our discussion with Andreas was very interesting and enjoyable; he offered many insights into his field of study and its applications in the “real world”. Later in the day, we logged on to the SPRINTT website and participated in an interactive lesson about the Greenlandic ice sheet and its numerous glaciers.
Some new knowledge I gained from Andreas’ lecture this morning includes the number of variables upon which a glacier’s water balance is dependent. General factors such as precipitation and melt water were expected, but I did not even consider the role of evaporation or sublimation in the maintenance of the water balance. Additionally, the equation for calculating the water balance (Precipitation + Evaporation + Runoff + Change in Storage = 0) was new to me. After my discussion with the Danes (Cecilie, Charlotte, and Fie) at lunch, I found it interesting how we (Americans) often take the size of our country for granted. Distances between cities, landmarks, and other locations within the US seem very different to people from other countries (such as Greenland or Denmark) relative to those that they are used to considering. A two hour drive from Boise might get you to a smaller town to the north or south, whereas in Denmark, it might get you from one end of the country to another! It’s interesting to consider such things from a different perspective than that to which one is accustomed.