Greenland Preparation I: Discharge measurement

This spring semester we began preparations for upcoming fieldwork on the Greenland Ice Sheet, supported by an NSF project in collaboration with Jason Gulley at USF. The goal of the project is to study the links between meltwater delivery to moulins (deep holes in the surface of the ice sheet), the evolution of conduit systems within the ice, and the sliding motion of the ice sheet. When meltwater reaches the base of the ice, it can lift the ice, reduce friction, and accelerate the sliding of the ice. However, models of the processes behind these links remain relatively poorly constrained by data. To examine these links in the field, we will measure water levels within the moulins, discharge within the meltwater streams that feed the moulins, and use GPS units to record the motion of the ice.

In preparation for work in Greenland this summer, we have been refining our protocols for discharge measurement within the meltwater streams. We will make these measurements by injecting known quantities of a harmless fluorescent dye (Rhodamine) and measuring concentrations of that dye downstream using field fluorometers.

Pumping dye into nalgene bottles for shipment to Greenland.
Pumping dye into nalgene bottles for shipment to Greenland.
Prototype pump setup for dye injection.
Prototype pump setup for dye injection.
Dye in a spring run where we were testing the measurement procedure.
Dye in a spring run where we were testing the measurement procedure.
Field fluorometers deployed in stream.
Field fluorometers deployed in stream.

 

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