As part of the Long Term Ecological Research (LTER) project in the McMurdo Dry Valleys of Antarctica, a systematic sampling program has been undertaken to monitor glacial mass balance and meltwater flow. This data package includes snow density measurements determined at each stake with snow present on glaciers in Taylor Valley (Canada, Commonwealth, Howard, and Taylor) and Miers Valley (Adams), all of which are located in the McMurdo Dry Valleys of Antarctica. Included here for each stake are the snow thickness and density for each layer and the average density for each pit. Most measurements began during the 93-94 field season. Adams measurements were established during the 14-15 field season. Measurements are ongoing for Adams, Commonwealth, and Howard glaciers. Monitoring the changes in these measurements over time provides a record of mass balance, and aids in determining the role of glaciers in the polar hydrologic cycle.
The goal of each summer season is to take measurements in early spring (Oct/Nov) and late summer (late January). This provides a measure of seasonal winter/summer changes of glacier mass.
The average snowpack density is determined by digging a snowpit near each of the stakes that has any amount of snow present on the surface. The snowpit is dug to the surface of the ice for stakes in the ablation zone and to depth of the previous year's snow surface in the accumulation zone. The different layers in the snowpit are identified in the field. The thickness of each layer is measured and a sample is collected using a 100cm3 metal sampler. Excess snow is removed by a brush and the contents are placed in a pre-weighed bag. The weight is measured using a spring scale. Note about measurement timing: The goal of each summer season is to take measurements in early spring (Oct/Nov) and late summer (late January). This provides a measure of seasonal winter/summer changes of glacier mass. In some circumstances we have the opportunity or need to measure the glaciers in mid-season (Dec). View the dates the measurements were made at the following URL: http://www.mcmlter.org/data/glaciers/timing/snowdates.pdf A Note about Stake names: A stake with an H or V indicates a stake along the ice cliff that forms the boundary of the glacier terminus. An H is a horizontal stake placed into the vertical wall of the glacier terminus, and V is a stake placed into the ice apron at the base of the ice cliff. The vertical stakes were installed to support the horizontal stakes and provide a nearby measure of ablation for a surface with a much different slope.