SnowMicroPen
The SnowMicroPen is an instrument co-developed by Martin Schneebeli
of the Swiss Federal Institute for
Snow and Avalanche Research (SFISAR) and Jerry Johnson of
the Cold Regions Research and
Engineering Laboratory. This instrument is a constant-speed
probe that is driven through the snow, providing the user with
250 hardness measurements per mm resulting in extremely detailed
snow profile and snow structure information.
This instrument has evolved over the last 40 years. The
original resistograph was developed by Charles Bradley in the
1960s while he was working as a Professor in the Department of
Earth Sciences at Montana State University. In the mid-1980s,
Bob Brown (Professor in Civil Engineering at MSU) and graduate
student Tim Dowd enhanced the idea of Bradley's resistograph to
include a probe with a load cell and a microprocessor.
The resulting "Digital Resistograph" was further enhanced
in the late-1980s by Karl Birkeland while he was working on his
MS research at MSU. Cooperatively, Schneebeli and Johnson
worked through many existing technical problems to come up with
the current, much-improved instrument. Given the history
of this instrument, the Forest Service National Avalanche Center
and Montana State University are excited to be able to test and
use the new and improved "SnowMicroPen".
In an agreement arranged by Montana
State University Techlink, the Forest Service National Avalanche
Center cooperated with SFISAR, CRREL, Montana State University,
and CF Electronics to obtain and a SnowMicroPen during the 2000/2001
season, and has used one since that time.
The high resolution signal of the SnowMicroPen allows the identification
of not only the hardness of specific layers, but also the grain
types as well as calculations of some of the mechanics of the
snow structure. Because many measurements can be conducted relatively
rapidly, the National Avalanche Center, and SFISAR, have been
using the SnowMicroPen for studies of spatial variability. A number of publications
utilizing the SnowMicroPen are listed below the photographs.
 |
| Close
up view of one of the first SnowMicroPens, Switzerland, 2000 |
|
Demonstrating the use of the SnowMicroPen
in Montana, 2001
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Utilizing the SnowMicroPen for spatial variability
research, Montana, 2002
Technical papers using the SnowMicroPen
Birkeland, K., K. Kronholm, and S. Logan. 2004. A comparison
of the spatal structure of the penetration resistance of snow layers
in two different snow climates. Proceedings of the International
Symposium on Snow Monitoring and Avalanches, Manali, India, in
press. [Article]
Birkeland, K., K. Kronholm, M. Schneebeli, and C. Pielemeier.
2004. Changes in the shear strength and micro-penetration hardness
of a buried surface hoar layer. Annals of Glaciology 38, 223-228.
[Abstract] [Article]
Johnson, J., and M. Schneebeli. 1999. Characterizing
the microstructural and micromechanical properties of snow. Cold
Reg. Sci. Tech. 30(1-3), 91-100.
Pielmeier, C. and M. Schneebeli. In press. Snow
stratigraphy measured by snow hardness and compared to surface section
images. Cold Reg. Sci. Tech.
Pielmeier, C., M. Schneebeli, and T. Stucki. 2001. Snow
texture: a comparison of empirical versus simulated texture index
for alpine snow. Ann. Glaciol. 32, 7-13.
Schneebeli, M., C. Pielmeier, and J. Johnson. 1999.
Measuring snow microstructure and hardness using a high resolution
penetrometer. Cold Reg. Sci. Tech. 30(1-3), 101-114.