Snow Pack Analyser, March Snow Pack Analyser SPA

Snow Pack Analyser, March Contents History Principle of Measurement SPA Snow Parameters SPA System Sensor Setups Examples Summary

Snow Pack Analyser, March History Snowpower: EU research project –FZK Karlsruhe (Germany) –SLF Davos (Switzerland) –KTH Stockholm (Sweden) –Hydro-Quebec (Canada) –INRS (Canada) –Sommer (Austria) Sensor Development and Improvement Snow Pack Analyser SPA Test site Davos, SLF Test site Quebec, Hydro Quebec

Snow Pack Analyser, March Principle of measurement Three components of snow: ice, water and air Frequency dependence of dielectric constants Measuring of complex impedance at minimum two frequencies Estimation of the volume contents of the components Calculation of the density Calculation of SWE in combination with snow depth Ice Water Real part Imaginary part Frequency [Hz] Dielectric Constant

Snow Pack Analyser, March SPA Snow Parameters Snow density Snow water equivalent SWE Contents of ice and liquid water in snow Snow depth Snow temperatures (optional) –Profile –Ground –Surface

Snow Pack Analyser, March SPA System Sensor –Length between 3 and 10 m –Width of 6 cm Suspension –Sloping or horizontal installation –Displacement sensor Snow Depth Sensor –Transit-time measurement of ultrasonic pulse –Temperature compensation Measurement and control unit –Impedance analyser –Multiplexer for 1 to 4 cables –Calculation of snow parameters –RS 232 data output

Snow Pack Analyser, March Measurement and Control Unit Sensor 1 Sensor 2 Sensor 3 Sensor 4 Snow Depth Displacement Temperatures DC V RS 232 Output Data: Sensor Density - SWE - Liquid Water Content - Ice Content - Snow Depth - Temperatures SPA Snow Pack Analyser Input Data: Sensor Length - Top Level - Bottom Level

Snow Pack Analyser, March Common Setup Combination of sloping and horizontal sensors -> Snow parameters of integral snow cover -> Additional data at specific levels

Snow Pack Analyser, March Profile Setup Multiple horizontal sensors at defined levels -> Profile Information

Snow Pack Analyser, March Area Setup Star shaped installation of multiple sensors -> Data with high areal information -> Up to remote sensing pixel size

Snow Pack Analyser, March SPA Installation Combination of sloping and horizontal sensors Suspension springs and winches

Snow Pack Analyser, March Displacement ΔL of 10 cm -> 50 cm more Sensor in Snow Snow Mast Sensor ΔLΔL Snow Mast

Snow Pack Analyser, March Displacement Davos (Switzerland) - Sloping Sensor - 10 m

Snow Pack Analyser, March Davos Davos (Switzerland) – 2660 m

Snow Pack Analyser, March Davos Davos (Switzerland) – 2660 m

Snow Pack Analyser, March Davos 2006/2007 Davos (Switzerland) - Sloping Sensor - 10 m

Snow Pack Analyser, March Davos 2008/2009 Davos (Switzerland) - Sloping Sensors - 10 and 5 m

Snow Pack Analyser, March Davos 2008/2009 Davos (Switzerland) - Horizontal Sensors - 10 and 5 m

Snow Pack Analyser, March Davos 2008/2009 Davos (Switzerland) - Horizontal Sensors - 10 and 5 m

Snow Pack Analyser, March Korsvattnet Korsvattnet (Sweden) – 700 m

Snow Pack Analyser, March Korsvattnet Korsvattnet (Sweden) – 700 m

Snow Pack Analyser, March Korsvattnet 2008/2009 Korsvattnet (Sweden) - Horizontal Sensor - 5 m Point A Increase of liquid water content No changes in snow depth and snow pillow -> Begin of melting process Point B At about 7-8 % liquid water content Decrease of SWE on snow pillow -> Begin of run-off A B

Snow Pack Analyser, March Run-Off Forecast A B C Point A Snow compression SWE constant Point B Run-off starts SWE decreases Point C Significant increase of liquid water content prior to the start of run-off (point B) Davos (Switzerland) - Sloping Sensor - 10 m

Snow Pack Analyser, March Hindelang Hindelang (Germany) – 980 m

Snow Pack Analyser, March Snow Cover with Ice Layers Hindelang (Germany) – Sloping Sensor – 5 m Point A SPA and snow pillow show similar data Point B Appearance of ice layers in snow pack Point C Snow depth stays constant Snow pillow fluctuates SPA does not fluctuate A BC

Snow Pack Analyser, March Foehn Event Hindelang (Germany) – Sloping Sensor – 5 m Point A Temperature > 0°C Slight increase of snow density and liquid water content Point B Foehn event causes sudden increase of liquid water content above saturation of snow pack -> run-off situation -> risk of wet snow avalanches A B

Snow Pack Analyser, March Daily Variation of Liquid Water Hindelang (Germany) – Horizontal Sensor – 5 m Point A High liquid water content Points B Slight increase of liquid water above saturation causes sudden rise of liquid water. This liquid water is reduced by run-off. -> Buffer behavior of snow regarding to liquid water A B

Snow Pack Analyser, March Daily Variation of Liquid Water Hindelang (Germany) – Horizontal Sensor – 5 m Point A Maximum of air temperature Point B Begin of increasing water content -> Shift between air temperature and liquid water content A B

Snow Pack Analyser, March Sylvensteinspeicher Sylvensteinspeicher (Germany) – 780 m

Snow Pack Analyser, March Sylvensteinspeicher 2009/2010 Sylvenstein (Germany) - Horizontal Sensor - 5 m Point A Increase of liquid water content No changes in SWE snow depth decreases -> Begin of melting process Point B At about 6 % liquid water content Decrease of SWE on snow pillow -> Begin of run-off A B

Snow Pack Analyser, March Installations Val de Aosta (Italy) Tauplitz (Austria)

Snow Pack Analyser, March Summary In-situ measurement of snow parameter –Liquid water content –Snow density –Snow water equivalent –Snow depth Specific setup of sensors –Integral snow pack –Profile data –High areal information Forecasting the start of water run-off Not influenced by ice layers Simple installation even at hillsides