1. Compact Probe for In-Situ Optical Snow Grain Size Stratigraphy

2. Snowmelt provides >75% of California’s water.
Mountain snow is the main water source for 60 million Americans.
Snowmelt sustains one billion people globally.
Snowpacks are rapidly changing.

3. Remote Sensing of Snow Snow Water Equivalent (SWE) Radar Microwave
SMAP, SCLP, Cryosat II, ERS 1 & 2, Sentinels
Microwave
SCLP, EOS Aqua, Envisat, SMOS, ERS 1 &2

4. Remote Sensing of Snow
SWE algorithms are limited by knowledge of grain size and understanding of the relation between signal and grain size variation.

5. Remote Sensing of Snow
There exists no ground instrument to provide large datasets of grain size stratigraphy.
Armstrong et. al., Annals of Glaciology, 17, 1993, “Snow depths and grain-size relationships with relevance for passive microwave studies”

6. Traditional Grain Size Measurements

7. Traditional Grain Size Measurement

8. Traditional Grain Size Measurement
Hand lens grain size estimation

9. Traditional Grain Size Measurement

10. Radiative transfer from hand lens
Painter et al., Journal of Glaciology 2007

11. Contact Spectroscopy Advantages Less subjective Repeatable Faster
Data applicable to remote sensing
Painter et al., Journal of Glaciology 2007

12. Spectral Profiler Probe
probe carrier body
drive tube
optical camera
spectral reflectance probe
nylon brush
aluminum sleeve
fiber optic to spectrometer
Spectral Profiler Probe
Send optics down hole
Lateral reflectance spectra
Fiber optic sends signal to surface
No snowpit!
Much faster than pit methods

13. Spectral Profiler Probe Hardware
optical inspection camera
spectral reflectance probe
nylon brush
In-bore light source

14. Spectral Profiler Probe Hardware
fiber optic to spectrometer
base plate
aluminum sleeve
drive tube
reflectance probe
clamp
Spectral Profiler Probe Hardware

15. Field Testing probe stowed for transport Niwot Ridge, CO
Storm Peak Lab,
Steamboat Springs, CO

16. Storm Peak Lab Feb 2010 results

17. Faster, Smaller, Cheaper
Use discrete optics
Eliminate spectrometer, fiber optic, pre drilling
T measurement
~1cm dia. Probe
Algorithms for on-site grain size retrieval

18. Discrete Optics Concept Test
Re-processed spectral data using only 2 points

19. Discrete Optics Concept Test
Easy availability of LED and laser sources.
Wavelength (nm)
reflectance

20. NILU collaboration Collect data from ESA and NASA satellites
Concurrent with probe data
Develop improved algorithms for SWE
Test against ground measurements

21. The Future of Snow Science
All measurements from space
Need better retrieval algorithms
Must understand grain size affect on signals
Need large ground datasets to get there

22. supplemental

23. Acknowledgements Jennifer Petrzelka Ty Atkins Alex Arnsten
Ian McCubbin (Storm Peak Lab)
Gannet Hallar (Storm Peak Lab)
Part of this work was performed at the Jet Propulsion Laboratory/California Institute of Technology under contract from NASA.

24. Compact Probe for In-Situ Optical Snow Grain Size Stratigraphy
Daniel Berisford1, Noah Molotch1,2, Thomas H. Painter1, Michael Durand3
NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA
INSTAAR, University of Colorado, Boulder, CO
The Ohio State University, Columbus, OH
Presented at the American Geophysical Union fall meeting, San Francisco, CA. December 13, 2010

25. Contact Spectroscopy optical equivalent grain size
obtained by integrating absorption feature and comparing to RT model
Painter et al., 2007; Nolin and Dozier, 2000.

26. 2 configurations
In-bore
light
fiber light

27. Niwot Ridge April 2010 results

28. Field Testing
spectrometer
tarp to block sunlight

29. Field testing

32. Aluminum reflectance spectrum

33. Kapton tape reflectance spectrum