1. Combining GIS and GPS to Improve Our Understanding of the Spatial Distribution of Snow Water Equivalence Todd Ackerman Tyler Erickson Mark W. Williams Institute of Arctic and Alpine Research University of Colorado Boulder, Colorado

2. Overview Research goals Research goals Site description Site description Data collection Data collection Analysis Analysis

3. Why study snow? 75% of annual water supply in the western US 75% of annual water supply in the western US Catastrophic flooding Catastrophic flooding

4. Problems in Snow Hydrology In western US, SWE is measured once every 1,800 square miles In western US, SWE is measured once every 1,800 square miles Scaling: point measurements of SWE to regional and global scales Scaling: point measurements of SWE to regional and global scales

5. Research Goals Detailed data set for snow hydrology Detailed data set for snow hydrology Improvement of methods for estimating SWE in alpine basins Improvement of methods for estimating SWE in alpine basins Relationship of SWE to landscape type Relationship of SWE to landscape type

6. GIS Platforms Platforms  ArcInfo 7.0.2 Workstation for Solaris  ArcInfo 8.1 Desktop and Workstation for Windows NT Extensions Extensions  Spatial Analyst  Geostatistical Analyst

7. Green Lakes Valley 3,575 to 4,000 m 3,575 to 4,000 m 1,000 mm of precipitation 1,000 mm of precipitation 80% as snow 80% as snow UNESCO Biosphere Reserve UNESCO Biosphere Reserve LTER network site LTER network site

8. Surrounding Area

9. Access 25 km roundtrip 25 km roundtrip Tundra lab Tundra lab

10. Field Methods Snow Probes Snow Probes Snow Pits Snow Pits DEM DEM Landcover Landcover GPS GPS

11. Field Methods Snow Probes Snow Probes Snow Pits Snow Pits DEM DEM Landcover Landcover GPS GPS

12. Field Methods Snow Probes Snow Probes Snow Pits Snow Pits DEM DEM Landcover Landcover GPS GPS

13. Field Methods Snow Probes Snow Probes Snow Pits Snow Pits DEM DEM Landcover Landcover GPS GPS

14. Field Methods Snow Probes Snow Probes Snow Pits Snow Pits DEM DEM Landcover Landcover GPS GPS

15. GPS Comparison Trimble Pro XR Trimble Pro XR Garmin GPS-III Plus Garmin GPS-III Plus

16. GPS Comparison

17. Snow Depth Measurements

18. Kriging Geostatistical Analyst Geostatistical Analyst  Useful, flexible tool Caveats Caveats  Stationarity  Lower bound constraint

19. Kriging Results

20. Correlation of Snow Depth with Landscape Type Measured PointsInterpolated Points

21. Summary GIS technology allows us to conduct better snow surveys, and to analyze the results GIS technology allows us to conduct better snow surveys, and to analyze the results GPS: lighter, cheaper, happier GPS: lighter, cheaper, happier Kriging can be used to scale up the point measurement, but is currently a black box operation. Kriging can be used to scale up the point measurement, but is currently a black box operation.

22. Acknowledgements Students, field staff (especially Tim Bardsley), Matt Tomaszewski, and volunteers who have helped with the snow surveys over the years. Students, field staff (especially Tim Bardsley), Matt Tomaszewski, and volunteers who have helped with the snow surveys over the years. NSF EAR-9526875 (Hydrology) NSF EAR-9526875 (Hydrology) Army Research Office grant DAAH04-96-1-0033 Army Research Office grant DAAH04-96-1-0033 NASA-EOS NASA-EOS Mountain Research Station of INSTAAR and CU-Boulder Mountain Research Station of INSTAAR and CU-Boulder Ongoing maintenance and data access is funded by the NSF grants DEB 92-11776 and DEB 98-10218 Ongoing maintenance and data access is funded by the NSF grants DEB 92-11776 and DEB 98-10218

23. Further Information Niwot LTER (http://culter.colorado.edu) Niwot LTER (http://culter.colorado.edu) INSTAAR (http://ekman.colorado.edu) INSTAAR (http://ekman.colorado.edu) TundraCam (http://tundracam.colorado.edu) TundraCam (http://tundracam.colorado.edu)