1. Snowmelt Modeling using UEB and GIS
By You Jinsheng
GIS in WATER RESOURCES

2. OBJECTIVE
Develop techniques for the representation and parameterization of subgrid and distributed snow processes within snowmelt models.
Collect data for Green Lake Valley Watershed in Colorado
Snowmelt process and distribution modeling in UEB Model and SnowGRID model

3. PROJECTIVE OUTLINE
Calibration and validation of the distribution snowmelt model in study watersheds
Reformulation of the point energy and snowmelt model to account for sub-grid variability through use of depletion curves
Development of depletion curves for area typical of broad scale elevation model elements, establish relationship between depletion curve and digital elevation data. Quantify scale dependence of depletion curves
Relationship to topography and scale dependence together comprise the guidance to potential users on the development of depletion curves for practical application of this model.
Transfer and implement the methods developed within NOHRSC operational System.

4. Diagram of Snowmelt Process and Distribution

5. TODAY'S REPORT Current status of the snow modeling project
Geographical data analysis in the watershed
Point snowmelt modeling
Grid snow modeling

6. ACKNOWLEDGEMENT
Dr. David Tarboton

7. INTRODUCE TO STUDY SITE
The Green Lakes Valley (GLV) along the Colorado Front Range Comprises 8.1 km2, located approximately 35-km northwest of Boulder, CO. Elevation ranges from 3204 to 4087m, with most of the basin lying above treeline. The GLV study area flanks the eastern side of the Continental Divide and is part of the Niwot Ridge Long-Term Ecological Research (LTER) Project.

8. TOOLS
GIS Software: Arcview 3.1 with spatial analysis extension, Sinmap, Tardem Programme Language: Visual C++, Visual FORTRAN, Visual Basic Graphical Tools: Splus 2000
Other tools:

9. PROJECT PROCEDURE Data collect
Formation of Watershed and River Network
Implementation of UEB (Point Model)
Sub-grid Distributed Snowmelt Modeling

10. DEM of the study watershed
The elevation in this watershed ranges from 3221
to 4087 meters with snow covered in the winter.

11. Delineate the river network and watershed
TarDEM
Using Dinf method (d8) contributing area

12. Green Lake Valley watershed by the Tardem Method: Sub watershed and river network

13. Study area data and point snow modeling sites
Data for the modeling sub watershed. Four
weather station is shown in the picture.

14. Modeling cumulative snow melt

15. Modeling snow water equivalence

16. Outline for the Grid Snow modeling

17. GridSnow Modeling Procedure
DEM
Weather Data
Aspect
GridSnow
Slope
SWE Map
View Factor

18. Snow water equivalence map (May, 22 1996)

19. Depletion Curves Method Scale Factor in the Snowmelt Modeling
FUTURE WORK
Depletion Curves Method
Scale Factor in the Snowmelt Modeling

20. QUESTIONS

21. REFERENCE