1. Modeling and Analysis of Snowpack over the Western United States Jiming Jin Departments of Watershed Sciences and Plants, Soils, and Climate

3. Trends of Snow Depth over the Western U.S. (1951- 1997)

4. Mount Hood, Oregon

6. Barnett et al., 2008 Computerized projections of western United States snowfall levels in 2050 compared to present day

7. Cannon et al., 2006 Computerized snow-water amounts between now (top) and the century's end (bottom)

8. The Pacific/North America Pattern (Positive) PNA = 0.25[Z (20 o N, 160 o W) -Z(45 o N, 165 o W) + Z(55 o N, 115 o W) –Z(30 o N, 85 o W)]

9. The Pacific/North America Pattern (negative) PNA = 0.25[Z (20 o N, 160 o W) -Z(45 o N, 165 o W) + Z(55 o N, 115 o W) –Z(30 o N, 85 o W)]

10. Snow Anomalies Over the western U.S.

11. EOF = Empirical Orthogonal Functions

12. Precipitation and Temperature Anomalies Over the western U.S.

13. 500 mb Geopotential Height Anomalies

14. Precipitation and Temperature Anomalies Over the western U.S.

15. 500 mb Geopotential Height Anomalies

16. Snotel Stations Over the Sierra Nevada

17. Snow Simulations from a Regional Climate Model The Fifth Generation Mesoscale Model (MM5)/ Noah Land Surface Model

18. Temperature Simulations from a Regional Climate Model

19. Precipitation Simulations from a Regional Climate Model

20. Snow Depth simulations from the Weather Research Forecasting (WRF) Model for the Columbia River Basin

21. Summary 1) The snowpack in the western U.S. is significantly affected by global warming. 1) The interanuual variability of the atmosphere is closely correlated with the snow depth in the western U.S. 2) Our improved version of a regional climate model can realistically simulate the snow depth, and this model can be further used to predict the amount of snow mass.