1. Effects of Temperature and Precipitation Changes on a Small Watershed in the Northeastern U.S. Jon Goodall Nathan Johnson Cynthia Lancaster Amy Neuenschwander Gil Strassberg

2. Sleepers River Watershed Vermont – USGS cold area historical data base Covers 111.25 km 2 Land cover is 67% Forest and 33% Agriculture

3. Climate of Sleepers River Precipitation: 1,100 mm/yr (25% snow) Snow cover is continuous November through April Sleepers River Average monthly precipitation

4. Climate of Sleepers River Average Monthly Downward Shortwave Radiation Average Monthly Downward long wave Radiation

5. Climate of Sleepers River Average monthly air temperatures Average monthly specific humidity Specific humidity correlates well with temperature - expected

6. Experiment design Two experiments with changing the forcing data: 1.Increasing and decreasing T by 2 o 2.Increasing and decreasing precipitation by a factor of 2 Global warming Change in precipitation patterns

7. Experiment Increased evapotranspiration (both transpiration and soil evaporation) Decreased soil moisture Increased sensible heat Changes in patterns of snow depth and snowmelt (i.e. lesser snow depths and earlier snowmelt) Scenario 1: Temperature change scenario Hypothesis: Observed data: Soil evaporation Transpiration Total evapotranspiration Sensible heat flux Snow depth Snowmelt

8. Experiment Scenario 1: Temperature change scenario Canopy evaporation was small

9. Experiment Scenario 1: Temperature change scenario

10. Experiment Scenario 1: Temperature change scenario

11. Experiment Scenario 1: Temperature change scenario

12. Conclusions - Temperature change scenario Evapotranspiration (soil evaporation and transpiration) is positively correlated with temperature Soil moisture results were not consistent Sensible heat fluxes were negatively correlated with temperature Snow depths were negatively correlated with temperature Snowmelt generally occurs earlier in the spring with increased temperatures

13. Experiment increasing precipitation will increase runoff will increase infiltration will increase soil moisture will increase and delay snow melt Scenario 2: Precipitation change scenario Hypothesis: Observed data: Runoff Infiltration Soil moisture Snow melt

14. Experiment Scenario 2: Precipitation change scenario

15. Experiment Scenario 2: Precipitation change scenario

16. Conclusions - Precipitation change scenario Precipitation is positively correlated with: –Runoff –Snowmelt –Infiltration –Snow depth Soil moisture drives the cycle High soil moisture during “dry” scenario during winter months –Due to snow or model “ramping”?