Webinar: Subsurface storage and drought in a changing climate in the California Sierra
WhenStart: May 3, 2016 @ 10AM PT
End: May 3, 2016 @ 11AM PT
In water-limited semi-arid systems, a critical eco-hydrology question is how does climate warming influence water availability for both human needs and ecosystem health. Empirical studies and hydrologic theory generally suggest an increase in evapotranspiration with warming. Local responses, however, are more often more complex and both increases and decreases in vegetation water use can occur. Particularly in drought-prone ecosystems changes in climate can dramatically alter ecosystem structure and function through changes in productivity and disturbance regimes such as fire and disease. These changes in ecosystem structure can further alter both short and long term vegetation water demand and use. Similarly human management actions such as fuel treatments alter ecosystem structure with potential feedbacks for vegetation water use and ultimately ground and surface water recharge. Experimental designs to investigate these interactions are often limited to observations of single events: a drought, a fire, a particular climate sequence following a fuel treatment. Mechanistic watershed scale models can consider multiple scenarios and contribute to understanding and ultimately predicting how different landscape controls - local climate, geology and vegetation - influence responses to climate warming. We use RHESSys, a coupled eco-hydrologic model, to disentangle the controls that may influence vegetation water use and streamflow given a warming climate. I present several examples of the application of RHESSys in the California Sierra that highlight the importance of accounting for spatially complex and dynamic controls on vegetation water use and how these change following disturbance and land management actions. These examples also serve to illustrate RHESSys as an evolving modeling approach using state-of-the art software engineering techniques and the integration of data sets from both remote sensing and focused observation networks such as the Critical Zone Observatories.
Dominique Bachelet, Ph.D.
Senior Climate Change Scientist, Team Lead- Global Change