Lateral Flow, Evapotranspiration, and Vegetation Response in the Mountain Critical Zone
Abstract
Climate change will substantially alter hydrologic cycles because of shifts in vegetation as well as direct changes in temperature and precipitation. These vegetation shifts will be particularly important in mountain critical zones where water, energy, and carbon are tightly coupled. The hydrologic changes from vegetation shifts will have important implications for billions of people who rely on mountain systems for critical water resources. However, these changes are difficult to study because of the complex interactions in these mountain critical zones.
We present the results of numerical experiments using a recent coupling of the integrated hydrologic model ParFlow and the Functionally Assembled Terrestrial Ecosystem Simulator (FATES), a cutting-edge vegetation demography model, in the East River, CO. The site of DOE's Watershed Function SFA, the East River is typical of mountain watersheds that supply water to more than 40 million people through the Colorado River. This novel coupled model infrastructure connects realistic integrated surface and subsurface flow in three-dimensions (ParFlow) and state-of-the-science representations of plant processes including evapotranspiration, growth, and mortality (FATES). This coupling allows us to investigate the links between subsurface flow paths and vegetation evapotranspiration with feedbacks for plant growth and mortality. First, we investigate the differences in evapotranspiration between a stand-alone FATES simulation, a ParFlow-FATES simulation that includes lateral subsurface flow, and a ParFlow-CLM simulation with a less sophisticated plant representation. We isolate the magnitude of evapotranspiration shifts from lateral subsurface flow by using a static vegetation stand structure for comparisons across these simulations. We then enable dynamic vegetation processes that alter the distribution of vegetation across the watershed based on variable water availability from lateral flow to explore the shifts in evapotranspiration in such a dynamic system. This work represents a cutting-edge investigation into interactions between hydrologic processes and vegetation that will shift at landscape scale as the climate continues to change, and will have substantial effects for both mountain ecosystems and downstream water resources.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.H22E..02D