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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Water Management and Systems Research » Research » Research Project #446118

Research Project: Accounting for Stem Water Capacitance in Earth Systems and Hydrologic Models

Location: Water Management and Systems Research

Project Number: 3012-13660-010-031-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Aug 1, 2024
End Date: Jul 31, 2026

Objective:
To combine field observations and advanced earth systems modeling to improve the representation of stem water capacitance (storage and release) through the development and testing of plant ecophysiological components. Modeling advances will be used to investigate impacts of capacitance on coupling between forested systems and atmospheric and hydrologic processes.

Approach:
Ecophysiological submodel development will replicate widely used photosynthesis-stomatal conductance schemes that have been implemented in land surface and ecosystem models, but not before in hydrologic models. A meta-analysis of literature physiological parameters will be completed for common forest tree, shrub, and forb species. Parameters will also be calibrated to gas exchange and eddy flux data (where available) when assumption about partitioning eddy flux data into gross production and respiration components can be met. Alternately, eddy flux data will be used to assess physiological model performance at the plot level when available (e.g. Manitou Experimental Forest, Niwot Ridge). Post-fire vegetation recovery will use field observations and remote sensing products such as Landsat or MODIS spectral indices and classified datasets such as LANDFIRE vegetation cover and height. To assess improvement to modeling ecosystem responses, ecophysiological components will be added to the hydrologic and land surface models and evaluated against base-case models without these additions. Impacts on model performance will be assessed by changes to measured versus modeled bias and error statistics (e.g., RMSE, MBE) and to total fluxes of carbon, water, and energy between the land surface and the atmosphere.