Abstract
We present a parameter estimation study of the Soil-Tree-Atmosphere Continuum (STAC) model, a process-based model that simulates water flow through an individual tree and its surrounding root zone. Parameters are estimated to optimize the model fit to observations of sap flux, stem water potential, and soil water storage made for a white fir (Abies concolor) in the Sierra Nevada, California. Bayesian inference is applied with a likelihood function that considers temporal correlation of the model errors. Key vegetation properties are estimated, such as the tree's root distribution, tolerance to drought, and hydraulic conductivity and retention functions. We find the model parameters are relatively non-identifiable when considering just soil water storage. Overall, by utilizing multiple processes (e.g. sap flow, stem water potential, and soil water storage) during the parameter estimation, we find the simulations of the soil and tree water properties to be more accurate when compared to observed data.
Original language | English |
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Pages (from-to) | 76-85 |
Number of pages | 10 |
Journal | Environmental Modelling and Software |
Volume | 115 |
DOIs | |
State | Published - May 2019 |
Externally published | Yes |
Funding
The authors appreciate support from the SCGSR fellowship of the Department of Energy (E.M.), the UC-Lab Fees Research Program Award 237285 (E.M.), the LFR-18-542511 (C.X.), and the DOE Office of Science Next Generation Ecosystem Experiment at Tropics (NGEE-T) project (C.X.). The authors are also grateful to Dr. Jasper A. Vrugt for providing the tools needed to conduct this study, including the STAC model source code, the calibration data from the KREW site, as well as discussion that inspired ideas.
Funders | Funder number |
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DOE Office of Science | |
U.S. Department of Energy | 237285, LFR-18-542511 |
Keywords
- Climate
- Ecohydrology
- Hydraulics
- MCMC
- Parameter estimation
- Vegetation