ORCID Profile
0000-0002-6448-0694
Current Organisation
The Ohio State University
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Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-10820
Abstract: Species-specific hydraulic traits play a critical role in determining the response of ecosystem carbon and water fluxes to water stress. Improving the representation of plant hydraulic behavior in vegetation and land-surface models is critical for improving our predictions of the impacts of water stress on ecosystem carbon and surface fluxes given that bio erse representation of forest canopies remain challenging for land-surface models. Here, we use FETCH3.14, a multispecies, canopy-level, hydrodynamic transpiration model which builds upon the previous versions of the Finite-difference Ecosystem-scale Tree Crown Hydrodynamics model (FETCH). FETCH3.14 is parameterized by our newly developed package, Bayesian Optimization for Anything (BOA), which facilitates and eases hyperparameter optimization using multi-scale and multi-variate observations. BOA incorporates multiple sources of data easily, reduces optimization setup time, and eases advanced use cases such as High-Performance Computing (HPC) parallelization and optimization restarting. BOA facilitates multi-source data assimilation for FETCH3.14 from a disparate range of sources including ET observations, soil and stem water potential observations, and carbon flux observations to provide insights about species-specific hydraulic traits. We use flux data from representative model trees that get scaled to the plot level based on the composition of species and structure of the canopy in the plot, which allows parameterization using tree level observations (sap flux, stem water storage) and plot level observations (eddy covariance evapotranspiration). We use BOA to set up a multi-objective optimization inverse problem with little overhead or extra boilerplate code. This approach allows us to utilize multi-scale observations to resolve information about species-specific hydraulic parameters, including parameters that are difficult or impossible to measure in the field.
Publisher: Copernicus GmbH
Date: 02-09-2021
DOI: 10.5194/GMD-2021-270
Abstract: Abstract. Modelling the water transport along the soil-plant-atmosphere continuum is fundamental to estimating and predicting transpiration fluxes. A tree-hydrodynamic model (SPAC-3Hpy) for the water fluxes across the soil-plant-atmosphere continuum is presented here. The model combines the water transport pathways to one vertical dimension, and assumes that the water flow through the soil, roots, and above-ground xylem can be approximated as a flow in porous media. This results in a system of three partial differential equations resembling the Richardson-Richards equation describing the transport of water through the plant system and with additional terms representing sinks and sources for the transfer of water from to the soil to the roots and from the leaves to the atmosphere. The numerical scheme, developed in Python 3, was tested against exact analytical solutions for steady state and transient conditions using simplified but realistic model parametrizations. The model was also used to simulate a previously published case study where observed transpiration rates were available in order to evaluate model performance. With the same model setup as the published case study, SPAC-3Hpy results were in agreement with observations. Through a rigorous coupling of soil, roots, and hydroactive xylem, SPAC-3Hpy can account for variable capacitance while conserving mass and the continuity of the water potential between these three layers. SPAC-3Hpy provides a ready-to-use open access numerical model for the simulation of water fluxes across the soil-plant-atmosphere continuum.
Publisher: Wiley
Date: 31-12-2021
Publisher: American Geophysical Union (AGU)
Date: 04-2020
DOI: 10.1029/2019WR026058
Abstract: The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) was launched to the International Space Station on 29 June 2018 by the National Aeronautics and Space Administration (NASA). The primary science focus of ECOSTRESS is centered on evapotranspiration (ET), which is produced as Level‐3 (L3) latent heat flux ( LE ) data products. These data are generated from the Level‐2 land surface temperature and emissivity product (L2_LSTE), in conjunction with ancillary surface and atmospheric data. Here, we provide the first validation (Stage 1, preliminary) of the global ECOSTRESS clear‐sky ET product (L3_ET_PT‐JPL, Version 6.0) against LE measurements at 82 eddy covariance sites around the world. Overall, the ECOSTRESS ET product performs well against the site measurements (clear‐sky instantaneous/time of overpass: r 2 = 0.88 overall bias = 8% normalized root‐mean‐square error, RMSE = 6%). ET uncertainty was generally consistent across climate zones, biome types, and times of day (ECOSTRESS s les the diurnal cycle), though temperate sites are overrepresented. The 70‐m‐high spatial resolution of ECOSTRESS improved correlations by 85%, and RMSE by 62%, relative to 1‐km pixels. This paper serves as a reference for the ECOSTRESS L3 ET accuracy and Stage 1 validation status for subsequent science that follows using these data.
Publisher: Copernicus GmbH
Date: 31-03-2022
Abstract: Abstract. Modelling the water transport along the soil–plant–atmosphere continuum is fundamental to estimating and predicting transpiration fluxes. A Finite-difference Ecosystem-scale Tree Crown Hydrodynamics model (FETCH3) for the water fluxes across the soil–plant–atmosphere continuum is presented here. The model combines the water transport pathways into one vertical dimension, and assumes that the water flow through the soil, roots, and above-ground xylem can be approximated as flow in porous media. This results in a system of three partial differential equations, resembling the Richardson–Richards equation, describing the transport of water through the plant system and with additional terms representing sinks and sources for the transfer of water from the soil to the roots and from the leaves to the atmosphere. The numerical scheme, developed in Python 3, was tested against exact analytical solutions for steady state and transient conditions using simplified but realistic model parameterizations. The model was also used to simulate a previously published case study, where observed transpiration rates were available, to evaluate model performance. With the same model setup as the published case study, FETCH3 results were in agreement with observations. Through a rigorous coupling of soil, root xylem, and stem xylem, FETCH3 can account for variable water capacitance, while conserving mass and the continuity of the water potential between these three layers. FETCH3 provides a ready-to-use open access numerical model for the simulation of water fluxes across the soil–plant–atmosphere continuum.
Publisher: Copernicus GmbH
Date: 02-09-2021
No related grants have been discovered for Justine Missik.