Modeling perennial bioenergy crops in the E3SM land model (ELMv2)

Authors: SINHA, EVA - Pacific Northwest National Laboratory; CALVIN, KATE - Pacific Northwest National Laboratory; BOND-LAMBERTY, BEN - Pacific Northwest National Laboratory; DREWNIAK, BETH - Argonne National Laboratory; RICCIUTO, DAN - Oak Ridge National Laboratory; SARGSYAN, KHACHIK - Sandia National Laboratory; CHENG, YANYAN - Pacific Northwest National Laboratory; Bernacchi, Carl; MOORE, CAITLIN - University Of Western Australia

Submitted to: Journal of Advances in Modeling Earth Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2022
Publication Date: 1/1/2023
Citation: Sinha, E., Calvin, K., Bond-Lamberty, B., Drewniak, B., Ricciuto, D., Sargsyan, K., Cheng, Y., Bernacchi, C.J., Moore, C. 2023. Modeling perennial bioenergy crops in the E3SM land model (ELMv2). Journal of Advances in Modeling Earth Systems. 15(1). Article e2022MS003171. https://doi.org/10.1029/2022MS003171.
DOI: https://doi.org/10.1029/2022MS003171

Interpretive Summary: Perennial bioenergy crops, which are crops that live for multiple years and are potentially used for energy production of, for example, ethanol are increasing considered as a means to offset pollutants that cause global warming. One of the most widely used ecosystem models, which is a tool to predict growth of various different plants globally, does not include these perennial bioenergy crops. This study incorporated these crops into the model and studied the potential for them to offset global warming. The model was calibrated using measurements of two perennial bioenergy crops, miscanthus and switchgrass, and showed that the model is able to accurately predict what was measured. This research provides a useful tool for scaling perennial bioenergy crops globally with the goal of understanding where they can be grown and the impact that they might have on earths climate system.

Technical Abstract: Perennial bioenergy crops are increasingly important for the production of ethanol and other renewable fuels, and as part of an agricultural system that alters the climate through its impact on biogeophysical and biogeochemical properties of the terrestrial ecosystem. Few Earth System Models (ESMs) represent such crops, however. In this study, we expand the Energy Exascale Earth System Land Model to include perennial bioenergy crops with a high potential for mitigating climate change. We focus on high-productivity miscanthus and switchgrass, estimating various parameters associated with their different growth stages and performing a global sensitivity analysis to identify and optimize these parameters. The sensitivity analysis identifies five parameters associated with phenology, carbon/nitrogen allocation, stomatal conductance, and maintenance respiration as the most sensitive parameters for carbon and energy fluxes. We calibrated and validated the model against observations and found that the model closely captures the observed seasonality and the magnitude of carbon fluxes. The validated model represents the latent heat flux fairly well, but sensible heat flux for miscanthus is not well captured. Finally, we validated the model against observed leaf area index (LAI) and harvest amount and found modeled LAI captured observed seasonality, although the model underestimates LAI and harvest amount. This work provides a foundation for future ESM analyses of the interactions between perennial bioenergy crops and carbon, water, and energy dynamics in the larger Earth system, and sets the stage for studying the impact of future biofuel expansion on climate and terrestrial systems.