@Article{Yang_Biogeosci_20230717,
 author		= {Xiaojuan Yang and Peter E. Thornton and Daniel Ricciuto and Yilong Wang and Forrest M. Hoffman},
 title		= {Global Evaluation of Terrestrial Biogeochemistry in the {E}nergy {E}xascale {E}arth {S}ystem {M}odel ({E3SM}) and the Role of the Phosphorus Cycle in the Historical Terrestrial Carbon Balance},
 journal	= Biogeosci,
 volume		= 20,
 number		= 14,
 pages		= {2813--2836},
 doi		= {10.5194/bg-20-2813-2023},
 day		= 17,
 month		= jul,
 year		= 2023,
 abstract	= {The importance of carbon (C)--nutrient interactions to the prediction of future C uptake has long been recognized. The Energy Exascale Earth System Model (E3SM) land model (ELM) version 1 is one of the few land surface models that include both N and P cycling and limitation (ELMv1-CNP). Here we provide a global-scale evaluation of ELMv1-CNP using the International Land Model Benchmarking (ILAMB) system. We show that ELMv1-CNP produces realistic estimates of present-day carbon pools and fluxes. Compared to simulations with optimal P availability, simulations with ELMv1-CNP produce better performance, particularly for simulated biomass, leaf area index (LAI), and global net C balance. We also show ELMv1-CNP-simulated N and P cycling is in good agreement with data-driven estimates. We compared the ELMv1-CNP-simulated response to CO$_2$ enrichment with meta-analysis of observations from similar manipulation experiments. We show that ELMv1-CNP is able to capture the field-observed responses for photosynthesis, growth, and LAI. We investigated the role of P limitation in the historical balance and show that global C sources and sinks are significantly affected by P limitation, as the historical CO$_2$ fertilization effect was reduced by 20\% and C emission due to land use and land cover change was 11\% lower when P limitation was considered. Our simulations suggest that the introduction of P cycle dynamics and C--N--P coupling will likely have substantial consequences for projections of future C uptake.}
}