The Accelerated Climate Modeling for Energy (ACME) program is an ongoing multi-laboratory and multi-institutional collaboration project aiming to build a next-generation Earth system model. “How do biogeochemical cycles interact with global climate change” is one of the three high-level science drivers for ACME. Explicit representation of microbial communities and functions in soil biogeochemistry (BGC) processes is a major task in the ACME Land Model (ALM) development. Multiple microbial functional groups are incorporated into the Convergent Trophic Cascade (CTC) reaction network to mediate the decomposition of litter and soil organic matter. Microbial dormancy is included to represent microbial physiological states coping with environmental stress, such as substrate and soil moisture availability. The microbe-enabled soil BGC module needs to be coupled to the soil physics module and the aboveground vegetation module in ALM. As a first attempt towards a flexible and extensible coupling between various modules, a generic BGC interface has been developed to support the coupling between these modules. The general functions of the coupling interface include passing data between modules and allowing a selection of multiple instances of the aforementioned ALM modules. This interface is also designed to accommodate the new phosphorus-cycle state and flux variables. Relevant ALM subroutines were modularized to make the soil BGC sub-model standalone so that any alternative model (e.g., PFLOTRAN) could be called to replace the original ALM soil BGC sub-model.
Results/Conclusions
The development of the generic BGC interface in ALM allows use of multiple instances of the litter and soil BGC module, e.g. the standard ALM BGC model (CTC or CENTURY) and the PFLOTRAN soil BGC reaction network. Built upon the BGC interface, we are developing the microbe-enabled decomposition and methane module and parameterizing and evaluating the new ALM BGC module at site and global scales.