A component-based modular treatment of the soil–plant–atmosphere continuum: the GEOSPACE framework (v.1.2.9)

Abstract. The soil–plant–atmosphere continuum (SPAC) system is a complex and interconnected network of physical phenomena, encompassing heat transfer, evapotranspiration, precipitation, water absorption, soil water flow, substance transport, and gas exchange. These processes govern the exchange of energy and water within the SPAC system. Modeling the SPAC system involves multiple disciplines, including hydrology, ecology, and computational science, making a physically based approach inherently interdisciplinary for capturing the complexity of the system. The present study introduces the Soil–Plant–Atmosphere Continuum Estimator in GEOframe (GEOSPACE), a new ecohydrological modeling framework, in particular its one-dimensional development, GEOSPACE-1D. GEOSPACE leverages and extends selected components from the GEOframe modeling system, while also integrating newly developed modules, to comprehensively simulate water transport dynamics in the SPAC system. The framework of GEOSPACE-1D is a tool designed to facilitate robust, reliable, and transparent simulations of SPAC interactions. It embraces the principles of open-source software and modular design, aiming to promote open, reusable, and reproducible research practices. Instead of relying on a single monolithic model, we propose a component-based modeling approach, where each component addresses a specific aspect of the system. Object-oriented programming (OOP) is adopted as the foundational framework for this approach, providing flexibility and adaptability to accommodate the ever-changing nature of the SPAC system. This compartmentalization serves two critical purposes: validating individual processes against analytical solutions and facilitating the integration of novel processes into the system. The paper emphasizes the significance of modeling the coupling between infiltration and evapotranspiration through two “virtual” simulations based on real-world input data from the “Spike II” experiment to explore the interplay between plant transpiration, soil evaporation, and soil moisture dynamics, highlighting the need to account for these interactions in SPAC models. Overall, GEOSPACE-1D represents an approach to SPAC modeling providing a flexible and extensible framework for studying complex interactions within the Earth's critical zone. It is worth recalling that the fundamental premise of GEOSPACE-1D is not to create a single soil–plant–atmosphere model but to establish a system that allows the creation of a series of soil–plant–atmosphere models adapted to the specific needs of the user's case study.