As the range of processes and scales to which subsurface flow and reactive transport models are applied has become very broad (e.g., involving multiphase flow, multicomponent heterogeneous reactions, microbiological processes, coupled geomechanics), many problems are being encountered for which classical continuum model assumptions are not met. However, it is usually impractical to perform application-scale simulations at sub-continuum-scale resolution. This motivates the development of hybrid multiscale methods, in which model formulations posed at multiple length and time scales (e.g., molecular, pore, continuum scales) are simultaneously employed within a single simulation framework.
We solicit contributions that describe theoretical developments and numerical methods for hybrid multiscale modeling, as well as applications of hybrid multiscale models to specific problems. Although many of these are likely to involve coupling of pore- and continuum-scale models, we are also interested in couplings across other scales (for example, molecular to pore scales, or from field- to basin-scales). We also encourage contributions on approaches on new multiscale closures, reduced-order models, multiscale error estimation, uncertainty quantification, adaptive control, multiscale data assimilation and approaches focusing on ultralong time predictions and how these couple to faster dynamics, as imposed, e.g., by boundary conditions or source terms.