It has long been understood that porous media microstructure has a significant impact on macroscopic multiphase behavior, both in the deep subsurface and the vadose zone. Above the REV scale, continuum descriptions are used to tractably model  large spatial domains, but often over-simplify key physics which fundamentally control  macroscopic fluid migration and porous media deformation. Recent advances in imaging, grain/pore-scale laboratory experiments, and hybrid computational/experimental methods are allowing unprecedented access to this microstructure, opening up the possibility of fundamental advances in the way these multiphase systems are modeled at large scales, both through improved constitutive relations and numerical multiscale methods. In this session, we invite contributions from integrated experimental, numerical and analytical techniques for the characterization and prediction of flow (single/multiphase + granular), transport (conservative/reactive), deformation and wettability across scales. We encourage research which addresses upscaling from the microscale to the continuum scale, driven by experimental observations and data.