Stable boundary layers commonly form during Arctic polar night, but their correct representation poses a major challenge for numerical weather prediction (NWP) systems. To perform detailed model verification by probing the lower boundary layer, airborne fiber-optic distributed sensing (FODS), tethered sonde and ground-based eddy-covariance measurements are carried out during contrasting synoptic forcings in a fjord-valley system in Svalbard. The FODS-derived turbulent potential energy and static stability profiles are used to investigate the spatial and temporal evolution of different inversion types. The observed vertical temperature and wind speed profiles are compared to two configurations of the HARMONIE-AROME system with different horizontal resolutions of 2.5 km and 0.5 km. The higher-resolved model captures cold pool and low level jet formation during weak synoptic forcing, resulting in a well-represented vertical temperature profile, while the coarser model exhibits a warm bias in near-surface temperatures up to 8 K. During changing background flow, the higher-resolved model is more sensitive to misrepresented wind directions. The results indicate the importance of the ratio between nominal model resolution and valley width to represent stable boundary layer features. Kinetic and potential energy spectra are examined for the two model configurations to derive the effective resolutions. The higher-resolved model has also a higher effective resolution, but is more diffusive than the coarser model. Our results underline the substantial benefit of spatially resolving FODS measurements for model verification studies and underline the importance of model and topography resolution for accurate representation of stable boundary layers in complex terrain.