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- The drag exerted by weakly dissipative trapped lee waves on the atmosphere: application to Scorer's two-layer modelPublication . Teixeira, Miguel A C; Argain, J.Although it is known that trapped lee waves propagating at low levels in a stratified atmosphere exert a drag on the mountains that generate them, the distribution of the corresponding reaction force exerted on the atmospheric mean circulation, defined by the wave momentum flux profiles, has not been established, because for inviscid trapped lee waves these profiles oscillate indefinitely downstream. A framework is developed here for the unambiguous calculation of momentum flux profiles produced by trapped lee waves, which circumvents the difficulties plaguing the inviscid trapped lee wave theory. Using linear theory, and taking Scorer's two-layer atmosphere as an example, the waves are assumed to be subject to a small dissipation, expressed as a Rayleigh damping. The resulting wave pattern decays downstream, so the momentum flux profile integrated over the area occupied by the waves converges to a well-defined form. Remarkably, for weak dissipation, this form is independent of the value of Rayleigh damping coefficient, and the inviscid drag, determined in previous studies, is recovered as the momentum flux at the surface. The divergence of this momentum flux profile accounts for the areally integrated drag exerted by the waves on the atmosphere. The application of this framework to this and other types of trapped lee waves potentially enables the development of physically based parametrizations of the effects of trapped lee waves on the atmosphere.
- Beyond cadaster: landowners and land fragmentation—insights from a case studyPublication . Ferreira da Silva da Costa Freitas, Maria de Belém; Teixeira, Miguel; Rolo Antunes, Carla Maria; César Ribeiro, Henrique; Partidário, Maria do RosárioLand management is a relevant problem in rural areas all over the world, conditioning the planning decisions and the applicability of planning instruments. This study evaluates the limitations of cadastral data in representing land fragmentation and management patterns in wild-fire-prone landscapes, using Alferce (Portugal) as a case study with broader international relevance. Similar challenges—fragmented ownership, incomplete land registries, and increasing wildfire risk—affect many regions worldwide, particularly across the Mediterranean basin and other fire-prone rural landscapes. A mixed-methods approach combines cadastral data with field data from 23 landowners producing two datasets: cadaster-only and ownership-enhanced. Fragmentation is assessed using Simmons and Januszewki indices, supported by spatial analysis (Kernel Density and Moran’s I). Results show that cadastral data alone significantly overestimates fragmentation. While parcel-based analysis suggests a highly fragmented landscape, incorporating ownership information reveals more aggregated management structures. The 23 landowners manage 1247 ha (≈13% of the area), forming a “keystone” group with strong potential for coordinated land management and fire prevention. Higher fragmentation is associated with population centers. These findings demonstrate that cadastral units do not reflect functional management units and considerations about property fragmentation are biased by the lack of information about the owners, a key theoretical contribution with implications beyond Portugal. For policymakers, integrating ownership data and targeting key land managers can improve land use planning and wildfire mitigation and, overall, the sustainability of the territory. Despite limitations (small sample), the approach is transferable to other regions facing similar structural constraints.