arXiv subjects

Jan Bumberger

Publications and source records attributed to Jan Bumberger.

4 recordsLinked to original sources

arXiv2026

Hyperlocal urban NO2 hotspot modeling driven by microscopic traffic data

Road-traffic NO2 hotspots are still often modelled with static emissions and generic temporal profiles, although near-road concentrations respond strongly to rapidly changing traffic conditions. Here, we test whether detector-informed dynamic traffic emissions improve hyperlocal NO2 modelling relative to a conventional static baseline. To this end, we couple an online-calibrated mesoscopic traffic model (SUMO) with the LES-based urban dispersion model CAIRDIO in a nested high-resolution framework for Leipzig, Germany. We compare two otherwise identical experiment setups: a static reference simulation and a coupled simulation in which road-traffic emissions within the SUMO domain are replaced by dynamic emissions derived from simulated traffic states. The framework is designed for city-wide high-resolution application, while the present evaluation focuses on two traffic-oriented hotspot settings during two one-week periods. Compared against hourly NO2 observations of official air quality monitoring, the coupled setup performs better overall, with the clearest improvement at the street-canyon hotspot and in the representation of concentration peaks. Dynamic traffic emissions therefore provide clear added value for hyperlocal NO2 prediction where hotspot realism and exposure-relevant peaks matter.

physics.ao-ph↗

arXiv2026

Criteria-first, semantics-later: reproducible structure discovery in image-based sciences

Across the natural and life sciences, images have become a primary measurement modality, yet the dominant analytic paradigm remains semantics-first. Structure is recovered by predicting or enforcing domain-specific labels. This paradigm fails systematically under the conditions that make image-based science most valuable, including open-ended scientific discovery, cross-sensor and cross-site comparability, and long-term monitoring in which domain ontologies and associated label sets drift culturally, institutionally, and ecologically. A deductive inversion is proposed in the form of criteria-first and semantics-later. A unified framework for criteria-first structure discovery is introduced. It separates criterion-defined, semantics-free structure extraction from downstream semantic mapping into domain ontologies or vocabularies and provides a domain-general scaffold for reproducible analysis across image-based sciences. Reproducible science requires that the first analytic layer perform criterion-driven, semantics-free structure discovery, yielding stable partitions, structural fields, or hierarchies defined by explicit optimality criteria rather than local domain ontologies. Semantics is not discarded; it is relocated downstream as an explicit mapping from the discovered structural product to a domain ontology or vocabulary, enabling plural interpretations and explicit crosswalks without rewriting upstream extraction. Grounded in cybernetics, observation-as-distinction, and information theory's separation of information from meaning, the argument is supported by cross-domain evidence showing that criteria-first components recur whenever labels do not scale. Finally, consequences are outlined for validation beyond class accuracy and for treating structural products as FAIR, AI-ready digital objects for long-term monitoring and digital twins.

cs.CV↗

arXiv2025

Sensor Management System (SMS): Open-source software for FAIR sensor metadata management in Earth system sciences

Deriving reliable conclusions and insights from environmental observational data urgently requires the enrichment with consistent and comprehensive metadata, including time-resolved context such as changing deployments, configurations, and maintenance actions. We have therefore developed the Sensor Management System (SMS), which provides a user-friendly and feature-rich platform for modeling even the most complex sensor systems and managing all sensor-related information across their life cycle. Each entity is described via well-defined terms like Devices, Platforms and Configurations, as well as Sites that are further enhanced with attributes for, e.g., instrument manufacturers, contact information or measured quantities and complemented by a continuous history of system-related actions. By further linking the SMS to sub-sequent systems and services like PID-registration or controlled vocabularies and establishing a community of end-users, the SMS provides the central element of a digital ecosystem, that fosters a more consistent, sustainable and FAIR provision of sensor-related metadata.

cs.SE↗

arXiv2025

Broadband Dielectric Analysis of Clays: Impact of Cation, Exchange Capacity, Water Content, and Porosity

Clay-rich soils and sediments are key components of near-surface systems, influencing water retention, ion exchange, and structural stability. Their complex dielectric behavior under moist conditions arises from electrostatic interactions between charged mineral surfaces and exchangeable cations, forming diffuse double layers that govern transport and retention processes. This study investigates the broadband dielectric relaxation of four water-saturated clay minerals (kaolin, illite, and two sodium-activated bentonites) in the 1 MHz to 5 GHz frequency range using coaxial probe measurements. The dielectric spectra were parameterized using two phenomenological models - the Generalized Dielectric Relaxation Model (GDR) and the Combined Permittivity and Conductivity Model (CPCM) - alongside two theoretical mixture models: the Augmented Broadband Complex Dielectric Mixture Model (ABC-M) and the Complex Refractive Index Model (CRIM). These approaches were evaluated for their ability to link dielectric relaxation behavior to petrophysical parameters such as cation exchange capacity (CEC), volumetric water content (VWC), and porosity. The results show distinct spectral signatures correlating with clay mineralogy, particularly in the low-frequency range. Relaxation parameters, including relaxation strength and apparent DC conductivity, exhibit strong relationships with CEC, emphasizing the influence of clay-specific surface properties. Expansive clays like bentonites showed enhanced relaxation due to ion exchange dynamics, while deviations in a soda-activated bentonite highlighted the impact of chemical treatments on dielectric behavior. This study provides a framework for linking clay mineral physics with electromagnetic methods, with implications for soil characterization, hydrological modeling, geotechnical assessment, and environmental monitoring.

physics.geo-ph↗