Preprints
Filtering by Subject: Physical Sciences and Mathematics
A satellite blind spot masks crop residue burning across northern India
Published: 2026-08-15
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
Postmonsoon crop residue burning in the Indian states of Punjab and Haryana is a major source of air pollution and air quality degradation across the Indo-Gangetic Plain (IGP). Recent satellite observations have revealed an apparent inconsistency between declining fire detections and persistent or increasing atmospheric pollution. Here we combine eight years (2018-2025) of fire observations from [...]
Enhancing High-Impact Rainfall Forecasts via Multi-Sensor, Multi-Stage Variational Data Assimilation in WRF: Insights from the CYGMEN Project
Published: 2026-08-15
Subjects: Physical Sciences and Mathematics
Assimilating high-resolution radar reflectivity and complementary observation types remains a central challenge for improving short-term quantitative precipitation forecasts of severe Mediterranean weather systems. This study investigates the effect of multi-source data assimilation configurations using the Weather Research and Forecasting (WRF) model and its three-dimensional variational data [...]
Masked Autoencoding (MAE) Outperforms Joint-Embedding Prediction (JEPA) for Frozen-Probe Very-High-Resolution Landslide Segmentation
Published: 2026-08-15
Subjects: Physical Sciences and Mathematics
Mapping landslides from very-high-resolution (VHR) imagery is central to regional hazard assessment, yet supervised segmentation is constrained by the cost of expert pixel-level annotation. Self-supervised learning can exploit large unlabeled aerial archives, but which pretext objective best captures landslide morphology is unknown. Using a regional inventory from the 2023 Emilia-Romagna rainfall [...]
The Coastal Resilience Safety Factor: A General Method for Coastal Design Under Deep Uncertainty, with a Vancouver Application
Published: 2026-08-15
Subjects: Engineering, Physical Sciences and Mathematics
Global sea level rise is accelerating, and a substantial portion of the coming rise is now committed regardless of future emissions; coastal cities must therefore shift from preventing the hazard to designing for it. That shift poses a question every other safety-critical discipline already answers in its own domain: how large a design margin a structure should carry when the load is deeply [...]
Stokes flow in logarithmic-viscosity space: velocity renormalization and a reference-operator formulation
Published: 2026-08-13
Subjects: Fluid Dynamics, Physical Sciences and Mathematics, Planetary Geophysics and Seismology
Effective viscosity in crystalline solids commonly depends exponentially on temperature, pressure, composition and other state variables, producing spatial variations over many orders of magnitude and making variable-viscosity Stokes flow numerically demanding. We develop an exact, coordinate-independent reformulation using logarithmic viscosity \(\Lambda=\ln(\eta/\eta_0)\) and renormalized [...]
A process-based framework for regional landslide debris inundation hazard assessment: application to the West Coast region of New Zealand
Published: 2026-08-12
Subjects: Physical Sciences and Mathematics
Regional landslide debris inundation hazard assessments commonly rely on scenario-based formulations that require explicit enumeration of discrete landslide events. While effective for local studies, these approaches are computationally intensive, sensitive to scenario design choices, and difficult to apply consistently at regional scales where landslide catalogues are incomplete and long-term [...]
Obliquity limit of megathrust earthquakes
Published: 2026-08-12
Subjects: Physical Sciences and Mathematics
The largest earthquakes occur on subduction-zone megathrusts, where plates commonly converge obliquely to trenches and generate trench-parallel strain. How this strain is partitioned between megathrust slip and upper-plate deformation remains uncertain, hindering earthquake recurrence estimates. Here we combine global slab geometry, plate motions, and earthquake focal mechanisms to quantify [...]
Model-Free Relative Permeability Estimation and Oil Recovery Prediction in Reservoir Rocks from Capillary Pressure Curves
Published: 2026-08-12
Subjects: Engineering, Physical Sciences and Mathematics
This paper presents and validates a model-free method for predicting the relative permeability and oil recovery of reservoir rocks directly from the shape of the capillary pressure curve, tested against real reservoir core, digital rock models, and a large soil-hydraulic dataset. Relative permeability is the key saturation function governing production forecasts, water cut, and oil recovery in [...]
Locating the Anthropogenic Drivers of Urban Flooding from Centimetre-Resolution Aerial Imagery: A Reproducible Open-Data Pipeline for the Odaw Basin, Accra
Published: 2026-08-12
Subjects: Earth Sciences, Environmental Sciences, Hydrology, Physical Sciences and Mathematics
Recurrent inundation in metropolitan Accra is, on the preponderance of the evidence, an anthropogenic rather than a climatological phenomenon: its proximate determinants are the obstruction of drainage by solid waste and the encroachment of structures onto watercourses. These determinants are metre-scale and therefore invisible to the moderate-resolution satellite imagery on which prior work has [...]
IPOC-Deep: a new seismicity catalog for Northern Chile with >2 million events
Published: 2026-08-12
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We present a novel seismicity catalog for Northern Chile, which covers 17 years (2007--2023) of data and contains more than 2.2 million events. Raw waveform data from nearly 200 stations including a range of temporary deployments were processed with state-of-the-art algorithms for phase picking (EQTransformer) and association (PyOcto), after which we performed absolute event relocation in a 2.5D [...]
Barrier vulnerability following outwash: A balance of overwash and dune gap recovery
Published: 2026-08-11
Subjects: Engineering, Physical Sciences and Mathematics
Existing barrier evolution models only simulate storm impacts from landward-driven flows (overwash), neglecting the impacts of seaward-directed flows (outwash). Here, we modify an existing model to incorporate outwash processes. We find that outwash enhances barrier vulnerability (the tendency to drown) over decadal timescales by scarring the island interior, creating lower, narrower landforms. [...]
Spatiotemporal Patterns and Human Accessibility of the July 2026 Northern Algeria Wildfires: An Event-Based Statistical Analysis
Published: 2026-08-09
Subjects: Earth Sciences, Physical Sciences and Mathematics
Northern Algeria experienced a widespread wildfire outbreak between 20 and 24 July 2026, coinciding with an exceptional regional heatwave. This report presents an independent, multi-method statistical analysis of satellite-detected fire activity (NASA VIIRS/FIRMS, n = 4,105 raw detections) to evaluate whether the spatial and temporal structure of these fires — together with their proximity to [...]
Submesoscale frontal dynamics modulate ocean heat transport beneath Antarctic sea ice
Published: 2026-08-06
Subjects: Physical Sciences and Mathematics
Antarctic sea ice has experienced unprecedented declines in recent years, yet the processes governing the transfer of subsurface ocean heat toward the ice remain poorly understood. Here, sub-kilometer hydrographic observations collected by an instrumented seal reveal intense, intermittent, and bidirectional vertical heat transport beneath sea ice in the East Antarctic marginal ice zone. During a [...]
Mapping Urban Heat Vulnerability in London: Multi-Scale Geospatial Analysis Using Machine Learning, SHAP Explainability, and Temporal Mortality Data
Published: 2026-08-06
Subjects: Environmental Sciences, Physical Sciences and Mathematics
Urban heat is a significant cause of mortality. In London, during the summer of 2022, the United Kingdom experienced its first recorded 40°C day, resulting in excess mortality levels not observed since pre-antibiotic influenza seasons. On 19 July 2022, London reached a temperature of 40.3°C, the highest recorded in the United Kingdom, which corresponded to 18,435 excess deaths in England and [...]
Split-Spectrum InSAR for Reliable Ionospheric Correction: A Critical Review of Uncertainty, Validation, and Reproducibility
Published: 2026-08-05
Subjects: Earth Sciences, Physical Sciences and Mathematics
Split-spectrum interferometry provides a physically grounded means of separating dispersive ionospheric phase from non-dispersive deformation-related phase in Interferometric Synthetic Aperture Radar observations. Its practical reliability, however, depends on processing choices that are often reported incompletely and validated inconsistently. This critical narrative review examines the physical [...]