Preprints
Filtering by Subject: Physical Sciences and Mathematics
State-Dependent Biophysical Processes Prevented a Late Paleozoic Snowball Earth
Published: 2026-08-21
Subjects: Biogeochemistry, Earth Sciences, Other Earth Sciences, Physical Sciences and Mathematics
Terrestrial vegetation modulates Earth’s climate through two distinct pathways—biogeochemically drawing down CO2 through enhanced organic carbon burial [1, 2] and silicate weathering [3, 4], and biophysically altering surface energy and water balances through potentially competing albedo and evapotranspiration changes [5, 6]. Although the biogeochemical pathway is widely invoked to explain the [...]
Tsunami wavefront backprojection to locate sources of dispersive waves imaged by SWOT during the 2025 M8.8 Kamchatka Earthquake
Published: 2026-08-20
Subjects: Earth Sciences, Physical Sciences and Mathematics
The 29 July 2025 M8.8 Kamchatka earthquake generated a Pacific-wide tsunami that the Surface Water and Ocean Topography (SWOT) mission imaged about 70 minutes later, about 600 km from the source, as a leading crest trailed by a train of short-wavelength dispersive waves. Rather than matching an assumed source forward to the observations, as prior studies of this wavefield have done, we [...]
Abiotic Oxygen and the Limits of Earth Analogy in Exoplanet Biosignature Interpretation
Published: 2026-08-20
Subjects: Physical Sciences and Mathematics
The detection of atmospheric oxygen on a rocky exoplanet is widely regarded as a strong indicator of biological activity. This expectation derives from a single observational precedent: Earth. We argue that this extrapolation conflates two epistemologically distinct categories of knowledge — universal physical laws, which apply to any rocky planet under any conditions, and contingent terrestrial [...]
Explicit Structural Modeling of Geological Horizons Near Fault Networks
Published: 2026-08-20
Subjects: Engineering, Physical Sciences and Mathematics
This article extends the approach of constructing a geological horizon surface near a single tectonic fault to the case of a system of arbitrary, including intersecting, faults. The generalization requires solving four subtasks: formalization of the fault system as a simplicial complex, construction of the modeling domain as a gamma-neighborhood of the cut graph on the triangulation, replacement [...]
What Can We Learn from a Reduced-Dimensional Groundwater Representation for Diagnosing Groundwater–Land Interactions? Insights from the Water Table Ratio
Published: 2026-08-20
Subjects: Engineering, Physical Sciences and Mathematics
Groundwater exerts an important control on land–atmosphere interactions, yet its explicit representation in Earth system models remains computationally prohibitive. Reduced-dimensional metrics, such as the Water Table Ratio (WTR), have been proposed to represent groundwater influences on land–atmosphere interactions. However, their uncertainty, classification stability, and correspondence with [...]
Mapping Ice Slabs over Antarctic Ice Shelves using Quad-Polarization L-band Radar Backscatter
Published: 2026-08-16
Subjects: Physical Sciences and Mathematics
Nearly 3 months of enhanced-resolution, quad-polarization, L-band (1.26 GHz) radar backscatter (σo) image time series are used to map the ice slab extent over the percolation facies of Antarctic ice shelves for the first time from space. Distinctive spatial trends in σo, incidence angle, and polarization signatures mapped via principal component analysis (PCA) are used to develop a [...]
Flooded Rivers, Drying Wetlands, Vanishing Tributaries: Hydrological Paradox of the East Ganga Plains
Published: 2026-08-16
Subjects: Environmental Monitoring, Geomorphology, Hydrology, Natural Resources Management and Policy, Physical Sciences and Mathematics, Sustainability, Water Resource Management
The East Ganga Plains (EGP) present a striking hydrological paradox: while embanked rivers flood with increasing magnitude, adjacent wetlands and groundwater-fed streams are desiccating, and aquifer storage is declining. Using satellite remote sensing and gravimetry, we document that: (i) wetlands exhibit significant water-cover loss despite stable monsoon rainfall; (ii) small rivers and [...]
PyRiverShift: A Gaussian Transect Decomposition Framework for Quantifying Sub-Pixel Lateral Channel Mobility
Published: 2026-08-16
Subjects: Applied Statistics, Earth Sciences, Environmental Indicators and Impact Assessment, Environmental Monitoring, Geomorphology, Hydrology, Physical Sciences and Mathematics, Sedimentology, Water Resource Management
Along many rivers, lateral channel mobility is a key process, yet quantification from freely available multi-decadal 30 m Landsat imagery is constrained by low pixel resolution relative to channel width. We introduce PyRiverShift, a sensor-agnostic spectral decomposition framework. PyRiverShift fits a 1-D Gaussian to NDWI profiles along valley-perpendicular transects, recovering sub-pixel channel [...]
Predicting the reactivity of trawl-disturbed sediment carbon from measurable seabed properties
Published: 2026-08-16
Subjects: Biogeochemistry, Earth Sciences, Physical Sciences and Mathematics, Sedimentology
Mobile bottom-contact fishing gear disturbs a large area of the continental shelf each year. How much carbon that releases depends on how fast the disturbed material is mineralised. Assessments represent that with a first-order rate constant, and because its value is unmeasured they sample it across five orders of magnitude, which makes it their dominant uncertainty. Here the constant is derived [...]
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 [...]