Preprints
Filtering by Subject: Physical Sciences and Mathematics
The ocean’s gravity-driven carbon flux from serendipitous particle traps
Published: 2026-10-24
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Particles sinking into the ocean’s interior are a food source for deep-sea ecosystems and sequester carbon from the atmosphere. Yet, measurements of the sinking flux are sparse, leaving substantial uncertainties in its magnitude and variability. We demonstrate how a fleet of Argo floats has serendipitously measured the sinking flux for the last decade because particles settled onto the floats [...]
Incision Sets the Growth Rate of Delta Channel Networks
Published: 2026-10-24
Subjects: Engineering, Physical Sciences and Mathematics
River deltas support large human populations and diverse ecosystems, but many are increasingly threatened by relative sea-level rise and sediment deprivation. Delta growth is widely viewed as a depositional process driven by sediment accumulation. However, the distributary channels that deliver sediment across deltas often extend before major episodes of subaerial land growth. Recent field [...]
Integrating rapid 3D structural validation into interpretation: forward modelling of the Katnook Graben, Otway Basin
Published: 2026-10-24
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Structural validation of a prospect is invariably applied after the interpretation is finished, by restoring one or two key lines in 2D or, rarely, by a full 3D restoration that needs finished horizons and a specialist. The authors propose that a simple 3D kinematic forward model, built in minutes using a few explicit structural rules, fully restorable and scaled onto the mapped horizons, is a [...]
Mapping Ghana's Vanishing Tree Cover: Two Decades of Regional Loss and Shifting Deforestation Hotspots (2001-2024)
Published: 2026-10-24
Subjects: Physical Sciences and Mathematics
Ghana has lost a great deal of tree cover since 2000, but it is less clear where the loss is greatest and whether those places have changed over time. This study used satellite records of tree cover loss from 2001 to 2024 and counted the loss in each of Ghana's 16 regions. Only areas that had at least 30% tree canopy in 2000 were included. Out of about 6.97 million hectares of tree cover in 2000, [...]
NepalDTM: A National 8-Metre Bare-Earth Digital Terrain Model of Nepal from Multi-Source Satellite Data Fusion
Published: 2026-10-24
Subjects: Earth Sciences, Geomorphology, Hydrology, Physical Sciences and Mathematics
NepalDTM is an open bare-earth elevation model of Nepal stored on an 8 m grid. Where the NASA High Mountain Asia 8 m stereo mosaic has a usable height, that mosaic is the surface. Elsewhere the surface is Copernicus GLO-30. A histogram gradient-boosting model, trained on 6,230,548 ICESat-2 points and 7,035,904 GEDI points, predicts how far the surface sits above the ground and subtracts that [...]
Settling-driven Rayleigh–Taylor instability in a pre-existing turbulent field
Published: 2026-10-24
Subjects: Fluid Dynamics, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics
Vertical particle transport controls environmental processes ranging from sediment deposition and the export of organic material and microplastics to the fate of minerals released for carbon dioxide removal. When a particle-laden layer overlies denser water, particles destabilize the interface and descend collectively as convective plumes, far faster than individual settling. Yet this mechanism [...]
Unified Explanation of Long-Period Ground Motion Using the Basin Sloshing Index (BSI): A Dimensionless Analysis of Large-Scale Sloshing Phenomena in Sedimentary Basins
Published: 2026-10-24
Subjects: Physical Sciences and Mathematics
This study introduces a new dimensionless index, the Basin Sloshing Index (BSI), to provide a unified explanation for long-period ground motion and persistent shaking observed in large sedimentary basins. Inspired by fluid sloshing dynamics, BSI is defined using three fundamental parameters—the basin scale L, seismic wavelength λ, and attenuation factor Q —and takes the simplified [...]
On-Fault Parameters and Fault Connectivity Control Synthetic Earthquake Catalogs and 30-Year Rupture Probabilities in RSQSim Simulations of the Eastern San Francisco Bay Area
Published: 2026-10-23
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The faults in the Eastern San Francisco Bay Area in California have long been known as a source of seismic hazard. This potential for large earthquakes, paired with high population density and economic activity leads to high seismic risk in the Bay Area. In this study we utilize the physics-based earthquake simulator RSQSim to generate synthetic earthquake catalogs for the San Francisco East Bay. [...]
Satellite-Based CO and NOx Emission Estimates from South-Central Chilean Plantation Fires
Published: 2026-10-23
Subjects: Environmental Chemistry, Environmental Monitoring, Environmental Sciences, Physical Sciences and Mathematics
We present top-down CO and NOx emission estimates for a south-central Chilean fire from Sentinel-5P/TROPOMI observations. Applying the Cross-Sectional Flux method to CO and the Exponentially Modified Gaussian method to NO2, with uncertainty propagated through 500-member Monte Carlo ensembles, we retrieve a median CO flux of 1,273 kg s⁻¹ (95% CI: 676–1,843 kg s⁻¹) and a median NOx flux of 7,505 g [...]
Pedogenic magnetic enhancement in a Latossolo Vermelho (Oxisol) formed on slate in the Brazilian Cerrado: an integrated record of repeated wetting–drying cycles
Published: 2026-10-22
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
Seasonal wetting–drying cycles in tropical soils can drive redox reactions that control the formation and transformation of ferrimagnetic iron oxides. In the profile-scale case study, we investigated a well-drained, clayey Latossolo Vermelho (Oxisol/ Ferralsol) developed on weakly magnetic slate in the Brazilian Cerrado. The profile was sampled to 190 cm depth in the dry season (July 2023) and at [...]
Robust Regional Predictability of North Atlantic Tropical Cyclones on Seasonal Timescale
Published: 2026-10-22
Subjects: Physical Sciences and Mathematics
Tropical cyclones (TCs) are intermittent extreme weather events, yet their seasonal occurrence can be constrained by slowly varying climate variability and regional predictability remains poorly understood. Using 44 years of May-initialized ensemble hindcasts, we show robust seasonal predictability of North Atlantic TC track density across two prediction systems with contrasting resolutions: [...]
The Dynamics of Nonlinear Triads of Rossby-Haurwitz and Gravity Shallow Water Waves on the Sphere
Published: 2026-10-22
Subjects: Physical Sciences and Mathematics
Understanding the interplay between nonlinearity and multiple scales is one of the cornerstones of geophysical fluids and climate modelling. Nonlinear interactions between atmospheric waves of disparate scales, from fast inertia-gravity waves to slow planetary-scale Rossby-Haurwitz waves, are central to energy cascades and to low-frequency phenomena. Yet, they remain poorly understood beyond [...]
Previously undetected disturbances are the dominant driver of carbon loss in protected Amazonian forests
Published: 2026-10-22
Subjects: Earth Sciences, Forest Management, Geography, Physical Sciences and Mathematics, Remote Sensing, Social and Behavioral Sciences
Amazonian forests face increasing pressures from human-induced deforestation and degradation, compounded by natural disturbances such as droughts and windthrow events. In response, forest protection policies strengthened and formalised large protected areas and Indigenous lands, now covering 43% of the region. However, clearings and degradation in these protected areas are complex and hard to [...]
A 400 Myr subduction memory in the mid-ocean ridge source
Published: 2026-10-21
Subjects: Physical Sciences and Mathematics
The upper mantle sampled by mid-ocean ridges carries the volatile imprint of past subduction, but the global distribution of hydration through time and how long that imprint survives mixing and melt extraction are poorly known. We investigate the history of mantle hydration by calculating where and when hydration occurred using a plate reconstruction model of subducted water over the past 410 [...]
A retrodictive theory of the origin of the Moon: a secondary circumterrestrial disk redistributed by the retrograde flyby of a rocky planet
Published: 2026-10-21
Subjects: Astrophysics and Astronomy, Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Planetary Geochemistry, Planetary Geology, Planetary Sciences, The Sun and the Solar System
The Moon is a datum, and the question is retrodictive: which physical pathways lead to it without a giant impact? The pathway examined starts from a young, hot proto-Earth, soft but never liquid, flattened and inflated by a 6 h rotation, surrounded by a disk of material that has not yet formed a satellite. A second rocky planet, planet B, passes close to the Earth against its rotation, without [...]