Preprints
Filtering by Subject: Physical Sciences and Mathematics
Coupled in-reservoir and downstream water-temperature responses to the deep drawdown of a large reservoir, and tradeoffs for fisheries management
Published: 2026-10-10
Subjects: Life Sciences, Physical Sciences and Mathematics
Across the Pacific Northwest and other regions, the construction and operation of large dams has provided numerous societal benefits but has also fundamentally altered present-day river networks by blocking fish passage and altering streamflows and thermal regimes. Increasingly, evolving management directives require dam operations far outside of historical operational regimes to achieve new [...]
A scaling law for stagnant-lid convection with composite visco-elasto-plastic rheology: application to Europa's ice shell
Published: 2026-10-09
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Planetary Geology, Planetary Sciences, Tectonics and Structure
Scaling laws relating the Nusselt number (Nu) and the Rayleigh number (Ra) are the standard tool for translating numerical models of convection into predictions of surface heat flux and the thicknesses of the stagnant lid and the rheological sublayer. Existing scaling frameworks for icy moons normalise this relationship using a temperature-dependence parameter, γ, calibrated against viscous and [...]
Groundwater Potential Mapping in Northwestern Nigeria: A Comparison of the Analytic Hierarchy Process and Galileo-Enhanced CAT-XGB
Published: 2026-10-09
Subjects: Earth Sciences, Environmental Sciences, Hydrology, Physical Sciences and Mathematics, Water Resource Management
Global water scarcity intensifies the need for high-resolution groundwater assessment tools, yet traditional approaches struggle to reconcile qualitative expert weights with the extensive spatial coverage offered by remote sensing data. This study presents a comparative framework evaluating expert-driven Multi-Criteria Decision Analysis (a ten-layer Analytic Hierarchy Process (AHP)) against [...]
P- and S-Wave Travel-Time Characteristics and Station-Dependent Residuals from Local Earthquakes in Ghana
Published: 2026-10-09
Subjects: Physical Sciences and Mathematics
Understanding P- and S-wave travel-time behaviour is important for characterizing seismic-wave propagation and identifying station-dependent variability within regional seismic networks. This study investigates P- and S-wave travel-time characteristics and station-dependent residuals using local earthquakes recorded by the Ghana Digital Seismic Network (GHDSN). The analysis reexamines the [...]
The critical role of stored energy in metamorphism
Published: 2026-10-09
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics
The mechanical behaviour of the Earth is widely assumed to change with increasing timescale as rocks progressively relax imposed stresses [1]. On short timescales, elasticity dominates and its release drives earthquakes [2]; at intermediate timescales, viscoelastic relaxation facilitates processes such as glacial rebound [3]; whereas over geological timescales viscous deformation dominates, [...]
Tectonic history of East Asia and the Asiana hypothesis
Published: 2026-10-09
Subjects: Physical Sciences and Mathematics
When almost all continents were assembled in the late Paleozoic supercontinent Pangea, East Asian continental blocks existed as distinct, separate entities. Ocean closures and stepwise assembly of these blocks into larger continents were the main paleogeographic changes to influence paleoclimate and biogeography during Pangea time. In this Perspective, we review how Triassic assembly of the East [...]
Temporal Synchronization Determines the Accuracy of Sentinel-2 Turbidity Retrieval: Evidence from Community-Based Monitoring of the Buriganga River, Dhaka
Published: 2026-10-07
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
Community-based environmental organizations require continuous water quality data but are constrained by the cost and labor of physical sampling. Satellite remote sensing offers a free alternative, yet validation studies of inland waters frequently report weak agreement between satellite indices and ground measurements, and the cause of that disagreement is rarely isolated. This study analyzed 28 [...]
Lunar South Pole Resource Prospectivity: A Multi- Instrument Framework and a Testable Model for Heterogeneous Volatile Emplacement
Published: 2026-10-06
Subjects: Physical Sciences and Mathematics
Water ice and other volatiles in lunar south-polar permanently shadowed regions (PSRs) are established exploration targets, but their abundance, geometry, continuity, and depth distribution remain incompletely constrained. We present a physically informed, AI-assisted framework integrating neutron-derived hydrogen abundance, Diviner thermal stability, radar circular polarization ratio (CPR), [...]
Ultramafic weathering in tropical volcanic arcs: Geochemistry and inverse modeling of rivers draining the Zambales Ophiolite Complex (ZOC), Philippines
Published: 2026-10-06
Subjects: Physical Sciences and Mathematics
Mafic and ultramafic rocks are highly susceptible to silicate weathering, a key negative feedback which modulates atmospheric CO2 over geological timescales. The tectonic exposure of these reactive lithologies, such as the Neogene uplift of the volcanic islands in maritime Southeast Asia, has been hypothesized to enhance this global feedback and contribute to long-term global cooling. However, [...]
Hydrogen gas (H₂) artificially generated during soil-gas sampling - Technical report
Published: 2026-10-05
Subjects: Physical Sciences and Mathematics
Surface gas geochemistry methods, including soil gas measurements, are widely used for natural hydrogen (H₂) exploration. It is known that H₂ can be artificially generated by mechanical friction during installation of soil-gas probes. However, it is frequently considered that artificial H₂ is produced only by drill bit rotation, although there are no systematic studies about its generation during [...]
COVID-19 Emission Reductions Reveal the Efficiency and Warming Impact of Short-Lived Greenhouse Gases
Published: 2026-10-05
Subjects: Physical Sciences and Mathematics
The COVID-19 response provided a natural experiment to quantify the climate forcing efficiency of short-lived pollutants. Using satellite-constrained reanalysis and chemistry-climate simulations, we isolate the radiative impacts of anthropogenic NOₓ reductions through two modes: a rapid ozone decrease and a slower methane-driven adjustment that dominates the net effect. Globally, these responses [...]
A Stable Column ΔXCH₄/ΔXCO₂ Ratio over Los Angeles (2011–2025): An Inventory-Independent Test of Urban Methane Policy
Published: 2026-10-05
Subjects: Physical Sciences and Mathematics
We extend the column-averaged CH₄ and CO₂ (XCH₄, XCO₂) record from the California Laboratory for Atmospheric Remote Sensing (CLARS) through July 2025, spanning 15 years over the Los Angeles megacity. CLARS retrievals show persistent enhancements of both gases above the free-tropospheric background, with a strong excess correlation (R = 0.93) and an emission ratio ΔXCH₄/ΔXCO₂ ≈ 5.1 ppb ppm⁻¹ that [...]
Natural aerosol variability can reverse the apparent air-quality response to abrupt emission reductions
Published: 2026-10-05
Subjects: Physical Sciences and Mathematics
Abrupt societal disruptions, including economic shocks, pandemic lockdowns, and armed conflicts, are widely used as natural experiments for attributing changes in air quality to changes in emissions. Such attribution commonly rests on observed concentrations: combustion tracers fall, and the resulting improvement is credited to reduced emissions. Here we show that coincident natural aerosol [...]
Bulk iron-sulfur ratio (Fe/S) conditional proxy for sulfurized, TOC-rich sediments: insights and comparison of compositional model with real data utilizing the Pyrite-TOC-Fe-S compositional space
Published: 2026-10-05
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
Bulk iron-sulfur (Fe/S) ratio can be a proxy for sulfurized organic matter in organic-rich shales, particularly those prone to be siliceous or carbonate. First part uses a theoretical model of a compositional system consisting solely of iron, sulfur, TOC, and pyrite to demonstrate how the Fe/S ratio can indicate the presence of sulfurized organic matter using the model’s assumption of sulfur [...]
Climate resilience from long-term low till adoption in US farms
Published: 2026-10-04
Subjects: Agriculture, Environmental Sciences, Life Sciences, Physical Sciences and Mathematics, Sustainability
Low-intensity tillage (low till) has expanded rapidly in the United States since 2000. Evidence on its yield impacts has come mainly from field experiments and has been limited to short time horizons. Using satellite-based observations from more than 40 million field-year pairs across the U.S. Corn Belt from 1999-2023, we demonstrate that yield gains continue to accrue with longer duration of [...]