Preprints
Filtering by Subject: Physical Sciences and Mathematics
Daily Flood Mapping at 90 m Resolution Through Physically-Constrained CYGNSS–SAR Fusion
Published: 2026-09-11
Subjects: Physical Sciences and Mathematics
Satellite flood mapping faces a fundamental spatiotemporal trade-off: Synthetic Aperture Radar (SAR) missions provide high-resolution flood masks but revisit any given location only every 6–12 days, while GNSS Reflectometry observations from the CYGNSS constellation are available daily but at kilometer scale. Neither sensor alone suffices to track flood events evolving over 24–72 hours. We [...]
Reconstructing annual 30 m forest aboveground biomass across Southwest China’s karst region from 1986 to 2024
Published: 2026-09-10
Subjects: Engineering, Life Sciences, Physical Sciences and Mathematics
Fine-resolution reconstruction of multi-decadal forest aboveground biomass (AGB) remains challenging in karst landscapes, where steep terrain, fragmented stands, and strong environmental gradients can limit the regional transferability of national and global products. We developed a regionally adapted two-stage framework to reconstruct annual 30 m forest AGB across Southwest China’s karst region [...]
The explosive engine of the 2022 Hunga submarine eruption
Published: 2026-09-10
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Volcanology
The 2022 submarine eruption of Hunga volcano, Tonga, was among the largest volcanic eruptions in the modern era, yet the processes controlling its explosive sequence remain poorly understood. Here we present the first detailed insight into the internal mechanics of an explosive cycle from teleseismic waveforms. Four eruptive episodes repeat an implosion-explosion cycle, separated by a 3-minute [...]
Reactive halogens drive rapid mercury oxidation in hot volcanic emission-plumes
Published: 2026-09-09
Subjects: Physical Sciences and Mathematics
Volcanoes release mercury (Hg) alongside gases and particles through continuous passive degassing and by explosive and effusive eruptions. The global dispersion and environmental impact depend on volcanic Hg oxidation state, which remains poorly constrained: thermochemical calculations of magmatic gas composition and crater-rim sampling indicate Hg to be predominantly in the reduced Hg0 form that [...]
Dendrochronology and the date of the Thera volcanic eruption
Published: 2026-09-07
Subjects: Earth Sciences, Glaciology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology, Volcanology
The main disciplines that contribute to our understanding of the chronology of the ancient Near East are history, archaeology, and various scientific dating techniques including dendrochronology, radiocarbon dating, and ice-core analysis. Beginning in the 1980s, a major rift began to develop between the historical-archaeological chronology and that based on dendrochronology-calibrated radiocarbon [...]
A Changing North Atlantic Background Amplifies Western European Heatwaves
Published: 2026-09-06
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Western European summer heatwaves have increased markedly since the 1990s, culminating in the record warmth of May–July 2026 since 1950. We show that this rise is closely associated with the slowly evolving North Atlantic background. We combine two leading April sea surface temperature modes, representing basin-wide warming and a tripole-like pattern, into an Atlantic Two-Mode Index (ATMI). The [...]
Station spacing bounds the recovery of rainfall extremes by interpolation: an independent-network test with consequences for landslide thresholds
Published: 2026-09-06
Subjects: Physical Sciences and Mathematics
Gridded rainfall products interpolated from gauge networks underpin landslide early warning, and a common view holds that their main deficiency in mountains is the omission of orographic enhancement. This study tests that view using an independent network: 464 mountain stations operated by the Korea Forest Service that do not enter the operational grid of the Korea Meteorological Administration. [...]
A Unified Forearc Subsidence Model Based on the Three-Arc Unjoined Structure of the Honshu Arc
Published: 2026-09-06
Subjects: Physical Sciences and Mathematics
This study reinterprets the subsidence, uplift, fault activity, and geomorphic development observed in the Nōbi Plain, Ise Bay, Lake Biwa, Wakasa Bay, and Osaka Bay through a new structural framework in which the Honshu Arc is understood as an incompletely joined system of three arcs. The Southwest Japan Arc (narrow sense), the Hida–Tamba Terrane, and the Northeast Japan Arc approached each other [...]
Systematic Evaluation of a Transformer-Based Surrogate for Distributed Groundwater Dynamics: Long-Horizon Prediction, Dynamic–Static Fusion, and Data Augmentation
Published: 2026-09-05
Subjects: Engineering, Physical Sciences and Mathematics
Transformers are increasingly reshaping artificial-intelligence-based Earth system prediction, yet their suitability for distributed groundwater surrogate modeling remains poorly understood. Groundwater dynamics combine strong temporal persistence with spatial interactions governed by heterogeneous hydrogeological conditions. These characteristics make attention-based architectures potentially [...]
Earthquakes prime landscapes for typhoon-induced permeability loss
Published: 2026-09-04
Subjects: Physical Sciences and Mathematics
Bedrock aquifers supply drinking water to half the global population, and earthquakes can disrupt this resource for years by changing their permeability. Previous studies proposed several mechanisms to explain coseismic permeability changes but lacked an observational tool to distinguish them; moreover, all assumed an immediate onset. Here, we analyse groundwater and seismic data from eastern [...]
Isochrone overturning in steady glacier flow
Published: 2026-09-04
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Ancient ice recovered at Allan Hills extends into the Miocene, but steep layers, age reversals and folds complicate its interpretation. Whether steady glacier flow can overturn initially ordered layers remains uncertain. Here, we track the horizontal order of particles deposited sequentially at the surface. This order is measured by a signed Jacobian that is equivalent to the inverse [...]
Simulation analysis method of drainage system of tideland paddy zone
Published: 2026-09-03
Subjects: Physical Sciences and Mathematics
The tideland paddy zone drainage system plays an important role in preventing flood damage and protecting the tideland paddy zone by draining the rainwater from the paddy zones and the surrounding catchments in good time. Therefore, scientific design of drainage system and accurate assessment of drainage capacity in tideland paddy zones are important for sustainable development in agricultural [...]
Modelling Winter Atmospheric River Frequency over the Western Himalayas Using Large-Scale Climate Modes Via Statistical Approach
Published: 2026-09-03
Subjects: Engineering, Physical Sciences and Mathematics
Winter Atmospheric Rivers (ARs) contribute substantially to precipitation in the Western Himalayas, but how large-scale climate modes jointly influence their frequency remains unclear. In this study, we use a statistical method that combines correlation, phase-composite analysis of Integrated Vapor Transport (IVT), and predictive models such as linear regression, Generalized Linear Models (GLMs), [...]
The importance of ice shelf melt rate distributions in modelling of Antarctic ice loss
Published: 2026-09-03
Subjects: Environmental Sciences, Glaciology, Oceanography, Physical Sciences and Mathematics
Ocean-induced basal melting of ice shelves is a major cause of Antarctic ice loss. It is well known that the magnitude of this melt is an important factor to consider when modelling the future evolution of the ice sheet, and values of total melt volume or mean melt rates are often quoted for ice shelves. The finer detail of the distribution of this melt is usually given less attention. Here we [...]
Fault roughness as a driver of rupture complexity in fluid-induced microearthquakes
Published: 2026-09-03
Subjects: Physical Sciences and Mathematics
Subsurface fluid-injection can induce microearthquakes whose rupture complexity and arrest mechanisms remain poorly understood, limiting our ability to assess the seismic hazard associated with geo-energy applications. We investigate how fault roughness modulates the response of fluid-pressurized faults using an ensemble of 1395 3D dynamic rupture simulations on self-similar rough faults, varying [...]