Preprints
Filtering by Subject: Physical Sciences and Mathematics
Underestanding Tipping Points Caused by Climate Change in Iran: A review
Published: 2026-06-19
Subjects: Physical and Environmental Geography, Physical Sciences and Mathematics
Climate tipping points are caused by global warming and refer to critical thresholds in the climate system, crossing which leads to irreversible changes in climate conditions, ecosystems, and even socio-economic structures. These changes may occur over long time scales, ranging from several decades to hundreds of years, and their effects are often negative and threatening, although some positive [...]
Regional anthropogenic aerosol reductions amplify probability of record-breaking heat extremes
Published: 2026-06-18
Subjects: Physical Sciences and Mathematics
Record-breaking heat extremes are becoming more likely due to anthropogenic climate change, with their probability depending on the regional warming rate. Anthropogenic aerosol forcing modulates these warming rates, and aerosols are declining globally. However, the influence of aerosols on the probability of record-breaking heat extremes remains unclear. Here, we assess how aerosol trends alter [...]
Linking double seismic zones to oceanic lithosphere rheological layering: the role of mid-lithospheric discontinuities
Published: 2026-06-18
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics
The origin of the ubiquitous lower seismic layer (LSL) in double seismic zones (DSZs) within subducting oceanic lithosphere remains one of the most persistent unresolved problems in subduction-zone seismicity. Analysis of recent geophysical observations reveals a close spatial association between the LSL and the oceanic mid-lithospheric discontinuity (MLD), a feature attributed to the [...]
Seismic Evidence for an Ultralow Velocity Zone Beneath the Cape Verde Hotspot
Published: 2026-06-17
Subjects: Physical Sciences and Mathematics
Mega ultralow velocity zones (mega-ULVZs), thin patches of strongly reduced seismic velocity with large horizontal extent just above the core-mantle boundary (CMB), are increasingly found beneath deep mantle plumes, suggesting a link to hotspot volcanism. The Cape Verde hotspot is thought to overlie a deep plume, but whether a ULVZ exists at its base has remained unknown. We present [...]
Tropical cyclones intensify mesoscale eddy variability and accelerate Western Boundary Current instability
Published: 2026-06-17
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Tropical cyclones strongly disrupt the upper ocean, yet their influence on mesoscale variability in western boundary current systems remains poorly quantified. The Gulf of Mexico, where the Loop Current regularly sheds large warm-core eddies, offers an ideal setting to examine how hurricanes reshape mesoscale dynamics. Using a high-resolution ocean model and hurricane-denial experiments, we [...]
ENSO-Driven Modulation of the Caribbean Subsurface Salinity Maximum
Published: 2026-06-16
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
This study identifies El Niño–Southern Oscillation (ENSO) as the primary driver of interannual subsurface salinity variability in the Caribbean Sea. Using 30 years of high-resolution, data-assimilative ocean reanalysis (1993–2022), we show that the Subsurface Salinity Maximum (SSM) closely tracks ENSO cycles: El Niño events correspond to a saltier and deeper SSM, while La Niña drives a fresher [...]
Internal Processes Driving the Slow-to-Fast Transition of a Rockslide
Published: 2026-06-16
Subjects: Physical Sciences and Mathematics
Landslides may creep slowly for decades to centuries under external influences such as rainfall or seismic shaking. Predicting when and how they transition into catastrophic acceleration remains a major challenge because the internal processes driving failure occur at depth and are often not evident from surface observations alone. Here, we combine local seismic and geodetic measurements to [...]
Why the Earth Exhibits Interhemispheric Albedo Symmetry: Erosion–formation asymmetry of low-cloud responses to circulation reorganization.
Published: 2026-06-16
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Earth exhibits a striking near symmetry in interhemispheric mean albedo despite substantial asymmetries in surface properties, aerosols, and geography. Whether this symmetry is coincidental or dynamically constrained remains unresolved. Here we present a minimal theoretical framework showing that a moist atmosphere provides a physically constrained, but bounded, tendency to oppose [...]
Samoa Basin Abyssal Mapping: Box Coring Leg
Published: 2026-06-15
Subjects: Physical Sciences and Mathematics
This cruise report describes work from leg three of the NOAA American Samoa Abyssal Mapping effort, OPR-T900-KR-26. Leg one preceded this effort and collected ship-based acoustic data. Leg two collected autonomous underwater vehicle (AUV) data and began before, continued contemporaneously, and finished subsequently to leg three. The USGS field activity number assigned to this expedition is [...]
Condensation Radiation of Water Vapor Drives Diurnal Temperature Range Patterns
Published: 2026-06-15
Subjects: Physical Sciences and Mathematics
The global distribution and variation of the Diurnal Temperature Range (DTR) remain “an essential knowledge gap” in our understanding of climate dynamics in IPCC assessment reports. This study introduces the radiative mechanism of water vapor condensation as a novel physical driver of DTR dynamics. Contrary to classical heat conduction theory, which assumes latent heat transfers via temperature [...]
Deglacial reconstruction of the spatial extent and intensity of the North Atlantic Subtropical High
Published: 2026-06-13
Subjects: Climate, Physical Sciences and Mathematics
Rainfall-related hazards are growing in southeastern North America (SENA) but well-documented climate-model biases cast doubt on projected rainfall changes. The North Atlantic Subtropical High (NASH) supplies the moisture that drives extreme rainfall in SENA, so reconstructing its past behavior offers a test of model fidelity. Using the hydrogen-isotope composition of leaf-wax biomarkers (δDwax) [...]
Warming above, cooling below: First model-based quantitative thermal- regime assessment and subsurface thermal evolution of Nivlisen Ice Shelf, East Antarctica, revealing non-equilibrium thermal adjustment and progressive thermal preconditioning
Published: 2026-06-13
Subjects: Physical Sciences and Mathematics
We present the first quantitative thermal characterisation of Nivlisen Ice Shelf, central Dronning Maud Land, East Antarctica, using a one-dimensional heat-transfer model forced by ERA5 surface skin temperatures (1940–2025). For the primary scenario (H = 312 m), the steady-state solution yields a mid-column temperature of −4.89 °C, Péclet number Pe = 4 (intermediate conduction–advection regime), [...]
PIKART Version 1.1: Release Notes
Published: 2026-06-12
Subjects: Physical Sciences and Mathematics
The PIK Atmospheric River Trajectories (PIKART) catalog is a global, high-resolution catalog of atmospheric rivers (ARs). Version 1.1 (v1.1) addresses two algorithmic bugs present in version 1.0 (v1.0): a boundary artifact at 30°E emerging during the extraction of the background component of the integrated vapor transport (IVT), and an error in the AR tracking algorithm that affected the [...]
Novel Data-driven High-Frequency Mass Change Models from GRACE orbit residuals
Published: 2026-06-11
Subjects: Climate, Earth Sciences, Fresh Water Studies, Glaciology, Hydrology, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Other Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
We present a fully data-driven framework for transforming residual K-band range-rate (KBRR) data from GRACE into 5-day mass change models expressed in Equivalent Water Height (EWH). The approach first derives residual range and Line-of-Sight Gravity Differences (LGDs) from monthly post-fit residual range-rates and combines them with 5-day post-fit residuals. A hybrid formulation, merging LGD- and [...]
Seeing Cities in Depth: Subsurface Urban Expansion and the Case for Volumetric Monitoring and Accountability
Published: 2026-06-10
Subjects: Physical Sciences and Mathematics, Social and Behavioral Sciences
Urban science can measure surface and aboveground change with increasing precision. Satellites, building-footprint datasets, and emerging three-dimensional products now track urban land, building height, and built volume. Yet these tools still struggle to capture urbanization below ground. This Perspective defines subsurface urban expansion as the extension of urbanization below the local ground [...]