Preprints
There are 7853 Preprints listed.
Same computation, different scenes: a single-site comparison of Sentinel-2 L2A composites from Google Earth Engine and Microsoft Planetary Computer
Published: 2026-10-18
Subjects: Earth Sciences, Environmental Sciences
Google Earth Engine (GEE) and Microsoft Planetary Computer (MPC) distribute Sentinel-2 Level-2A surface reflectance, and their outputs can be combined in one time series. Over a 73 ha cattle farm in northern Colombia, we tested whether the two platforms yield the same parcel-scale vegetation and water indices and, where they differ, whether the difference originates in the product (the L2A [...]
Semi-analytic reference solutions for 3D controlled-source electromagnetics: a conductive sphere beneath Gaussian topography in a layered earth
Published: 2026-10-18
Subjects: Geophysics and Seismology
Three-dimensional forward codes for controlled-source and transient electromagnetics are verified mostly by comparison with one another when the model contains topography and a compact body in a layered host. We present terrasphere_csem, an open-source semi-analytic reference for this coupled problem. A Gaussian hill or depression forms the surface of a horizontally layered earth, and a [...]
Multi-objective optimisation of natural flood management for community-level property damage reduction using a physically based distributed hydrological model
Published: 2026-10-18
Subjects: Engineering
Natural flood management (NFM) at the catchment scale requires cost-effective spatial configurations that maximise flood risk reduction while minimising implementation cost. Existing studies often assess predefined scenarios at catchment outlets, limiting systematic portfolio evaluation and community-scale impact assessment. This study couples the fully distributed, physically based SHETRAN [...]
Leveraging satellite data and machine learning to quantify rooftop rainwater harvesting reliability and tank requirements for schools and health care facilities in Uganda
Published: 2026-10-18
Subjects: Civil and Environmental Engineering, Earth Sciences, Environmental Engineering, Environmental Sciences, Geography, Hydrology, Remote Sensing, Water Resource Management
Many schools and health facilities in Uganda lack a reliable water supply, yet most have roofs that could collect rain. For 41,592 facilities (32,881 schools and 8,711 health facilities), we estimated how much water their roofs can supply, how large a tank each one needs, and how often that supply fails. Roof areas came from AI-derived building footprints (Google Open Buildings v3) and daily [...]
Synergistic Use of Multitemporal SAR and Optical Data with Random Forest Approach for Rice Mapping in Bangladesh
Published: 2026-10-18
Subjects: Physical Sciences and Mathematics
Accurate in-season crop mapping is vital for national food security, yet traditional ground-based estimation methods in Bangladesh often lack precision. This study develops a robust machine-learning framework to map Boro rice in the Manikganj district by integrating Sentinel-1 Synthetic Aperture Radar (SAR) and Sentinel-2 optical imagery. To overcome the challenge of seasonal cloud cover, [...]
Why Bandung heard the September 2026 Anak Krakatau eruption and Jakarta did not: eruption timing, ray tracing and search-interest evidence, compared with April 2020
Published: 2026-10-17
Subjects: Atmospheric Sciences
During the night of 4–5 September 2026, residents of the Bandung area, 240–300 km from Anak Krakatau, reported repeated booms and rattling windows, while Jakarta, 150 km from the volcano, reported almost none. The Indonesian meteorological agency (BMKG) first judged the volcano too distant and the winds unfavourable, then attributed the booms to the eruption. We test the volcanic explanation with [...]
Paraglider flight logs as hypsometers: daily temperature profiles of an Alpine valley, its diurnal heating, and the nearly level ceiling of thermals
Published: 2026-10-17
Subjects: Atmospheric Sciences, Meteorology, Oceanography and Atmospheric Sciences and Meteorology
A paraglider flight recorder writes a barometric and a GNSS altitude every second. Between two pressure levels, the difference in GNSS altitude is the thickness of the layer, set by its mean virtual temperature: each recorder is a hypsometer, and a fleet of them a sounding network over every flown slope. Applied to 31 677 logs from dedicated instruments in the Valais, Swiss Alps, the method [...]
Long-term increases in station-derived drought near Apalachicola National Forest, Florida
Published: 2026-10-16
Subjects: Physical Sciences and Mathematics
Long local weather records can reveal changes in drought exposure, but a drought index calculated at one station must be distinguished from soil-water measurements across a forest. We updated daily temperature and precipitation observations at Tallahassee airport and recomputed the Keetch-Byram Drought Index (KBDI) with explicit quality control, rainfall interception, and missing-data rules. [...]
Earth's Bad Decades: A Sedimentary Record of the Chicxulub Aftermath from the New Jersey Coastal Plain and Offshore
Published: 2026-10-16
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Sedimentology, Stratigraphy
The New Jersey Coastal Plain (NJCP) preserves records of the Chicxulub impact approximately 2,500 km from the crater, providing a unique archive of ejecta fallout, sediment reworking, ecological disruption, and recovery following the end-Cretaceous mass extinction. Preservation of impact deposits varies with depositional setting. Offshore sections beneath the NJ continental shelf and slope [...]
Monitoring Carbon Hotspots in Patchy Landscapes from Sparse Lidar and Dense Satellite Time Series
Published: 2026-10-16
Subjects: Environmental Indicators and Impact Assessment, Environmental Monitoring, Natural Resources and Conservation, Natural Resources Management and Policy
Monitoring aboveground biomass (AGB) stocks as an indicator of carbon storage is essential for climate mitigation, adaptation, and land management. Across much of Earth’s land surface, carbon stocks are concentrated in fine-scale hotspots, including isolated trees in pastures, shrub patches in tundra, and riparian vegetation in drylands. These carbon hotspots are vulnerable to change but are [...]
Using Global Climate Models to Inform Multi-Driver Biological Ocean Experiments
Published: 2026-10-16
Subjects: Biogeochemistry, Oceanography
This century, widespread shifts in temperature and CO2-driven acidification are projected for the surface ocean. Determining how ocean biota will respond to these changes requires scaling multiple drivers together because biological responses to one driver often depend on the conditions of the others. However, ocean temperature and carbonate chemistry vary across regions, seasons, and emissions [...]
A Community-Oriented Flood Map Visualization and Evaluation Framework
Published: 2026-10-16
Subjects: Civil and Environmental Engineering, Computer Engineering, Computer Sciences, Engineering, Hydraulic Engineering, Hydrology, Software Engineering
Flood inundation maps are essential for preparedness, response, and long‐term risk mitigation, yet many existing visualization platforms remain limited by rigid data structures and region‐specific workflows. This study introduces FIMApp, a client‐side, web‐based framework and platform for integrating, visualizing, and comprehensively evaluating flood map products using standardized, portable data [...]
Paragliders as probes of the Alpine boundary layer: sink polars from 86 000 flight logs and the flow field of a valley
Published: 2026-10-15
Subjects: Atmospheric Sciences, Fluid Dynamics, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics
Paraglider flight logs are a dense, free and continuous record of the air over mountains: every thermal day, hundreds of pilots fly for hours along the slopes and across the valleys and record their vertical speed once per second. The obstacle is that a vario measures the air plus the sink of the glider, and the sink polars of paragliders are unknown. We obtain them from the logs themselves. [...]
Characteristics and consequences of H2O undersaturation and low melt fertility in mountain belt interiors
Published: 2026-10-15
Subjects: Earth Sciences, Geology, Tectonics and Structure
Continental deformation and crustal magmatism in orogenic settings are fundamentally linked to fluid availability and melting processes. Critical rheological transitions occur at approximately 7% melt volume, whereby melt-film connectivity reduces rock strength by as much as c. 90%, and at 20%, marking an onset of solid-to-liquid behaviour. The Mesoproterozoic Grenville orogen in Canada provides [...]
A steadily flowing glacier and no detectable precursor before the 11 October 2026 Budhi Gandaki rock–ice avalanche and flood, Nepal
Published: 2026-10-15
Subjects: Earth Sciences, Geomorphology
On 11 October 2026 at about 04:20 local time, a rock–ice avalanche at the head of the Ungilung Khola, on the southern slopes of Chamar (7,165 m) in Gorkha District, Nepal, became a debris flow and flood that travelled down the Syar Khola and the Budhi Gandaki. I reconstruct the event from free satellite data (Sentinel-1, Sentinel-2, Landsat 8/9, ITS_LIVE and NISAR), official records and my own [...]