Preprints
Filtering by Subject: Hydrology
Toward Fit-for-Purpose Evapotranspiration Observations
Published: 2026-06-20
Subjects: Atmospheric Sciences, Earth Sciences, Hydrology, Oceanography and Atmospheric Sciences and Meteorology
Evapotranspiration (ET) underpins water, energy, and carbon cycling, yet remains among the least observed hydrologic fluxes, creating a persistent paradox: hydrology is advancing rapidly through artificial intelligence and data-driven methods while its observational foundation remains sparse and fragmented. Eddy covariance provides robust ET measurements, but high cost and operational demands [...]
Global Gravitational-Resonant Waves in the Arctic Basin: Visualizing Hidden Ocean Macrodynamics using 22-Year Passive Microwave Radiometry Data
Published: 2026-06-20
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Hydrology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology
The dynamics of the Arctic Ocean's sea ice cover are traditionally viewed through the lens of atmospheric forcing, ocean currents, and thermodynamic processes. In this paper, we propose a fundamentally new paradigm: the sea ice cover acts not as an elastic membrane transmitting mechanical stress, but as a passive two-dimensional indicator (analogous to Chladni figures) that visualizes a [...]
Mixing-Limited Effective Reaction Rates in Porous Media: An Explicit Prediction from Pore-Scale Mixing
Published: 2026-06-14
Subjects: Geochemistry, Hydrology
Two solutes can share the same volume of a porous medium and still barely react, because sharing a volume is not the same as mixing. As the flow carries them, it stretches each into thin filaments that interleave through the pore space, and reaction is confined to the narrow fronts where those filaments meet. A continuum model that simply multiplies the average concentrations ignores this and [...]
Novel Data-driven High-Frequency Mass Change Models from GRACE orbit residuals
Published: 2026-06-12
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 [...]
High-resolution monthly sectoral water demands for the U.S. over 1980-2100
Published: 2026-06-11
Subjects: Civil Engineering, Hydrology, Water Resource Management
U.S. water demand varies sharply by sector and region as land use, population, weather patterns, and economic activity co-evolve. High-resolution water demand data are required to capture these dynamics and to support integrated energy-water-land modeling and local-to-regional water scarcity assessments. We present a gridded (1/8$^{\circ}$), monthly, multi-sector water demand dataset for the [...]
Reactive soil inputs during high-flow events decouple carbon chemistry and CO2 evasion in a granitic headwater stream
Published: 2026-06-11
Subjects: Biogeochemistry, Hydrology
Quantifying CO2 dynamics in low-alkalinity headwater streams is challenging because thermodynamically based evaluations of pCO2 and CO2 fluxes (FCO2) assume coherent DIC-alkalinity-pH coupling. This study examines how hydrologically driven disturbances violate this assumption in a forested, granitic headwater stream using 15 months of calculated pCO2 and FCO2, alongside measurements of pH, [...]
A satellite-monitoring research agenda for urban stormwater infrastructure: capabilities, gaps, and a community-benchmark proposal
Published: 2026-06-09
Subjects: Environmental Engineering, Hydraulic Engineering, Hydrology
Urban stormwater best management practices (BMPs) are a core component of urban-resilience portfolios worldwide. Per-asset performance monitoring, however, is both limited and difficult to enumerate at the global scale. We argue that publicly available satellite Earth observation has reached the capability point at which the resulting accountability gap can be closed at portfolio scale, and that [...]
Simulations of Minnesota water budget components using the Soil-Water-Balance model, past (1981–2022) and future (2040–59 and 2080–99)
Published: 2026-06-09
Subjects: Climate, Hydrology, Water Resource Management
This study presents historical estimates and future projections of net infiltration (potential recharge), actual evapotranspiration (ET), surface runoff, and related water budget components across Minnesota using the USGS Soil Water Balance model, version 2 (SWB). The model was calibrated to streamflow and actual ET observations from 2000–2022, achieving an overall r² of 0.973 with a standard [...]
A Fibonacci-Like Propagation Graph for Infiltration and Internal Erosion in Heterogeneous Layered Soils
Published: 2026-06-06
Subjects: Geotechnical Engineering, Hydrology, Numerical Analysis and Scientific Computing, Soil Science
Infiltration and internal erosion in heterogeneous layered soils involve coupled flow, pressure build-up, and material degradation across preferential subsurface pathways. High-fidelity Richards-type simulators are physically detailed but can be too expensive for rapid scenario screening and Monte Carlo uncertainty propagation when hydraulic parameters are poorly constrained. We introduce a [...]
Empirical constraints on the fraction of surface latent heat flux reaching the top of atmosphere as net radiative cooling
Published: 2026-06-04
Subjects: Atmospheric Sciences, Climate, Hydrology
The transfer fraction η, defined as the ratio of net cloud radiative effect at the top of atmosphere to surface latent heat flux (η = |CRE_net| / LE), is a fundamental coupling parameter linking surface hydrology to TOA radiation. Despite its relevance to cloud feedback and biophysical forcing, η has not been directly constrained by co-located observations at the spatial scales relevant to [...]
Comparing Process-Based and Machine Learning Models for Streamflow Prediction in the Kaligandaki River Basin, Nepal
Published: 2026-06-04
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Hydrology, Physical Sciences and Mathematics, Water Resource Management
Reliable daily streamflow prediction is critical for hydropower operations, flood risk management, and irrigation planning in monsoon-dominated Himalayan river basins. While both process-based and machine learning (ML) approaches have been used for such tasks, systematic comparisons that decompose the sources of performance differences remain scarce. This study evaluates seven configurations: a [...]
Engineering AI-Assisted Client-Side Scientific Workflows: WebGPU Inference Architecture and Framework for Privacy-Preserving Hydrological Analysis
Published: 2026-05-30
Subjects: Artificial Intelligence and Robotics, Environmental Sciences, Hydrology, Software Engineering
Deep learning has demonstrated strong potential for improving hydrological predictions, yet its practical adoption remains limited by software complexity, infrastructure requirements, data governance constraints, and fragmented analytical workflows. This study presents Hydro AI Lab, an AI-assisted client-side scientific workflow platform that enables end-to-end hydrological analysis, including [...]
Extreme changes in water level regenerate reed stands and a stable water regime leads to die-off: lessons from the analysis of 40-year satellite time series observations in a shallow lake ecosystem.
Published: 2026-05-30
Subjects: Earth Sciences, Ecology and Evolutionary Biology, Hydrology, Natural Resources and Conservation, Physical Sciences and Mathematics, Terrestrial and Aquatic Ecology, Water Resource Management
Reed wetlands are key to the productivity of shallow lakes, and their condition is tightly governed by water level variability. Using long-term satellite observations, we provide the first analysis linking hydrology and reed vitality at Lake Neusiedl, a major climate sensitive wetland system in the Pannonian Basin. We assembled a 40-year record (1985–2025) of Landsat derived Enhanced Vegetation [...]
HydroModelSpec: Toward Standardized Machine Learning Model Exchange in Hydrology
Published: 2026-05-30
Subjects: Environmental Sciences, Hydrology, Software Engineering
The rapid growth of deep learning models for hydrological forecasting (e.g., CNNs, LSTMs, Transformers) has created a fragmented ecosystem where trained models remain tied to their original frameworks, environments, and institutions. Despite substantial investments in model development, the hydrological community lacks a generalized structure for packaging models with their architecture, training [...]
ENSO Modulation of the Amazonian Low-Level Jet: More Moisture, Less Rain, and the Role of Land Surface Reception
Published: 2026-05-30
Subjects: Climate, Hydrology, Meteorology
The Amazonian Low-Level Jet (ALLJ) carries moisture from the tropical Atlantic coast into the basin interior, sustaining wet-season convection. Here we analyze 45 years of ERA5 reanalysis (1979–2023), 44 years of CHIRPS precipitation (1981–2024), GRACE terrestrial water storage (2002–2025), and SMAP root-zone soil moisture (2015–2024) to determine how ENSO modulates this transport pathway and its [...]