Preprints
Filtering by Subject: Oceanography
The Unfinished Map: Observing the Indian Ocean through Model-Corrected, Fleet-Based Sensing
Published: 2026-08-04
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Oceanography
We make decisions about the ocean-the largest and most consequential system on Earth-from a sample so sparse it would be judged inadmissible in almost any other science. Less than one-thousandth of one percent of the deep seafloor has ever been seen by a human eye or camera; most deep-ocean observation has been carried out by a handful of wealthy nations; and the Indian Ocean-which has absorbed a [...]
SCI-VIS: Lightweight Visibility Tagging for Coastal Camera Monitoring
Published: 2026-07-29
Subjects: Atmospheric Sciences, Environmental Monitoring, Oceanography, Remote Sensing
Automated assessment of imaging conditions is a necessary pre-processing step for any computer vision pipeline deployed on outdoor cameras subject to atmospheric variability. We describe SCI-VIS, a lightweight per-frame visibility classifier deployed within the Surfline Coastal Intelligence (SCI) pipeline. The Surfline coastal-camera network spans ~1,200 cameras worldwide. SCI-VIS tags each [...]
SCI-OBS: Detection and Classification of People on the Beach and in the Surf Zone
Published: 2026-07-28
Subjects: Environmental Monitoring, Natural Resources Management and Policy, Oceanography, Remote Sensing
Understanding how many people use beaches and surf zones is vital for safety, tourism, and coastal management. Traditional manual headcounts are time-consuming and inconsistent, while existing automated systems often fail in complex conditions due to glare, waves obstructing the view, and the small apparent size of distant subjects. We present SCI-OBS, an automated multi-class detector deployed [...]
Glycerolipids track sinking particle sources and remineralization in two ocean basins
Published: 2026-07-15
Subjects: Biogeochemistry, Geochemistry, Oceanography
The biological carbon pump is a major control on ocean carbon storage. On long time scales, changes in the biological carbon pump modulate atmospheric CO2 concentrations and climate. Attenuation in sinking carbon fluxes is derived from a combination of remineralization by bacteria, zooplankton, and fragmentation. However, the importance of these attenuation processes varies spatially and [...]
A machine learning approach for detecting biofouling in oceanographic data
Published: 2026-07-11
Subjects: Artificial Intelligence and Robotics, Fluid Dynamics, Numerical Analysis and Computation, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Autonomous ocean observing platforms collect long-term biogeochemical time series, but sensor degradation from biofouling introduces progressive biases that contaminate the climate record. This work focuses on the BGC-Argo fleet of profiling floats, where optical sensors measuring chlorophyll-a and backscatter are particularly susceptible to biofouling. Current detection relies on per-float [...]
A State-dependent Error Covariance Model of Surface Atmospheric Forcings over the Arctic Sea Ice
Published: 2026-07-01
Subjects: Atmospheric Sciences, Meteorology, Oceanography, Other Oceanography and Atmospheric Sciences and Meteorology
This paper presents a state-dependent error covariance model of surface atmospheric forcings over Arctic sea ice for constraining atmospheric influences on short-range sea ice forecast errors. Atmospheric influences are argued to be a dominant source of sea ice forecast errors at shorter lead times and thus need to be properly accounted for in generating ensemble sea ice forecasts relevant for [...]
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 [...]
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 [...]
Dress Rehearsal: 2023 El Niño Anticipatory Action Somalia, in the Shadow of 1997
Published: 2026-06-10
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Environmental Studies, Human Geography, Meteorology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Other Geography, Physical and Environmental Geography
In 2023 Somalia saw the largest-ever scale of anticipatory action (AA) linked to a seasonal forecast. $24m was spent on preparedness and early response, based on forecasted flooding driven by El Niño and a positiveIn 2023 Somalia saw the largest-ever scale of anticipatory action (AA) linked to a seasonal forecast. $24m was spent on preparedness and early response, based on forecasted flooding [...]
Hydroelectric Regulation Decouples Arctic Silica Delivery from the Diatom Bloom: A Climate-Independent Causal Attribution Across Twenty Subarctic Rivers
Published: 2026-05-23
Subjects: Earth Sciences, Hydrology, Oceanography, Physical Sciences and Mathematics
Large subarctic rivers deliver most of their dissolved nutrients during the spring freshet, in approximate phase with the ice-edge diatom bloom that those nutrients support. Hydroelectric regulation flattens the river hydrograph, holding back the freshet and raising winter discharge, and in doing so it redistributes nutrient delivery in time. Across twenty subarctic rivers spanning the Arctic [...]
Transformation of climatologically anomalous water masses
Published: 2026-05-15
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
We derive a novel anomalous water mass budget framework in which water masses are defined by bounds on tracer anomalies rather than absolute tracer values, extending Water Mass Transformation (WMT) theory to ocean variability and extremes. The material derivative of tracer anomalies introduces three additional transformation terms absent from the standard WMT framework: advection of [...]
Learning unresolved coastal dynamics in hydrodynamic models
Published: 2026-05-02
Subjects: Fluid Dynamics, Oceanography
Coastal hydrodynamic models play a vital role in understanding and predicting flooding, but practical computational constraints and uncertainties in boundary conditions and bathymetry lead to systematic errors in local sea level. We show that much of this error is not random but reflects a stable, site-specific response that can be learned from model output and observations. We develop a [...]
Why the Cap-Ferret sand spit is collapsing
Published: 2026-04-27
Subjects: Geomorphology, Hydrology, Oceanography, Sedimentology
The Cap-Ferret sand spit (SW France) exhibits a pattern of coastal instability that combines chronic shoreline retreat (8.7 m·yr⁻¹ at the tip, Robinet et al. 2025), sudden vertical collapses of emplaced structures (WW2 blockhaus 2024, 2026; oyster-farm sector 1936, 1977; Hortense promenade 1999, 2000, 2014, 2019), and progressive deepening of submarine pits (Hortense-Pointe depression volume [...]
Spatiotemporal evolution of temperature extremes across India’s agro-climatic zones (1951–2025)
Published: 2026-04-11
Subjects: Atmospheric Sciences, Climate, Meteorology, Oceanography
Long-term changes in temperature extremes are a robust signature of anthropogenic climate change, yet their spatial structure across India’s agro-climatic zones (ACZs) remains insufficiently resolved at policy scales. Here, we quantify changes in temperature extremes across 14 mainland ACZs during 1951–2025 using the India Meteorological Department 1°×1° gridded daily dataset. We compute 22 [...]