Evaluating High-Frequency radar data assimilation impact in coastal ocean operational modelling

Published: April 30, 2021

Abstract. The impact of the assimilation HFR (High-Frequency Radar) observations in a high-resolution regional model is evaluated, focusing on improvement mesoscale dynamics. study area Ibiza Channel, located Western Mediterranean Sea. resulting fields are tested against trajectories from 13 drifters. Six different experiments compared to control run (no assimilation). consists assimilating (i) Sea surface temperature, sea level anomaly and Argo profiles (generic observation dataset); generic dataset plus (ii) total velocities (iii) radial velocities. Moreover, for each two initialization methods assessed: a) restarting directly analysis after or b) using an intermediate step applying strong nudging towards fields. with direct restart provides best results, improving by 53 % average separation distance between drifters virtual particles first 48 hours simulation comparison run. When step, results found when velocities, reduction mean around %. Results show capability Ensemble Optimal Interpolation data-assimilative system correct currents not only inside but also beyond coverage area. benefits smoothing effect associated application step.

Language: Английский

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Gulf of Naples Advanced Model (GNAM): A Multiannual Comparison with Coastal HF Radar Data and Hydrological Measurements in a Coastal Tyrrhenian Basin

Journal of Marine Science and Engineering, Journal Year: 2022, Volume and Issue: 10(8), P. 1044 - 1044

Published: July 29, 2022

High-resolution modelling systems have increasingly become an essential requirement to investigate ocean dynamics over a wide range of spatial and temporal scales, integrate the punctual observations. When applied in coastal areas, they also potential provide detailed representation transport exchange processes at sub-basin scale. This paper presents validation exercise between surface fields generated by regional modeling system (ROMS), developed for Tyrrhenian Sea downscaled Gulf Naples (GNAM advanced model), 4 year-long (2009–2012) record high-frequency radar (HFR) data. The comparison hourly seasonal model results HFR is focused on (GoN), where observational network three sites has been operational since 2004, specific subdomain characterized presence Sarno river, long-term ecological research station (LTER-MC) one important canyon area. An evaluation transect delimiting inshore–offshore zones GoN presented. GNAM was compared with situ hydrological parameters temperatures salinities retrieved LTER-MC fixed monitoring station. According skill metrics, basic circulation features are accurately reproduced model, despite some drawbacks terms increment energy content current field occurring during events. allow us identify errors suggest useful improvements, outcome confirms unique capability HF fine-scale measurements numerical models counterbalance lack high-resolution areas.

Language: Английский

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Assessment of OMA Gap-Filling Performances for Multiple and Single Coastal HF Radar Systems: Validation with Drifter Data in the Ligurian Sea

Remote Sensing, Journal Year: 2024, Volume and Issue: 16(13), P. 2458 - 2458

Published: July 4, 2024

High-frequency radars (HFRs) provide remote information on ocean surface velocity in extended coastal areas at high resolutions space (O(km)) and time (O(h)). They directly produce radial velocities (in the radar antenna’s direction) combined to total vector covered by least two radars. HFRs are a key element observing systems, with several important environmental applications. Here, we an assessment of HFR-TirLig network NW Mediterranean Sea, including results from gap-filling open-boundary modal analysis (OMA) using situ data drifters. While consists three radars, only were active during experiment, so test also includes area where one system available. The results, metrics, both Eulerian Lagrangian, configurations, show that performance is very satisfactory compares well previous literature terms coverage adequate, i.e., sampled Regarding OMA not do they perform equally but only. Even though obviously deteriorated respect case adequate coverage, can still regarding structure speed as virtual trajectories, which be some use practical A general discussion implications for potential sensing estimation HFR configurations complementing provided.

Language: Английский

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Evaluating altimetry-derived surface currents on the south Greenland shelf with surface drifters

Ocean science, Journal Year: 2023, Volume and Issue: 19(5), P. 1393 - 1411

Published: Sept. 21, 2023

Abstract. The pathways and fate of freshwater in the East Greenland Coastal Current (EGCC) are crucial to climate system. EGCC transports large amounts close proximity sites deep open-ocean convection Labrador Irminger seas. Many studies have attempted analyze this system from models various observational platforms, but modeling results largely disagree with one another, observations limited due harsh conditions typical region. Altimetry-derived surface currents, constructed remote-sensing applying geostrophic equations, provide a continuous data set beginning 1993. However, these products historically encountered difficulties coastal regions, thus their validity must be checked. In work, we use comprehensive methodology compare Eulerian Lagrangian 34 drifter trajectories demonstrate that altimetry-derived currents surprisingly capable recovering spatial structure flow field on south shelf can mimic nature as observed drifters.

Language: Английский

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LOCATE v1.0: Numerical Modelling of Floating Marine Debris Dispersion in Coastal Regions Using Nested Hydrodynamic Grids and Parcels v2.4.2

Published: Sept. 27, 2023

Abstract. The transport mechanisms of floating marine debris in coastal zones remain poorly understood, primarily due to the complex geometry and influence processes which pose difficulties incorporating them into Lagrangian numerical models at scales. model presented this study addresses these challenges using nested grids varying hydrodynamic resolutions (2.5 km, 350 m, 70 m). couples Eulerian data with a particle solver accurately simulate motion plastic particles regions. A validation was conducted drifter assess model’s skill confidence simulation predictions. results demonstrated high stability 72-hour forecast horizons score values close shoreline. Additionally, beaching sensitivity analysis performed determine parameterisations suitable for zones. This that real-time distance shore during simulations most accurate method detecting land-water boundary scales, representing residence times spatiotemporal patterns. Simulations were single coarse grid, both same input from river outflows pilot test Barcelona coastline morphology structures, two major mouths, large harbour. revealed marked differences amounts times. Both exhibited levels beaching, grid registering 91.5 % low-resolution showing 95.8 surpassing other studies larger Beaching variability within demarcated areas between simulations, highest flux observed near Llobregat River mouth release point. inner port area showed have 18 longer when high-resolution data, demonstrating ability solve geometrical structures. By grids, can resolve potential accumulation litter hot-spots

Language: Английский

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Hydrodynamic and Particle Drift Modeling as a Support System for Maritime Search and Rescue (SAR) Emergencies: Application to the C-212 Aircraft Accident on 2 September, 2011, in the Juan Fernández Archipelago, Chile

Journal of Marine Science and Engineering, Journal Year: 2022, Volume and Issue: 10(11), P. 1649 - 1649

Published: Nov. 3, 2022

Search and rescue (SAR) refers to every operation aiming find someone presumed lost, sick, or injured in remote hard-to-access areas. This study presents the design of an operational system that supports maritime SAR emergencies by combining information from global hydrodynamic models (GHM) a local model (LHM) implemented FVCOM. The output these is used as input multiple particle drift estimator (MPDE) estimate trajectories floating elements derived accidents ocean. MPDE also includes trajectory estimates using empirical LEEWAY formulation. modeling validated with data collected during emergency occurred on 2 September 2011, where C-212 aircraft Chilean Air Force destined Juan Fernández Archipelago crashed ocean between islands Santa Clara Robinson Crusoe. Trajectories were assessed terms commonly NCLS (normalized cumulative Lagrangian separation) performance indicator modified version, NCLSmod, which considers both movement orientation trajectories. LHM was executed three scenarios: forced only tide, tide wind combined, wind. different varied response ocean–atmosphere conditions their variations at time accident. In times calm wind, tidal influence performed better, while wind-forced better when winds greater than 7 km h−1. use FVCOM solved coastal circulation accounted for bathymetric effects area. resulted improved variability distribution modeled compared observed drifter work first related cases Chile, provides fast tool search areas based ensemble forecasts publicly available sources.

Language: Английский

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Influence of Ocean Current Features on the Performance of Machine Learning and Dynamic Tracking Methods in Predicting Marine Drifter Trajectories

Journal of Marine Science and Engineering, Journal Year: 2024, Volume and Issue: 12(11), P. 1933 - 1933

Published: Oct. 28, 2024

Accurately and rapidly predicting marine drifter trajectories under conditions of information scarcity is critical for addressing maritime emergencies conducting surveys with resource-limited unmanned vessels. Machine learning-based tracking methods, such as Long Short-Term Memory networks (LSTM), offer a promising approach trajectory prediction in scenarios. This study combines satellite observations idealized simulations to compare the predictive performance LSTM resource-dependent dynamic method (DT). The results indicate that when driven solely by historical paths, achieves better predictions trained tested on relative intervals rather than absolute positions individual points. In general, provides more accurate geometric pattern at initial stages forecasting, while DT offers superior accuracy specific positions. velocity curvature ocean currents jointly influence quality both methods. regions characterized active sub-mesoscale dynamics, fast-flowing meandering Kuroshio Current Extension, predicts reliable patterns but lacks precision detailed position estimates compared LSTM. However, areas dominated fast relatively straight North Equatorial Current, two methods reverses. also demonstrate different tolerances noise sampling intervals. establishes baseline selecting machine learning highlights limitations AI-based data-scarce resource-constrained conditions.

Language: Английский

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Modelling floating riverine litter in the south-eastern Bay of Biscay: a regional distribution from a seasonal perspective

Published: May 18, 2022

Abstract. Although rivers contribute to the flux of litter coastal and marine environment, estimates riverine amounts are scarce behaviour at river mouths waters is highly uncertain. This paper provides a comprehensive overview seasonal trends floating transport fate in south-eastern Bay Biscay based on characterization, drifters high-frequency radars observations Lagrangian simulations. Virtual particles were released close as proxy entering ocean from parameterized with wind drag coefficient (Cd) represent their trajectories according buoyancy items. They forced numerical winds measured currents provided by covering selected week-long periods between 2009 2021. To gain better insight type items, samples collected barrier placed Deba (Spain) characterized laboratory. Items grouped into two categories: low buoyant items (objects not exposed forcing e.g., plastic bags) forcing, bottles). Overall, encompassed almost 90 % number 68 weight. Low parametrized Cd=0 %, Cd=4 this later one result joint analysis modelled observed four satellite drifting buoys Adour (France), Oria mouths. Results show that all regions study area affected within or nearby region itself. Simulations showed drifted faster towards coast wind, notably during first 24 hours. In summer, over 97 beached after week simulation. autumn value fell 54 %. contrast, take longer arrive coastline, particularly Spring fewer than 25 end When comparing coastline concentrations, highest concentrations (>200 particles/km) recorded summer French Pyrénées-Atlantiques for These results coupled river-by-river modelling approach can assist policy decision makers setting emergency responses high fluxes arrivals defining future monitoring strategies heavy polluted area.

Language: Английский

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The effect of model tidal forcing on virtual particle dispersion and accumulation at the ocean surface

Published: Sept. 16, 2022

Understanding the pathways of floating material at surface ocean is important to improve our knowledge on circulation and for its ecological environmental impacts. Virtual particle simulations are a common method simulate dispersion material. To advect particles, models’ velocities usually used, but only recent ones include tidal forcing. Our research question is: What effect forcing virtual accumulation surface? As inputs we use velocity outputs from eNATL60, twin simulation with without We focus Açores Islands region find: 1) Surface particles have larger displacement, lower distance travelled than 2) seasonal differences depend spatial scale structures 3) A greater variability in present

Language: Английский

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Coastal HF radars in the Mediterranean: Applications in support of science priorities and societal needs

Published: Dec. 14, 2021

Abstract. The Mediterranean Sea is a prominent climate change hot spot, being their socio-economically vital coastal areas the most vulnerable targets for maritime safety, diverse met-ocean hazards and marine pollution. Providing an unprecedented spatial temporal resolution at wide areas, High-frequency radars (HFRs) have been steadily gaining recognition as effective land-based remote sensing technology continuous monitoring of surface circulation, increasingly waves occasionally winds. HFR measurements boosted thorough scientific knowledge processes, also fostering broad range applications, which has promoted integration in Coastal Ocean Observing Systems worldwide, with more than half European sites located areas. In this work, we present review existing data multidisciplinary science-based applications Sea, primarily focused on meeting end-users science-driven requirements, addressing regional challenges three main topics: i) safety; ii) extreme hazards; iii) environmental transport process. Additionally, observing capabilities region required to underpin underlying science further development are analyzed. outcome assessment allowed us finally provide set recommendations future improvement prospects maximize contribution extending products into societal relevant downstream services support blue growth helping meet UN’s Decade Science Sustainable Development EU’s Green Deal goals.

Language: Английский

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