The research, published in the journal Natural Hazards, was carried out by Fernando Oreiro of Argentina’s Servicio de Hidrografía Naval and the University of Buenos Aires, Iael Perez of the Finnish Environment Institute, and Walter Dragani of CONICET and several Argentine research institutions. The team took advantage of a rare observational asset: simultaneous sea-level records collected between January and April 2018 at paired offshore and inner-harbor stations associated with three very different ports along the southwestern Atlantic coast. Those ports were Montevideo, the Uruguayan capital sitting on the Río de la Plata; Mar del Plata, a busy fishing and tourist harbor on the open Argentine coast; and Quequén, a deepwater grain port farther south, whose estuary entrance is famous among coastal scientists for its violent short-period oscillations.

The raw tide-gauge data, like all sea-level records, contains a mixture of signals: slow tides, storm surges that build over hours or days, and the rapid oscillations that interest meteotsunami researchers. To isolate the latter, the authors applied a high-pass filter to each record, stripping away the long-period background and leaving the oscillations with periods shorter than roughly a few hours. What emerged was a striking pattern in time. Episodes of energetic long-wave activity did not appear at one port in isolation; they arrived in sequence, first at Quequén, then at Mar del Plata, and finally at Montevideo. This northward progression matched the northeastward track of cold fronts sweeping across the region, pointing to atmospheric gravity waves trailing those fronts as the likely trigger for the ocean oscillations.

To go beyond visual inspection of the filtered records, the team turned to spectral analysis, a mathematical technique that decomposes a wobbly time series into the amplitudes of the individual frequencies that make it up. Comparing the spectrum measured offshore with the spectrum measured inside each harbor reveals how the local basin transforms incoming wave energy. If a harbor acts as a resonator, it amplifies particular frequencies, just as a wine glass rings at a specific pitch when struck. The classic theory of harbor oscillation, developed in the early 1960s by researchers such as John Miles and Walter Munk, predicts that each basin has a set of natural, or eigen, periods determined by its size, depth, and geometry. The new study put that theory to a natural test across three basins of very different shape.

The results were anything but uniform. Montevideo Bay displayed the strongest amplification of the three sites, with a persistent enhancement of sea-level energy concentrated at relatively low frequencies. In other words, when long waves associated with frontal passages swept into the Río de la Plata, the broad bay rang like a resonating chamber, steadily boosting energy at the low end of the spectrum. Mar del Plata Harbor behaved differently: its amplification was weaker and spread across a broader, more irregular band of frequencies, suggesting a more complicated resonant structure with multiple modes of varying strength rather than a single dominant one. Quequén Harbor, despite its reputation for dramatic oscillations, showed comparatively weak spectral enhancement inside the port relative to the offshore signal, maintaining a much closer correspondence with the long-wave field arriving from the shelf.

Because spectra averaged over the whole four-month record can hide how the relationship between offshore and harbor signals evolves through individual events, the researchers also applied wavelet coherence analysis, a technique that measures how tightly two time series are linked at each frequency and at each moment in time. The method, popularized for geophysical data in a widely cited 2004 paper by Grinsted and colleagues, allowed the team to see when harbor and offshore oscillations were locked in step and when they drifted apart. At Quequén, the coherence between the offshore long-wave field and the harbor response was persistent and strong, reinforcing the picture of a port that largely transmits and modestly reshapes the incoming wave energy. At Mar del Plata, coherent coupling was present but less continuous. Montevideo showed the weakest and most intermittent coherence, implying that the bay’s response is governed more by its own internal resonance than by a direct, moment-to-moment coupling with the offshore signal.

These findings carry a subtle but important message for how coastal scientists think about harbor hazards. It is tempting to assume that a port’s vulnerability to meteotsunamis can be predicted from its theoretical oscillation periods alone: compute the natural modes of the basin, compare them with the frequencies contained in the incoming atmospheric disturbance, and flag any overlap. The comparative data from the southwestern Atlantic complicates that picture. The authors conclude that harbor amplification depends not only on basin geometry and theoretical resonant periods, but also on the trajectory and incidence angle of the incoming disturbance. A wave train arriving along one bearing may couple efficiently into a harbor’s modes, while the same basin may barely respond to an energetically equivalent disturbance approaching from a different direction. Numerical work by other groups, including studies of harbor oscillation induced by pressure disturbances moving in different directions along the Yellow Sea coast, has pointed to the same conclusion, but few observational studies have documented it across multiple real ports at once.

The regional context amplifies the significance of the work. The Buenos Aires continental shelf is exceptionally wide and shallow, and previous research, including a 2022 case study by Dragani and colleagues and a 2024 review of global meteotsunami hazards published in Reviews of Geophysics, has established that atmospheric disturbances crossing this shelf frequently generate long ocean waves through a resonant mechanism known as Proudman resonance, in which a fast-moving pressure disturbance drags a growing ocean wave beneath it. When these waves encounter the coast, they can excite seiches, the standing oscillations of bays and harbors, with catastrophic local consequences. The 2022 event was particularly remarkable, occurring simultaneously along the Argentine and Uruguayan coasts and coinciding with the arrival of the Tonga volcanic tsunami, an overlap documented in a 2025 study by the same research group. Understanding which harbors transform such wave energy into dangerous currents is therefore a matter of practical port safety as well as fundamental science.

For port authorities, the comparative framework offers a concrete lesson: two harbors facing the same open ocean can be exposed to very different risks from the same storm system. Montevideo’s persistent low-frequency amplification means that slow, large-volume oscillations are its signature hazard, with implications for mooring design and berthing operations during frontal passages. Mar del Plata’s irregular, broad-band response suggests that many different atmospheric disturbance types can find some resonant frequency to excite there. Quequén’s relatively faithful reproduction of the offshore signal implies that its risk profile is tied directly to the strength of the shelf wave field itself. The work, which was supported by Argentina’s National Scientific and Technical Research Council, also demonstrates the value of simply measuring the same events at paired offshore and harbor stations, an approach the authors suggest can sharpen meteotsunami hazard assessments well beyond the classical eigenperiod calculation. As climate-driven changes in atmospheric circulation continue to alter the frequency and character of frontal systems worldwide, knowing not just where meteotsunamis form but how each harbor listens to them may prove essential for the ports of the southwestern Atlantic and beyond.

Subject of Research: Frequency-dependent harbor response to meteotsunamis along the Argentine and Uruguayan coasts

Article Title: Comparative frequency-dependent harbor response to meteotsunamis along the Argentine and Uruguayan coasts

Article References: Oreiro, F., Perez, I., & Dragani, W. (2026). Comparative frequency-dependent harbor response to meteotsunamis along the Argentine and Uruguayan coasts. Natural Hazards, 122(20), Article 648. https://doi.org/10.1007/s11069-026-08408-y

Image Credits: AI Generated

DOI: 10.1007/s11069-026-08408-y

Keywords: meteotsunami, harbor resonance, sea level oscillations, atmospheric gravity waves, spectral analysis, wavelet coherence, Argentina, Uruguay, Natural Hazards, coastal hazards, seiches, southwestern Atlantic

The research, led by Alejandro González and Jorge Macías of the University of Málaga together with Cléa Denamiel of the Ruđer Bošković Institute in Croatia, evaluates the performance of the Meteo-HySEA model against the state-of-the-art AdriSC-ADCIRC modeling suite. Meteo-HySEA, developed by the EDANYA research group in Málaga, belongs to the HySEA family of codes, which also includes the widely used Tsunami-HySEA and Landslide-HySEA models recognized as European flagship tools for simulating seismically and landslide-triggered tsunamis. What sets Meteo-HySEA apart is its combination of high-resolution finite volume numerical schemes with a native multi-GPU framework, allowing it to incorporate time-dependent atmospheric pressure fields as forcing while running orders of magnitude faster than conventional CPU-based models. Crucially, it can also simulate the onshore inundation that follows, extending the modeling chain from offshore wave generation all the way to flooded harbor quays.

The benchmark for the new model was the AdriSC system, a CPU-based coupled atmosphere-ocean modeling framework that has become the reference tool for meteotsunami research in the Adriatic. AdriSC couples the Weather Research and Forecasting model, downscaled to 1.5-kilometer resolution over the Adriatic, with the two-dimensional depth-integrated ADCIRC ocean model running on an unstructured mesh refined to spatial resolutions of up to 10 meters in vulnerable zones. This minute-scale atmospheric forcing is essential to capture the speed and amplitude of tsunamigenic pressure disturbances that excite Proudman resonance across the basin and the fundamental oscillation modes of the bays, which typically fall in the 10-to-40-minute period band. However, the computational cost of such CPU-based frameworks creates serious bottlenecks for ensemble forecasting, probabilistic hazard assessment, and real-time early warning, where reducing simulation times from hours to minutes is essential.

The team focused on three well-documented events that struck the meteotsunami-prone harbors of Vela Luka on Korčula Island and Stari Grad and Vrboska on Hvar Island. The first, on 25–26 June 2014, was triggered by a train of atmospheric gravity waves propagating from the Tyrrhenian Sea across the Adriatic, producing rapid pressure perturbations of up to 2.4 hectopascals in five minutes and maximum sea levels reaching 1.5 meters inside the harbors. The second, from late June to early July 2017, was associated with a synoptic cyclone over the central Mediterranean and upper-level jet stream winds exceeding 55 meters per second; oscillations lasted nearly 24 hours, with amplitudes up to 0.69 meters at tide gauges and exceeding one meter as captured in videos from Vrboska. The third, a remarkable multi-day sequence between 11 and 19 May 2020, produced repeated waves of 0.6 to 0.8 meters driven by recurring high-frequency pressure disturbances of 2 to 4 hectopascals, flooding harbors and leaving boats ashore on multiple days.

A distinctive feature of the study is its deliberately strict evaluation protocol. No correction or tuning of the atmospheric forcing was applied, ensuring that both modeling systems were tested under realistic operational conditions rather than with the benefit of hindsight. This choice matters because retrospective adjustments of pressure fields could improve agreement with observations, but such approaches rely on prior knowledge of the event and are therefore useless in a real-time forecasting context. The evaluation drew on high-frequency observations from the MESSI observational network, which includes microbarographs measuring atmospheric pressure at one-minute intervals with a precision of plus or minus 0.01 hectopascals and radar tide gauges recording sea level with millimeter accuracy, supplemented for the earlier events by five-minute pressure records from the Crometeo network of amateur weather stations across the Croatian coast.

The results reveal a fundamental constraint that applies to any meteotsunami modeling system: simulation accuracy is ultimately limited by the quality of the atmospheric forcing. Comparing weather model simulations driven by the ERA-Interim and ERA5 reanalyses, the researchers found that the ERA-Interim forcing systematically generated more intense and widespread pressure anomalies, sometimes exceeding observed amplitudes and producing spurious fluctuations, while ERA5-driven simulations yielded more localized and lower-amplitude disturbances that aligned better with observations in timing and structure but often missed the strongest pressure jumps. Most strikingly, the ERA5-driven simulation completely failed to reproduce the sharp 2.5-hectopascal pressure jump recorded on 11 May 2020, the most intense disturbance of the entire study period. Because observational coverage over the central Adriatic remains sparse, the authors note, fully assessing the skill of atmospheric models in this region is itself a difficult task.

Against this backdrop, Meteo-HySEA performed encouragingly. The model successfully reproduced the timing and spatial variability of sea-level oscillations across all three events and generally yielded higher amplitudes than AdriSC-ADCIRC under the same forcing. During the June 2014 event, for example, Meteo-HySEA produced peak amplitudes of roughly one meter in Vela Luka compared with 0.6 meters from AdriSC-ADCIRC, suggesting it may better capture the potential extremes of meteotsunami events. However, a systematic shortcoming also emerged: Meteo-HySEA consistently overestimated the dominant wave periods, particularly in semi-enclosed basins. In Stari Grad, its median simulated wave periods exceeded observed values by up to 50 percent. The authors attribute this to the wet-dry technique used to simulate inundation, which causes the effective geomorphology of harbors to evolve over time, and to limited coastal bathymetric coverage. Both models, it should be noted, also overestimated observed periods, indicating that harbor resonance characteristics remain difficult to represent accurately in general.

To probe the differences between the two systems more deeply, the team ran controlled numerical experiments with synthetic pressure disturbances based on the analytical formulation developed for the AdriSC meteotsunami surrogate model. These idealized disturbances, defined by parameters such as origin, propagation direction, amplitude, translation speed, period, and spatial width, were chosen to produce the strongest plausible meteotsunamis in each harbor. The comparison exposed systematic differences in how the two models trap and dissipate energy within semi-enclosed basins. In Vela Luka, Meteo-HySEA predicted extreme elevations exceeding five meters under the most severe synthetic forcing, compared with peaks closer to four meters for AdriSC-ADCIRC, along with a slower decay of oscillations. The analysis also uncovered a genuine physical phenomenon: a massive, localized meteotsunami setup of up to 1.8 meters at the tip of Vela Luka harbor, generated by resonant mass transport, on which the high-frequency seiches ride. Both components, the authors stress, must be retained together to assess total coastal flooding hazard.

The study also candidly documents technical limitations. Spurious hotspots appeared in maximum sea-level maps for Stari Grad and Vrboska, driven by sparse raw bathymetric data near coastlines and numerical artifacts of projecting complex coastal boundaries onto high-resolution structured grids, where abrupt bathymetric steps cause the flow to behave as if hitting a vertical wall. In Vrboska, the narrow channel characteristics could not be resolved even at seven-meter grid spacing, shifting the modeled coastline relative to satellite imagery. The authors emphasize that numerical interpolation cannot artificially reconstruct missing physical topography, making high-quality, high-resolution topobathymetric surveys a critical requirement for nearshore areas if the inundation capabilities of the new model are to be fully exploited.

Nevertheless, the overall verdict is that GPU-based solvers like Meteo-HySEA represent a promising pathway toward next-generation meteotsunami forecasting and hazard assessment. Because the model runs orders of magnitude faster than CPU-based alternatives, it opens the door to real-time operational use, ensemble forecasting, and explicit treatment of atmospheric and boundary-condition uncertainties, all of which are essential given that the lead time between disturbance detection and coastal impact in the Adriatic is typically less than three hours. The authors outline future work on three fronts: implementing wind stress, tidal, and general circulation forcing in the next release of the code; systematic validation with dense observational networks to determine whether the longer persistence of oscillations in Meteo-HySEA reflects more realistic harbor seiches or whether ADCIRC’s stronger damping better represents physical energy dissipation; and testing the model’s operational potential through integration with real-time atmospheric forecasts and early warning protocols in collaboration with civil protection agencies. With atmospheric forcing remaining the dominant source of forecast uncertainty, advances in convection-permitting ensembles and machine-learning-based nowcasting are expected to further improve fidelity, strengthening coastal resilience in the Adriatic and potentially at meteotsunami hotspots worldwide.

Subject of Research: Evaluation of the GPU-based Meteo-HySEA model for simulating atmospherically driven meteotsunami events and harbor flooding in the Adriatic Sea

Article Title: Assessing Meteo-HySEA performance for Adriatic meteotsunami events

Article References: Assessing Meteo-HySEA performance for Adriatic meteotsunami events. (n.d.). https://doi.org/10.1007/s11069-026-08351-y

Image Credits: AI Generated

DOI: 10.1007/s11069-026-08351-y

Keywords: meteotsunami, Adriatic Sea, Meteo-HySEA, GPU modeling, harbor resonance, Proudman resonance, coastal flooding, early warning systems, atmospheric pressure disturbances, AdriSC-ADCIRC, sea-level oscillations, numerical simulation