Articles | Volume 30, issue 4
https://doi.org/10.5194/npg-30-515-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/npg-30-515-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
21 Nov 2023
Research article |
| 21 Nov 2023
| 21 Nov 2023
Superstatistical analysis of sea surface currents in the Gulf of Trieste, measured by high-frequency radar, and its relation to wind regimes using the maximum-entropy principle
Sofia Flora
CORRESPONDING AUTHOR
Dipartimento di Matematica e Geoscienze, University of Trieste, Trieste, Italy
National Institute of Oceanography and Applied Geophysics – OGS, Oceanographic Section, Trieste, Italy
Laura Ursella
National Institute of Oceanography and Applied Geophysics – OGS, Oceanographic Section, Trieste, Italy
Achim Wirth
Univ. Grenoble Alpes, CNRS, Grenoble INP, LEGI, 38000 Grenoble, France
Related authors
Davide Lombardo, Sofia Flora, Fabio Giordano, Emanuele Ingrassia, Milena Menna, Stefano Querin, and Laura Ursella
Ocean Sci., 21, 2197–2214, https://doi.org/10.5194/os-21-2197-2025, https://doi.org/10.5194/os-21-2197-2025, 2025
Short summary
Short summary
This study analyses the extreme meteo-marine event of October–November 2023 in the Gulf of Trieste, characterised by southerly strong winds, heavy rainfall, and high river discharge. Using high-frequency radar data, wind records, and numerical models, we analysed the interactions between river discharge and wind-driven currents. Results show that strong river discharge can dominate coastal circulation and overlay the wind effects. This multi-platform approach provides valuable insights into ocean dynamics.
Sofia Flora, Laura Ursella, and Achim Wirth
Geosci. Model Dev., 18, 4685–4712, https://doi.org/10.5194/gmd-18-4685-2025, https://doi.org/10.5194/gmd-18-4685-2025, 2025
Short summary
Short summary
We developed a hierarchy of idealized deterministic–stochastic models to simulate sea surface currents in the Gulf of Trieste. They include tide- and wind-driven sea surface current components, resolving the slowly varying part of the flow, and a stochastic signal, representing the fast-varying small-scale dynamics. The comparison with high-frequency radar observations shows that the non-Gaussian stochastic model captures key dynamics and mimics the observed fat-tailed probability distribution.
Davide Lombardo, Sofia Flora, Fabio Giordano, Emanuele Ingrassia, Milena Menna, Stefano Querin, and Laura Ursella
Ocean Sci., 21, 2197–2214, https://doi.org/10.5194/os-21-2197-2025, https://doi.org/10.5194/os-21-2197-2025, 2025
Short summary
Short summary
This study analyses the extreme meteo-marine event of October–November 2023 in the Gulf of Trieste, characterised by southerly strong winds, heavy rainfall, and high river discharge. Using high-frequency radar data, wind records, and numerical models, we analysed the interactions between river discharge and wind-driven currents. Results show that strong river discharge can dominate coastal circulation and overlay the wind effects. This multi-platform approach provides valuable insights into ocean dynamics.
Sofia Flora, Laura Ursella, and Achim Wirth
Geosci. Model Dev., 18, 4685–4712, https://doi.org/10.5194/gmd-18-4685-2025, https://doi.org/10.5194/gmd-18-4685-2025, 2025
Short summary
Short summary
We developed a hierarchy of idealized deterministic–stochastic models to simulate sea surface currents in the Gulf of Trieste. They include tide- and wind-driven sea surface current components, resolving the slowly varying part of the flow, and a stochastic signal, representing the fast-varying small-scale dynamics. The comparison with high-frequency radar observations shows that the non-Gaussian stochastic model captures key dynamics and mimics the observed fat-tailed probability distribution.
Achim Wirth
Nonlin. Processes Geophys., 32, 261–280, https://doi.org/10.5194/npg-32-261-2025, https://doi.org/10.5194/npg-32-261-2025, 2025
Short summary
Short summary
The hydrostatic approximation is the basis of most simulations of ocean and climate dynamics. It is evaluated here by using a projection method in the 4D Fourier space. The evaluation is analytic.
Felipe L. L. Amorim, Julien Le Meur, Achim Wirth, and Vanessa Cardin
Ocean Sci., 20, 463–474, https://doi.org/10.5194/os-20-463-2024, https://doi.org/10.5194/os-20-463-2024, 2024
Short summary
Short summary
Analysis of a high-frequency time series of thermohaline data measured at the EMSO-E2M3A regional facility in the southern Adriatic Pit (SAP) reveals a significant change in the double-diffusive regime in 2017 associated with the intrusion of extremely salty waters into the area, suggesting salt fingering as the dominant regime. The strong heat loss at the surface during this winter allowed deep convection to transport this high-salinity water from the intermediate to deep layers of the pit.
Nydia Catalina Reyes Suárez, Valentina Tirelli, Laura Ursella, Matjaž Ličer, Massimo Celio, and Vanessa Cardin
Ocean Sci., 18, 1321–1337, https://doi.org/10.5194/os-18-1321-2022, https://doi.org/10.5194/os-18-1321-2022, 2022
Short summary
Short summary
Explaining the dynamics of jellyfish blooms is a challenge for scientists. Biological and meteo-oceanographic data were combined on different timescales to explain the exceptional bloom of the jellyfish Rhizostoma pulmo in the Gulf of Trieste (Adriatic Sea) in April 2021. The bloom was associated with anomalously warm seasonal sea conditions. Then, a strong bora wind event enhanced upwelling and mixing of the water column, causing jellyfish to rise to the surface and accumulate along the coast.
Pablo Lorente, Eva Aguiar, Michele Bendoni, Maristella Berta, Carlo Brandini, Alejandro Cáceres-Euse, Fulvio Capodici, Daniela Cianelli, Giuseppe Ciraolo, Lorenzo Corgnati, Vlado Dadić, Bartolomeo Doronzo, Aldo Drago, Dylan Dumas, Pierpaolo Falco, Maria Fattorini, Adam Gauci, Roberto Gómez, Annalisa Griffa, Charles-Antoine Guérin, Ismael Hernández-Carrasco, Jaime Hernández-Lasheras, Matjaž Ličer, Marcello G. Magaldi, Carlo Mantovani, Hrvoje Mihanović, Anne Molcard, Baptiste Mourre, Alejandro Orfila, Adèle Révelard, Emma Reyes, Jorge Sánchez, Simona Saviano, Roberta Sciascia, Stefano Taddei, Joaquín Tintoré, Yaron Toledo, Laura Ursella, Marco Uttieri, Ivica Vilibić, Enrico Zambianchi, and Vanessa Cardin
Ocean Sci., 18, 761–795, https://doi.org/10.5194/os-18-761-2022, https://doi.org/10.5194/os-18-761-2022, 2022
Short summary
Short summary
High-frequency radar (HFR) is a land-based remote sensing technology that can provide maps of the surface circulation over broad coastal areas, along with wave and wind information. The main goal of this work is to showcase the current status of the Mediterranean HFR network as well as present and future applications of this sensor for societal benefit such as search and rescue operations, safe vessel navigation, tracking of marine pollutants, and the monitoring of extreme events.
Achim Wirth and Bertrand Chapron
Nonlin. Processes Geophys., 28, 371–378, https://doi.org/10.5194/npg-28-371-2021, https://doi.org/10.5194/npg-28-371-2021, 2021
Short summary
Short summary
In non-equilibrium statistical mechanics, which describes forced-dissipative systems such as air–sea interaction, there is no universal probability density function (pdf). Some such systems have recently been demonstrated to exhibit a symmetry called a fluctuation theorem (FT), which strongly constrains the shape of the pdf. Using satellite data, the mechanical power input to the ocean by air–sea interaction following or not a FT is questioned. A FT is found to apply over specific ocean regions.
Miroslav Gačić, Laura Ursella, Vedrana Kovačević, Milena Menna, Vlado Malačič, Manuel Bensi, Maria-Eletta Negretti, Vanessa Cardin, Mirko Orlić, Joël Sommeria, Ricardo Viana Barreto, Samuel Viboud, Thomas Valran, Boris Petelin, Giuseppe Siena, and Angelo Rubino
Ocean Sci., 17, 975–996, https://doi.org/10.5194/os-17-975-2021, https://doi.org/10.5194/os-17-975-2021, 2021
Short summary
Short summary
Experiments in rotating tanks can simulate the Earth system and help to represent the real ocean, where rotation plays an important role. We wanted to show the minor importance of the wind in driving the flow in the Ionian Sea. We did this by observing changes in the water current in a rotating tank affected only by the pumping of dense water into the system. The flow variations were similar to those in the real sea, confirming the scarce importance of the wind for the flow in the Ionian Sea.
Achim Wirth and Florian Lemarié
Earth Syst. Dynam., 12, 689–708, https://doi.org/10.5194/esd-12-689-2021, https://doi.org/10.5194/esd-12-689-2021, 2021
Short summary
Short summary
We show that modern concepts of non-equilibrium statistical mechanics can be applied to large-scale environmental fluid dynamics, where fluctuations are not thermal but come from turbulence. The work theorems developed by Jarzynski and Crooks are applied to air–sea interaction. Rather than looking at the average values of thermodynamic variables, their probability density functions are considered, which allows us to replace the inequalities of equilibrium statistical mechanics with equalities.
Cited articles
Bogunović, B. and Malačič, V.: Circulation in the Gulf of Trieste: Measurements and model results, Nuovo Cimento C, 31, 301–326, 2008. a
CRMA – Centro Regionale di Modellistica Ambientale: Progetto NAUSICA – Downscaling di analisi meteorologiche ad alta risoluzione sul dominio Alpe Adria, https://www.arpa.fvg.it, last access: 29 March 2023. a
Corgnati, L., Mantovani, C., Novellino, A., Rubio, A., and Mader, J.: Recommendation Report 2 on improved common procedures for HFR QC analysis, JERICO-NEXT WP5-Data Management, Deliverable 5.14, Version 1.0., FREMER, https://doi.org/10.25607/OBP-944, 2018. a
Costa, M. O., Silva, R., and Anselmo, D. H. A. L.: Superstatistical and DNA sequence coding of the human genome, Phys. Rev. E, 106, 064407, https://doi.org/10.1103/PhysRevE.106.064407, 2022. a
Crombie, D. D.: Doppler spectrum of sea echo at 13.56 Mc./s., Nature, 175, 681–682, 1955. a
dos Santos, M., Menon, L., and Cius, D.: Superstatistical approach of the anomalous exponent for scaled Brownian motion, Chaos Soliton. Fract., 164, 112740, https://doi.org/10.1016/j.chaos.2022.112740, 2022. a
Ghil, M., Yiou, P., Hallegatte, S., Malamud, B. D., Naveau, P., Soloviev, A., Friederichs, P., Keilis-Borok, V., Kondrashov, D., Kossobokov, V., Mestre, O., Nicolis, C., Rust, H. W., Shebalin, P., Vrac, M., Witt, A., and Zaliapin, I.: Extreme events: dynamics, statistics and prediction, Nonlin. Processes Geophys., 18, 295–350, https://doi.org/10.5194/npg-18-295-2011, 2011. a, b
Goglio, A. C.: Progetto NAUSICA – Downscaling di analisi meteorologiche ad alta risoluzione sul dominio Alpe Adria, ARPA FVG, https://www.arpa.fvg.it/export/sites/default/tema/crma/pubblicazioni/docs_pubblicazioni/2018gen01_arpafvg_crma_nausica_rap2018_001.pdf (last access: 29 March 2023), 2018. a
Jeffries, M. A. and Lee, C. M.: A climatology of the northern Adriatic Sea's response to bora and river forcing, J. Geophys. Res.-Oceans, 112, C03S02, https://doi.org/10.1029/2006JC003664, 2007. a, b
Lorente, P., Aguiar, E., Bendoni, M., Berta, M., Brandini, C., Cáceres-Euse, A., Capodici, F., Cianelli, D., Ciraolo, G., Corgnati, L., Dadić, V., Doronzo, B., Drago, A., Dumas, D., Falco, P., Fattorini, M., Gauci, A., Gómez, R., Griffa, A., Guérin, C.-A., Hernández-Carrasco, I., Hernández-Lasheras, J., Ličer, M., Magaldi, M. G., Mantovani, C., Mihanović, H., Molcard, A., Mourre, B., Orfila, A., Révelard, A., Reyes, E., Sánchez, J., Saviano, S., Sciascia, R., Taddei, S., Tintoré, J., Toledo, Y., Ursella, L., Uttieri, M., Vilibić, I., Zambianchi, E., and Cardin, V.: Coastal high-frequency radars in the Mediterranean – Part 1: Status of operations and a framework for future development, Ocean Sci., 18, 761–795, https://doi.org/10.5194/os-18-761-2022, 2022. a
Malačič, V., Petelin, B., Gačić, M., Artegiani, A., and Orlić, M.: Regional Studies, Springer Netherlands, Dordrecht, https://doi.org/10.1007/978-94-015-9819-4_6, pp. 167–216, 2001. a, b
Okorie, U. S., Ikot, A. N., Okon, I. B., Obagboye, L. F., Horchani, R., Abdullah, H. Y., Qadir, K. W., and Abdel-Aty, A.-H.: Exact solutions of κ-dependent Schrödinger equation with quantum pseudo-harmonic oscillator and its applications for the thermodynamic properties in normal and superstatistics, Sci. Rep.-UK, 13, 2108, https://doi.org/10.1038/s41598-023-28973-7, 2023. a
Poulain, P.-M. and Raicich, F.: Forcings, Springer Netherlands, Dordrecht, https://doi.org/10.1007/978-94-015-9819-4_2, pp. 45–65, 2001. a, b, c, d
Pullen, J., Doyle, J. D., Haack, T., Dorman, C., Signell, R. P., and Lee, C. M.: Bora event variability and the role of air-sea feedback, J. Geophys. Res.-Oceans, 112, C03S18 https://doi.org/10.1029/2006JC003726, 2007. a, b
Querin, S., Crise, A., Deponte, D., and Solidoro, C.: Numerical study of the role of wind forcing and freshwater buoyancy input on the circulation in a shallow embayment (Gulf of Trieste, Northern Adriatic Sea), J. Geophys. Res.-Oceans, 111, C03S16, https://doi.org/10.1029/2006JC003611, 2006. a, b, c, d
Querin, S., Cosoli, S., Gerin, R., Laurent, C., Malačič, V., Pristov, N., and Poulain, P.-M.: Multi-platform, high-resolution study of a complex coastal system: The TOSCA experiment in the Gulf of Trieste, J. Mar. Sci. Eng. 9, 5, https://doi.org/10.3390/jmse9050469, 2021. a, b, c, d
Rizzo, S., Rapisarda, A., and Group, C.: Environmental atmospheric turbulence at Florence airport, in: AIP Conference Proceedings, vol. 742, 176–181, American Institute of Physics, https://doi.org/10.1063/1.1846475, 2004. a, b
Schäfer, B., Heppell, C. M., Rhys, H., and Beck, C.: Fluctuations of water quality time series in rivers follow superstatistics, Iscience, 24, 102881, https://doi.org/10.1016/j.isci.2021.102881, 2021. a, b, c
Ursella, L., Čermelj, B., Ličer, M., and Martini, S.: HFR-NAdr (High Frequency Radar NAdr network), European HFRadar Node [data set], https://doi.org/10.57762/8RRE-0Z07, 2023. a
Weber, J., Reyers, M., Beck, C., Timme, M., Pinto, J. G., Witthaut, D., and Schäfer, B.: Wind power persistence characterized by superstatistics, Sci. Rep.-UK, 9, 1–15, 2019. a
Short summary
An increasing amount of data allows us to move from low-order moments of fluctuating observations to their PDFs. We found the analytical fat-tailed PDF form (a combination of Gaussian and two-exponential convolutions) for 2 years of sea surface current increments in the Gulf of Trieste, using superstatistics and the maximum-entropy principle twice: on short and longer timescales. The data from different wind regimes follow the same analytical PDF, pointing towards a universal behaviour.
An increasing amount of data allows us to move from low-order moments of fluctuating...
