Offer Description
Tallinn University of Technology School of Science, Department of Cybernetics offers a 4-year PhD position in Applied Physics and Mathematics.
The Proposed PhD thesis topic: “Local drivers of extreme water levels in the eastern Baltic Sea”
Supervisors:
- Sup. Tenured Full Professor Dr. Tarmo Soomere, Department of Cybernetics: Laboratory of Wave Engineering
- Co-Sup. Researcher Dr. Katri Viigand, Department of Cybernetics: Laboratory of Wave Engineering
Summary
Extreme water levels pose a major challenge for engineering structures and low-lying coastal areas. This PhD project examines spatio-temporal variability of wave set-up, a key contributor to storm-driven high water levels that can considerably increase flooding risks at exposed shores of the Baltic Sea. By combining wave modelling, field observations, remote sensing, advanced mathematical methods and AI, the research will quantify spatial patterns of wave set-up, its statistical distributions and co-occurrence with offshore extreme sea levels. The project aims at applying physics-based modelling and advanced analysis to mitigate an environmental challenge with direct implications for coastal risk management and climate adaptation.
The research
Extreme water levels are a key concern in nearshore management and engineering. In the semi-sheltered non-tidal Baltic Sea, they result from variations in the overall water volume of the basin, storm surges, and local processes such as wave set-up and run-up (Soomere et al., 2015). These mechanisms act on different spatial and temporal scales and follow distinct statistical distributions (Soomere et al., 2016).
Wave set-up is created by breaking waves that transfer their momentum to the water column, raising mean water levels at the shoreline (Longuet-Higgins and Stewart, 1962; Holman and Sallenger, 1985; Dean and Bender, 2006; Dean and Walton, 2010; Pugh and Woodworth, 2014). This phenomenon is usually the largest commonly ignored contribution to extreme water levels (Melet et al., 2018). In low-energy but highly intermittent wave climates (Vetter et al., 2010), such as the Baltic Sea (Su et al., 2024; Eelsalu et al., 2025), wave set-up can contribute substantially to total water levels (Eelsalu et al., 2014; Pindsoo and Soomere, 2015). Its magnitude depends on offshore wave height, approach angle, and shoreline geometry (Stockdon et al., 2006, Soomere et al., 2015). In coastal areas with complex shape, set-up varies considerably alongshore, with the highest values often observed in bayheads. In the Tallinn area, wave set-up follows either an exponential or inverse Gaussian (Wald) distribution, suggesting that severe events may be more frequent than expected from general sea statistics (Soomere et al., 2020).
In the West Estonian archipelago, wave set-up may reach 0.7–0.8 m, contributing ~30% of total extreme water level (Soomere et al., 2013; Pindsoo and Soomere, 2015; Soomere et al., 2020). Given the exposure to the dominant SW and NNW winds and wave systems (Soomere et al., 2024), wave setup likely occurs more frequently along the western coast of Estonia, Latvia and Lithuania. Importantly, the most damaging events occur when high set-up coincides with high offshore water levels.
The proposed PhD studies aim at quantification of the contribution and variability of wave set-up in the eastern Baltic Sea using computational modelling, observations, remote sensing, advanced mathematical methods for the analysis of extremes, and AI. The research will also determine the nature of statistical distribution of set-up heights and examine co-occurrence of high set-up with extreme offshore water levels.
The research questions are:
- How does wave set-up height vary spatially and temporally along the eastern Baltic Sea coast?
- What statistical distribution does wave set-up follow in semi-sheltered sea areas?
- How often do high wave set-up and extreme offshore water levels co-occur, and what are the implications for coastal flooding?
- Can wave set-up be quantified from observations or remote sensing data, and how it compares to simulations?
References
Dean, R. G., & Bender, C. J. (2006). Static wave set-up with emphasis on damping effects by vegetation and bottom friction. Coastal Engineering, 53(2), 149–165. https://doi.org/10.1016/j.coastaleng.2005.10.005
Dean, R. G., & Walton, T. L. (2010). Wave setup. In Y. C. Kim (Ed.), Handbook of Coastal and Ocean Engineering (pp. 1–23). New Jersey: World Scientific. https://doi.org/10.1142/9789812819307_0001
Eelsalu, M., Soomere, T., Pindsoo, K., & Lagemaa, P. (2014). Ensemble approach for projections of return periods of extreme water levels in Estonian waters. Continental Shelf Research, 91, 201−210. https://doi.org/10.1016/j.csr.2014.09.012.
Eelsalu, M., Soomere, T., Parnell, K. E., & Viška, M. (2025). Attribution of alterations in coastal processes in the southern and eastern Baltic Sea to climate change driven modifications of coastal drivers. Oceanologia, 67(1), 67103. https://doi.org/10.5697/LXTZ5389
Holman, R. A., & Sallenger, A. H., Jr. (1985). Setup and swash on a natural beach. Journal of Geophysical Research, 90(C1), 945–953. https://doi.org/10.1029/JC090iC01p00945
Longuet-Higgins, M. S., & Stewart, R. W. (1962). Radiation stress and mass transport in gravity waves, with applications to “surf beats.” Journal of Fluid Mechanics, 13(4), 481–504. https://doi.org/10.1017/S0022112062000877
Melet, A., Meyssignac, B., Almar, R., & Le Cozannet, G. (2018). Under-estimated wave contribution to coastal sea-level rise. Nature Climate Change, 8, 234–239. https://doi.org/10.1038/s41558-018-0088-y
Pindsoo, K., & Soomere, T. (2015). Contribution of wave set-up into the total water level in the Tallinn area. Proceedings of the Estonian Academy of Sciences, 64, 338–348. https://doi.org/10.3176/proc.2015.3S.03
Pugh, D. T., & Woodworth, P. L. (2014). Sea-Level Science: Understanding Tides, Surges, Tsunamis, and Mean Sea-Level Changes. Cambridge: Cambridge University Press. ISBN 9781107028197.
Soomere, T., & Pindsoo, K. (2016). Spatial variability in the trends in extreme storm surges and weekly-scale high water levels in the eastern Baltic Sea. Continental Shelf Research, 115, 53–64. https://doi.org/10.1016/j.csr.2015.12.016
Soomere, T., Eelsalu, M., Kurkin, A., & Rybin, A. (2015). Separation of the Baltic Sea water level into daily and multi-weekly components. Continental Shelf Research, 103, 23−32. https://doi.org/10.1016/j.csr.2015.04.018
Soomere, T., Eelsalu, M., Viigand, K., & Giudici, A. (2024). Linking changes in the directional distribution of moderate and strong winds with changes in wave properties in the eastern Baltic proper. Journal of Coastal Research, Special Issue 113, 190–194. https://doi.org/10.2112/JCR-SI113-038.1
Soomere, T., Pindsoo, K., Bishop, S. R., Käärd, A., & Valdmann, A. (2013). Mapping wave set-up near a complex geometric urban coastline. Natural Hazards and Earth System Sciences, 13(11), 3049–3061. https://doi.org/10.5194/nhess-13-3049-2013
Stockdon, H. F., Holman, R. A., Howd, P. A., & Sallenger, A. H., Jr. (2006). Empirical parameterization of setup, swash, and runup. Coastal Engineering, 53(7), 573–588. https://doi.org/10.1016/j.coastaleng.2005.12.005
Su, J., Murawski, J., Nielsen, J.W., & Madsen, K.S., 2024. Coinciding storm surge and wave setup: A regional assessment of sea level rise impact. Ocean Engineering, 305, 117885. https://doi.org/10.1016/j.oceaneng.2024.117885
Vetter, O., Becker, J. M., Merrifield, M. A., Pequignet, A-C., Aucan, J., Boc, S. J., Pollock, C. E. (2010). Wave setup over a Pacific Island fringing reef. Journal of Geophysical Research, 115(C12066). https://doi.org/10.1029/2010JC006455
Responsibilities and (foreseen) tasks
- Perform simulations of wave set-up in the eastern Baltic Sea 1961–2025
- Map areas with frequently occurring large wave set-up heights
- Identify common statistical distributions of set-up heights along the study area
- Establish links between large offshore sea level and high set-up events
- Explore options of retrieving proxies of set-up height from satellite observations
- Identify decadal changes and long-term trends in set-up heights
- Provide input to other research projects in the lab
- Contribute to the organization of research and workshops where the findings are presented
Where to apply
E-mail: tarmo.soomere@taltech.ee
Skills/Qualifications
Applicants should fulfil the following requirements:
- a master’s degree or equivalent qualification in physical, mathematical, engineering or Earth sciences, (preferably physical oceanography, civil, coastal or ocean engineering, with strong background in mathematics and statistics)
- a clear interest in the topic of the position
- excellent command of English
- strong and demonstrable writing and analytical skills
- capacity to work both as an independent researcher and as part of an international team
- capacity and willingness to provide assistance in organizational tasks in the lab
The following experience is beneficial
- experience with common scientific software (e.g., Matlab, Mathematica, Python, R)
- working knowledge of statistics
- supervision of BSc students
- popularisation of science
Specific Requirements
Application procedure
The information for the PhD admission is available at TalTech´s web-page: https://taltech.ee/en/phd-admission
The following application documents should be sent to tarmo.soomere@taltech.ee
- CV
- Motivation letter
- Degree certificates as required by the university
- Copy of the passport
Additional Information
Benefits
We offer:
- 4-year PhD position in one of the most internationalised and advanced marine and coastal research teams in the Baltic States, with extensive portfolio of pan-European and national research endeavours.
- Supervision by internationally recognised experts in the field.
- The chance to do high-level research that is immediately implemented in practice for design of coastal engineering structures and for sustainable coastal management.
- Extensive opportunities for specialised conference visits, research stays and networking with leading universities and research centres in coastal and ocean engineering.
- Hands-on training in science popularization and communication and science diplomacy.
Additional comments
About the laboratory
The Wave Engineering Laboratory, originally a part of the Center of Excellence for Nonlinear Studies, is now one of the core labs of the Department of Cybernetics, School of Science of Tallinn University of Technology. The team focuses on complex and nonlinear phenomena in wave dynamics and coastal engineering, and the applications of mathematical methods in wave studies, with overall aim to transfer advancements in fundamental research into solutions for everyday use by practitioners and support science-based decision-making in coastal matters.
The scope of research involves, but is not limited to:
- long wave theory and applications, with emphasise on fast-ferry waves, shallow-water solitons, set-up and run-up phenomena, tsunami research, and generic aspects of coastal hazards,
- surface wave modelling, wave climate studies, and wave-driven phenomena in coastal engineering, with application to engineering design and integrated coastal zone management.
Rapidly emerging new foci are:
- the use of Lagrangian transport of different substances in marine environment for marine and maritime spatial planning,
- adequate description of hydrodynamic (wave and water level) extremes,
- preventive methods for mitigation of marine-induced hazards,
- application of machine learning techniques and opportunities provided by AI.
Even though the listed advanced topics are mostly at the cutting edge of fundamental research in the field, the team has managed to successfully explain the results to wider society and to convert research outcome into practical technologies and applications.
For further information, please contact Prof Dr Tarmo Soomere tarmo.soomere@taltech.ee and/or Dr Katri Viigand katri.viigand@taltech.ee or visit https://wavelab.taltech.ee
