Wave buoys are a popular choice for measuring sea surface waves, and there is also an increasing interest for wave information from ice-covered water bodies. Such measurements require cost-effective, easily deployable, and robust devices. We have developed LainePoiss (LP)—an ice-resistant and lightweight wave buoy. It calculates the surface elevation by double integrating the data from the inertial sensors of the micro-electromechanical system (MEMS), and transmits wave parameters and spectra in real-time over cellular or satellite networks. LP was validated through: 1) sensor tests, 2) wave tank experiments, 3) a field validation against a Directional Waverider, 4) an inter-comparison of several buoys in the field, and 5) field measurements in the Baltic Sea marginal ice zone. These extensive field and laboratory tests confirmed that LP performed well (e.g., the bias of H_m0 in the field was 0.01 m, correlation 0.99 and scatter index of 8 %; the mean absolute deviation of mean wave direction was 7°). LP was also deployed with an Unmanned Aerial Vehicle and we present our experience of such operations. One issue that requires further development is the presence of low-frequency artefacts caused by the dynamic noise of the gyroscope. For now, a correction method is presented to deal with the noise. Wave buoys are a popular choice for measuring sea surface waves, and there is also an increasing interest for wave information from ice-covered water bodies. Such measurements require cost-effective, easily deployable, and robust devices. We have developed LainePoiss (LP)—an ice-resistant and lightweight wave buoy. It calculates the surface elevation by double integrating the data from the inertial sensors of the micro-electromechanical system (MEMS), and transmits wave parameters and spectra in real-time over cellular or satellite networks. LP was validated through: 1) sensor tests, 2) wave tank experiments, 3) a field validation against a Directional Waverider, 4) an inter-comparison of several buoys in the field, and 5) field measurements in the Baltic Sea marginal ice zone. These extensive field and laboratory tests confirmed that LP performed well (e.g., the bias of H_m0 in the field was 0.01 m, correlation 0.99 and scatter index of 8 %; the mean absolute deviation of mean wave direction was 7°). LP was also deployed with an Unmanned Aerial Vehicle and we present our experience of such operations. One issue that requires further development is the presence of low-frequency artefacts caused by the dynamic noise of the gyroscope. For now, a correction method is presented to deal with the noise.

The objective of this paper is to quantify resuspension and bed load transport of bottom sediments, induced by fast ferry wakes and wind waves near Aegna jetty, Tallinn Bay, using in situ measurements of waves, resuspension and optical properties of sea water. A new autonomous experimental set of two PAR-sensors, anchored into the sea bed, was used to measure the underwater irradiation. Wakes usually caused a rapid increase of the optical density of sea water by up to 50% from its background value. The total impact of fast ferry waves in terms of resuspended sediment concentration has not been substantially reduced compared to measurements in the past. However, wind waves apparently are the main driving force for both sediment resuspension and transport in 3 m deep water.

Sandy beaches high in recreation value make up 16% of the over 4000 km long shoreline of Estonia. The shore processes associated with climate change have remarkably accelerated over recent decades. Many sandy shores have suffered from strong erosion, including an excellent former beach at Valgeranna. The jetties, which were built in the 1860s to protect the navigation channel of Port Pärnu from clogging, have prevented natural sediment transport along the coast from south to north. At the same time, the sandy beach in Pärnu is expanding, and part of the sand accumulates with strong storms also in between the jetties, reducing the width of the shipping channel. The channel needs regular dredging, but, so far, the dredged sediment has been taken far away to the open sea and accumulated on the seabed. The current paper addresses the possibilities of using that sand for beach restoration in destructed and eroded areas. An overview of the applied methods and measurements during field studies is given. The results of modelling the processes of wave activity and sediment transport are discussed. The recycling of shore sediments is an important measure in sustainable coastal zone management. Different options and scenarios are analysed in order to find the most reasonable ways to bring sand back onto beaches and stabilize natural processes. Support from the state by working out respective laws and regulations would be motivating as well.

The use of renewable energy sources is one of the most promising options for slowing down climate change and the variability of resources would benefit the energy systems even further. Research provides an initial assessment of the Baltic Sea region concerning the possibility of using wave energy as a supplement to the current renewables in this region. During the study, the main parameters of the environment were examined (waves, salinity, tides, and the effect of ice). In addition to the technical and economic feasibility assessment (from a supplier perspective), marketability research was conducted among sector stakeholders through a survey. The majority of the respondents among maritime and energy sector stakeholders showed interest in applying wave energy in less than a 10-year perspective, particularly in the specific areas of their industries, such as seaports. This research is important as it demonstrates the limitations of the Baltic Sea environment, effects of regional economic activity, and local and EU level political, legal, and administrative burdens in applying wave energy within the studied region. Based on this study, policies and legislative frameworks need to be adapted (e.g., environmental protection areas and open access data of sea) to facilitate change.

This study assesses the wave energy potential and spectral variability in the Väinameri—a semi-sheltered, island-filtered basin on Estonia’s west coast—by combining six months of high-resolution in situ wave spectra with deep learning-enhanced satellite retrievals. Directional spectra were recorded at Rohuküla Harbor using a wave-following LainePoiss buoy from June to December 2024. In parallel, one-dimensional wave spectra were reconstructed from Sentinel-1 SAR imagery using a long short-term memory (LSTM) neural network trained on more than 71,000 collocations with NORA3 WAM hindcasts. Spectral pairs matched within a ±1 h window exhibited strong agreement in the dominant 0.2–0.4 Hz frequency band, while systematic underestimation at higher frequencies reflected both the radar resolution limits and the short-period, wind–sea-dominated nature of the Baltic Sea. Our results confirm that LSTM-enhanced SAR retrievals enable robust bulk and spectral wave characterizations in data-sparse nearshore regions, and offer a practical basis for the site evaluation, device tuning, and survivability testing of pilot-scale wave energy converters under both typical and storm-driven forcing conditions.

Dependence of near bottom currents and turbidity on wind and wave parameters is analyzed. Measurements campaigns with an acoustic Doppler velocymeter (ADV Field/Hydra, SonTek/YSI) were curried out in two bays in north western Estonia - the first one on Naissaar Shallow in Tallinn Bay (22.12.2009-12.01.2010, water depth 9 m, 37 cm from the bottom) and the second one in Keibu Bay (03.06.2010-26.06.2010, water depth 7m, 27 cm). Near bottom velocities were recorded with frequencies 2 Hz (currents) and 0.2 Hz (wave induced orbital motion). Additionally the water turbidity at the same level as flow measurements was performed using an integrated turbidity meter OBS 3+ (YSI). Wave parameters were recorded using a pressure wave gauge (PTR Group, Tallinn). The ADV measured flows consist of wind induced currents, wave induced orbital motions and turbulence. Maximum of wind induced currents reached meanly 10-15 cm/s at both measurement locations, while the maximum near bed orbital motions peaked over 40 cm/s. Measurements showed that the near bottom velocities in Keibu Bay were in correlation with wind speed, but turbidity values showed a significant increase only in some special weather conditions. From the comparison of ADV, turbidity meter and wave gauge characteristics it followed that turbidity was clearly depending on the wave energy. It means only quite long and high waves inducing bottom orbital velocities (calculated from the wave gauge data) over 20 cm/s were able to resuspend bottom sediments.